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ARM: Move generic arm instruction parsing code to new files for sharing between features 

Move the arm version of the kprobes instruction parsing code into more generic
files from where it can be used by uprobes and possibly other subsystems. The
symbol names will be made more generic in a subsequent part of this patchset.

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Jon Medhurst <tixy@linaro.org>
This commit is contained in:
David A. Long 2014-03-07 11:16:10 -05:00
parent b2531dd5e5
commit c18377c303
9 changed files with 1624 additions and 1513 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm/include/asm/probes.h
View File

@ -19,6 +19,8 @@
#ifndef _ASM_PROBES_H
#define _ASM_PROBES_H
struct kprobe;
typedef void (kprobe_insn_handler_t)(struct kprobe *, struct pt_regs *);
typedef unsigned long (kprobe_check_cc)(unsigned long);
typedef void (kprobe_insn_singlestep_t)(struct kprobe *, struct pt_regs *);

4
arch/arm/kernel/Makefile
View File

@ -50,11 +50,11 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o patch.o
obj-$(CONFIG_KPROBES) += probes.o kprobes.o kprobes-common.o patch.o
ifdef CONFIG_THUMB2_KERNEL
obj-$(CONFIG_KPROBES) += kprobes-thumb.o
else
obj-$(CONFIG_KPROBES) += kprobes-arm.o
obj-$(CONFIG_KPROBES) += kprobes-arm.o probes-arm.o
endif
obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o
test-kprobes-objs := kprobes-test.o

724
arch/arm/kernel/kprobes-arm.c
View File

@ -60,13 +60,10 @@
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include "kprobes.h"
#define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit)))))
#define branch_displacement(insn) sign_extend(((insn) & 0xffffff) << 2, 25)
#include "probes-arm.h"
#if __LINUX_ARM_ARCH__ >= 6
#define BLX(reg) "blx "reg" \n\t"
@ -75,88 +72,8 @@
"mov pc, "reg" \n\t"
#endif
/*
* To avoid the complications of mimicing single-stepping on a
* processor without a Next-PC or a single-step mode, and to
* avoid having to deal with the side-effects of boosting, we
* simulate or emulate (almost) all ARM instructions.
*
* "Simulation" is where the instruction's behavior is duplicated in
* C code. "Emulation" is where the original instruction is rewritten
* and executed, often by altering its registers.
*
* By having all behavior of the kprobe'd instruction completed before
* returning from the kprobe_handler(), all locks (scheduler and
* interrupt) can safely be released. There is no need for secondary
* breakpoints, no race with MP or preemptable kernels, nor having to
* clean up resources counts at a later time impacting overall system
* performance. By rewriting the instruction, only the minimum registers
* need to be loaded and saved back optimizing performance.
*
* Calling the insnslot_*_rwflags version of a function doesn't hurt
* anything even when the CPSR flags aren't updated by the
* instruction. It's just a little slower in return for saving
* a little space by not having a duplicate function that doesn't
* update the flags. (The same optimization can be said for
* instructions that do or don't perform register writeback)
* Also, instructions can either read the flags, only write the
* flags, or read and write the flags. To save combinations
* rather than for sheer performance, flag functions just assume
* read and write of flags.
*/
static void __kprobes simulate_bbl(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int disp = branch_displacement(insn);
if (insn & (1 << 24))
regs->ARM_lr = iaddr + 4;
regs->ARM_pc = iaddr + 8 + disp;
}
static void __kprobes simulate_blx1(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int disp = branch_displacement(insn);
regs->ARM_lr = iaddr + 4;
regs->ARM_pc = iaddr + 8 + disp + ((insn >> 23) & 0x2);
regs->ARM_cpsr |= PSR_T_BIT;
}
static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rm = insn & 0xf;
long rmv = regs->uregs[rm];
if (insn & (1 << 5))
regs->ARM_lr = (long)p->addr + 4;
regs->ARM_pc = rmv & ~0x1;
regs->ARM_cpsr &= ~PSR_T_BIT;
if (rmv & 0x1)
regs->ARM_cpsr |= PSR_T_BIT;
}
static void __kprobes simulate_mrs(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
unsigned long mask = 0xf8ff03df; /* Mask out execution state */
regs->uregs[rd] = regs->ARM_cpsr & mask;
}
static void __kprobes simulate_mov_ipsp(struct kprobe *p, struct pt_regs *regs)
{
regs->uregs[12] = regs->uregs[13];
}
static void __kprobes
void __kprobes
emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -185,7 +102,7 @@ emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rn] = rnv;
}
static void __kprobes
void __kprobes
emulate_ldr(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -215,7 +132,7 @@ emulate_ldr(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rn] = rnv;
}
static void __kprobes
void __kprobes
emulate_str(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -242,7 +159,7 @@ emulate_str(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rn] = rnv;
}
static void __kprobes
void __kprobes
emulate_rd12rn16rm0rs8_rwflags(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -277,7 +194,7 @@ emulate_rd12rn16rm0rs8_rwflags(struct kprobe *p, struct pt_regs *regs)
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}
static void __kprobes
void __kprobes
emulate_rd12rn16rm0_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -304,7 +221,7 @@ emulate_rd12rn16rm0_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}
static void __kprobes
void __kprobes
emulate_rd16rn12rm0rs8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -333,7 +250,7 @@ emulate_rd16rn12rm0rs8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}
static void __kprobes
void __kprobes
emulate_rd12rm0_noflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -353,7 +270,7 @@ emulate_rd12rm0_noflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rd] = rdv;
}
static void __kprobes
void __kprobes
emulate_rdlo12rdhi16rn0rm8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -382,624 +299,3 @@ emulate_rdlo12rdhi16rn0rm8_rwflags_nopc(struct kprobe *p, struct pt_regs *regs)
regs->uregs[rdhi] = rdhiv;
regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);
}
/*
* For the instruction masking and comparisons in all the "space_*"
* functions below, Do _not_ rearrange the order of tests unless
* you're very, very sure of what you are doing. For the sake of
* efficiency, the masks for some tests sometimes assume other test
* have been done prior to them so the number of patterns to test
* for an instruction set can be as broad as possible to reduce the
* number of tests needed.
*/
static const union decode_item arm_1111_table[] = {
/* Unconditional instructions */
/* memory hint 1111 0100 x001 xxxx xxxx xxxx xxxx xxxx */
/* PLDI (immediate) 1111 0100 x101 xxxx xxxx xxxx xxxx xxxx */
/* PLDW (immediate) 1111 0101 x001 xxxx xxxx xxxx xxxx xxxx */
/* PLD (immediate) 1111 0101 x101 xxxx xxxx xxxx xxxx xxxx */
DECODE_SIMULATE (0xfe300000, 0xf4100000, kprobe_simulate_nop),
/* memory hint 1111 0110 x001 xxxx xxxx xxxx xxx0 xxxx */
/* PLDI (register) 1111 0110 x101 xxxx xxxx xxxx xxx0 xxxx */
/* PLDW (register) 1111 0111 x001 xxxx xxxx xxxx xxx0 xxxx */
/* PLD (register) 1111 0111 x101 xxxx xxxx xxxx xxx0 xxxx */
DECODE_SIMULATE (0xfe300010, 0xf6100000, kprobe_simulate_nop),
/* BLX (immediate) 1111 101x xxxx xxxx xxxx xxxx xxxx xxxx */
DECODE_SIMULATE (0xfe000000, 0xfa000000, simulate_blx1),
/* CPS 1111 0001 0000 xxx0 xxxx xxxx xx0x xxxx */
/* SETEND 1111 0001 0000 0001 xxxx xxxx 0000 xxxx */
/* SRS 1111 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
/* RFE 1111 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* Coprocessor instructions... */
/* MCRR2 1111 1100 0100 xxxx xxxx xxxx xxxx xxxx */
/* MRRC2 1111 1100 0101 xxxx xxxx xxxx xxxx xxxx */
/* LDC2 1111 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
/* STC2 1111 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
/* CDP2 1111 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
/* MCR2 1111 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
/* MRC2 1111 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
/* Other unallocated instructions... */
DECODE_END
};
static const union decode_item arm_cccc_0001_0xx0____0xxx_table[] = {
/* Miscellaneous instructions */
/* MRS cpsr cccc 0001 0000 xxxx xxxx xxxx 0000 xxxx */
DECODE_SIMULATEX(0x0ff000f0, 0x01000000, simulate_mrs,
REGS(0, NOPC, 0, 0, 0)),
/* BX cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
DECODE_SIMULATE (0x0ff000f0, 0x01200010, simulate_blx2bx),
/* BLX (register) cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
DECODE_SIMULATEX(0x0ff000f0, 0x01200030, simulate_blx2bx,
REGS(0, 0, 0, 0, NOPC)),
/* CLZ cccc 0001 0110 xxxx xxxx xxxx 0001 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x01600010, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* QADD cccc 0001 0000 xxxx xxxx xxxx 0101 xxxx */
/* QSUB cccc 0001 0010 xxxx xxxx xxxx 0101 xxxx */
/* QDADD cccc 0001 0100 xxxx xxxx xxxx 0101 xxxx */
/* QDSUB cccc 0001 0110 xxxx xxxx xxxx 0101 xxxx */
DECODE_EMULATEX (0x0f9000f0, 0x01000050, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* BXJ cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
/* MSR cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
/* MRS spsr cccc 0001 0100 xxxx xxxx xxxx 0000 xxxx */
/* BKPT 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
/* SMC cccc 0001 0110 xxxx xxxx xxxx 0111 xxxx */
/* And unallocated instructions... */
DECODE_END
};
static const union decode_item arm_cccc_0001_0xx0____1xx0_table[] = {
/* Halfword multiply and multiply-accumulate */
/* SMLALxy cccc 0001 0100 xxxx xxxx xxxx 1xx0 xxxx */
DECODE_EMULATEX (0x0ff00090, 0x01400080, emulate_rdlo12rdhi16rn0rm8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* SMULWy cccc 0001 0010 xxxx xxxx xxxx 1x10 xxxx */
DECODE_OR (0x0ff000b0, 0x012000a0),
/* SMULxy cccc 0001 0110 xxxx xxxx xxxx 1xx0 xxxx */
DECODE_EMULATEX (0x0ff00090, 0x01600080, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, 0, NOPC, 0, NOPC)),
/* SMLAxy cccc 0001 0000 xxxx xxxx xxxx 1xx0 xxxx */
DECODE_OR (0x0ff00090, 0x01000080),
/* SMLAWy cccc 0001 0010 xxxx xxxx xxxx 1x00 xxxx */
DECODE_EMULATEX (0x0ff000b0, 0x01200080, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_0000_____1001_table[] = {
/* Multiply and multiply-accumulate */
/* MUL cccc 0000 0000 xxxx xxxx xxxx 1001 xxxx */
/* MULS cccc 0000 0001 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0fe000f0, 0x00000090, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, 0, NOPC, 0, NOPC)),
/* MLA cccc 0000 0010 xxxx xxxx xxxx 1001 xxxx */
/* MLAS cccc 0000 0011 xxxx xxxx xxxx 1001 xxxx */
DECODE_OR (0x0fe000f0, 0x00200090),
/* MLS cccc 0000 0110 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x00600090, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* UMAAL cccc 0000 0100 xxxx xxxx xxxx 1001 xxxx */
DECODE_OR (0x0ff000f0, 0x00400090),
/* UMULL cccc 0000 1000 xxxx xxxx xxxx 1001 xxxx */
/* UMULLS cccc 0000 1001 xxxx xxxx xxxx 1001 xxxx */
/* UMLAL cccc 0000 1010 xxxx xxxx xxxx 1001 xxxx */
/* UMLALS cccc 0000 1011 xxxx xxxx xxxx 1001 xxxx */
/* SMULL cccc 0000 1100 xxxx xxxx xxxx 1001 xxxx */
/* SMULLS cccc 0000 1101 xxxx xxxx xxxx 1001 xxxx */
/* SMLAL cccc 0000 1110 xxxx xxxx xxxx 1001 xxxx */
/* SMLALS cccc 0000 1111 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0f8000f0, 0x00800090, emulate_rdlo12rdhi16rn0rm8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_0001_____1001_table[] = {
/* Synchronization primitives */
#if __LINUX_ARM_ARCH__ < 6
/* Deprecated on ARMv6 and may be UNDEFINED on v7 */
/* SMP/SWPB cccc 0001 0x00 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0fb000f0, 0x01000090, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
#endif
/* LDREX/STREX{,D,B,H} cccc 0001 1xxx xxxx xxxx xxxx 1001 xxxx */
/* And unallocated instructions... */
DECODE_END
};
static const union decode_item arm_cccc_000x_____1xx1_table[] = {
/* Extra load/store instructions */
/* STRHT cccc 0000 xx10 xxxx xxxx xxxx 1011 xxxx */
/* ??? cccc 0000 xx10 xxxx xxxx xxxx 11x1 xxxx */
/* LDRHT cccc 0000 xx11 xxxx xxxx xxxx 1011 xxxx */
/* LDRSBT cccc 0000 xx11 xxxx xxxx xxxx 1101 xxxx */
/* LDRSHT cccc 0000 xx11 xxxx xxxx xxxx 1111 xxxx */
DECODE_REJECT (0x0f200090, 0x00200090),
/* LDRD/STRD lr,pc,{... cccc 000x x0x0 xxxx 111x xxxx 1101 xxxx */
DECODE_REJECT (0x0e10e0d0, 0x0000e0d0),
/* LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx */
/* STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e5000d0, 0x000000d0, emulate_ldrdstrd,
REGS(NOPCWB, NOPCX, 0, 0, NOPC)),
/* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx */
/* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e5000d0, 0x004000d0, emulate_ldrdstrd,
REGS(NOPCWB, NOPCX, 0, 0, 0)),
/* STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0e5000f0, 0x000000b0, emulate_str,
REGS(NOPCWB, NOPC, 0, 0, NOPC)),
/* LDRH (register) cccc 000x x0x1 xxxx xxxx xxxx 1011 xxxx */
/* LDRSB (register) cccc 000x x0x1 xxxx xxxx xxxx 1101 xxxx */
/* LDRSH (register) cccc 000x x0x1 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e500090, 0x00100090, emulate_ldr,
REGS(NOPCWB, NOPC, 0, 0, NOPC)),
/* STRH (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0e5000f0, 0x004000b0, emulate_str,
REGS(NOPCWB, NOPC, 0, 0, 0)),
/* LDRH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1011 xxxx */
/* LDRSB (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1101 xxxx */
/* LDRSH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e500090, 0x00500090, emulate_ldr,
REGS(NOPCWB, NOPC, 0, 0, 0)),
DECODE_END
};
static const union decode_item arm_cccc_000x_table[] = {
/* Data-processing (register) */
/* <op>S PC, ... cccc 000x xxx1 xxxx 1111 xxxx xxxx xxxx */
DECODE_REJECT (0x0e10f000, 0x0010f000),
/* MOV IP, SP 1110 0001 1010 0000 1100 0000 0000 1101 */
DECODE_SIMULATE (0xffffffff, 0xe1a0c00d, simulate_mov_ipsp),
/* TST (register) cccc 0001 0001 xxxx xxxx xxxx xxx0 xxxx */
/* TEQ (register) cccc 0001 0011 xxxx xxxx xxxx xxx0 xxxx */
/* CMP (register) cccc 0001 0101 xxxx xxxx xxxx xxx0 xxxx */
/* CMN (register) cccc 0001 0111 xxxx xxxx xxxx xxx0 xxxx */
DECODE_EMULATEX (0x0f900010, 0x01100000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, 0, 0, 0, ANY)),
/* MOV (register) cccc 0001 101x xxxx xxxx xxxx xxx0 xxxx */
/* MVN (register) cccc 0001 111x xxxx xxxx xxxx xxx0 xxxx */
DECODE_EMULATEX (0x0fa00010, 0x01a00000, emulate_rd12rn16rm0rs8_rwflags,
REGS(0, ANY, 0, 0, ANY)),
/* AND (register) cccc 0000 000x xxxx xxxx xxxx xxx0 xxxx */
/* EOR (register) cccc 0000 001x xxxx xxxx xxxx xxx0 xxxx */
/* SUB (register) cccc 0000 010x xxxx xxxx xxxx xxx0 xxxx */
/* RSB (register) cccc 0000 011x xxxx xxxx xxxx xxx0 xxxx */
/* ADD (register) cccc 0000 100x xxxx xxxx xxxx xxx0 xxxx */
/* ADC (register) cccc 0000 101x xxxx xxxx xxxx xxx0 xxxx */
/* SBC (register) cccc 0000 110x xxxx xxxx xxxx xxx0 xxxx */
/* RSC (register) cccc 0000 111x xxxx xxxx xxxx xxx0 xxxx */
/* ORR (register) cccc 0001 100x xxxx xxxx xxxx xxx0 xxxx */
/* BIC (register) cccc 0001 110x xxxx xxxx xxxx xxx0 xxxx */
DECODE_EMULATEX (0x0e000010, 0x00000000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, ANY, 0, 0, ANY)),
/* TST (reg-shift reg) cccc 0001 0001 xxxx xxxx xxxx 0xx1 xxxx */
/* TEQ (reg-shift reg) cccc 0001 0011 xxxx xxxx xxxx 0xx1 xxxx */
/* CMP (reg-shift reg) cccc 0001 0101 xxxx xxxx xxxx 0xx1 xxxx */
/* CMN (reg-shift reg) cccc 0001 0111 xxxx xxxx xxxx 0xx1 xxxx */
DECODE_EMULATEX (0x0f900090, 0x01100010, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, 0, NOPC, 0, ANY)),
/* MOV (reg-shift reg) cccc 0001 101x xxxx xxxx xxxx 0xx1 xxxx */
/* MVN (reg-shift reg) cccc 0001 111x xxxx xxxx xxxx 0xx1 xxxx */
DECODE_EMULATEX (0x0fa00090, 0x01a00010, emulate_rd12rn16rm0rs8_rwflags,
REGS(0, ANY, NOPC, 0, ANY)),
/* AND (reg-shift reg) cccc 0000 000x xxxx xxxx xxxx 0xx1 xxxx */
/* EOR (reg-shift reg) cccc 0000 001x xxxx xxxx xxxx 0xx1 xxxx */
/* SUB (reg-shift reg) cccc 0000 010x xxxx xxxx xxxx 0xx1 xxxx */
/* RSB (reg-shift reg) cccc 0000 011x xxxx xxxx xxxx 0xx1 xxxx */
/* ADD (reg-shift reg) cccc 0000 100x xxxx xxxx xxxx 0xx1 xxxx */
/* ADC (reg-shift reg) cccc 0000 101x xxxx xxxx xxxx 0xx1 xxxx */
/* SBC (reg-shift reg) cccc 0000 110x xxxx xxxx xxxx 0xx1 xxxx */
/* RSC (reg-shift reg) cccc 0000 111x xxxx xxxx xxxx 0xx1 xxxx */
/* ORR (reg-shift reg) cccc 0001 100x xxxx xxxx xxxx 0xx1 xxxx */
/* BIC (reg-shift reg) cccc 0001 110x xxxx xxxx xxxx 0xx1 xxxx */
DECODE_EMULATEX (0x0e000090, 0x00000010, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, ANY, NOPC, 0, ANY)),
DECODE_END
};
static const union decode_item arm_cccc_001x_table[] = {
/* Data-processing (immediate) */
/* MOVW cccc 0011 0000 xxxx xxxx xxxx xxxx xxxx */
/* MOVT cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0fb00000, 0x03000000, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, 0)),
/* YIELD cccc 0011 0010 0000 xxxx xxxx 0000 0001 */
DECODE_OR (0x0fff00ff, 0x03200001),
/* SEV cccc 0011 0010 0000 xxxx xxxx 0000 0100 */
DECODE_EMULATE (0x0fff00ff, 0x03200004, kprobe_emulate_none),
/* NOP cccc 0011 0010 0000 xxxx xxxx 0000 0000 */
/* WFE cccc 0011 0010 0000 xxxx xxxx 0000 0010 */
/* WFI cccc 0011 0010 0000 xxxx xxxx 0000 0011 */
DECODE_SIMULATE (0x0fff00fc, 0x03200000, kprobe_simulate_nop),
/* DBG cccc 0011 0010 0000 xxxx xxxx ffff xxxx */
/* unallocated hints cccc 0011 0010 0000 xxxx xxxx xxxx xxxx */
/* MSR (immediate) cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0fb00000, 0x03200000),
/* <op>S PC, ... cccc 001x xxx1 xxxx 1111 xxxx xxxx xxxx */
DECODE_REJECT (0x0e10f000, 0x0210f000),
/* TST (immediate) cccc 0011 0001 xxxx xxxx xxxx xxxx xxxx */
/* TEQ (immediate) cccc 0011 0011 xxxx xxxx xxxx xxxx xxxx */
/* CMP (immediate) cccc 0011 0101 xxxx xxxx xxxx xxxx xxxx */
/* CMN (immediate) cccc 0011 0111 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0f900000, 0x03100000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, 0, 0, 0, 0)),
/* MOV (immediate) cccc 0011 101x xxxx xxxx xxxx xxxx xxxx */
/* MVN (immediate) cccc 0011 111x xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0fa00000, 0x03a00000, emulate_rd12rn16rm0rs8_rwflags,
REGS(0, ANY, 0, 0, 0)),
/* AND (immediate) cccc 0010 000x xxxx xxxx xxxx xxxx xxxx */
/* EOR (immediate) cccc 0010 001x xxxx xxxx xxxx xxxx xxxx */
/* SUB (immediate) cccc 0010 010x xxxx xxxx xxxx xxxx xxxx */
/* RSB (immediate) cccc 0010 011x xxxx xxxx xxxx xxxx xxxx */
/* ADD (immediate) cccc 0010 100x xxxx xxxx xxxx xxxx xxxx */
/* ADC (immediate) cccc 0010 101x xxxx xxxx xxxx xxxx xxxx */
/* SBC (immediate) cccc 0010 110x xxxx xxxx xxxx xxxx xxxx */
/* RSC (immediate) cccc 0010 111x xxxx xxxx xxxx xxxx xxxx */
/* ORR (immediate) cccc 0011 100x xxxx xxxx xxxx xxxx xxxx */
/* BIC (immediate) cccc 0011 110x xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e000000, 0x02000000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, ANY, 0, 0, 0)),
DECODE_END
};
static const union decode_item arm_cccc_0110_____xxx1_table[] = {
/* Media instructions */
/* SEL cccc 0110 1000 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x068000b0, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* SSAT cccc 0110 101x xxxx xxxx xxxx xx01 xxxx */
/* USAT cccc 0110 111x xxxx xxxx xxxx xx01 xxxx */
DECODE_OR(0x0fa00030, 0x06a00010),
/* SSAT16 cccc 0110 1010 xxxx xxxx xxxx 0011 xxxx */
/* USAT16 cccc 0110 1110 xxxx xxxx xxxx 0011 xxxx */
DECODE_EMULATEX (0x0fb000f0, 0x06a00030, emulate_rd12rn16rm0_rwflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* REV cccc 0110 1011 xxxx xxxx xxxx 0011 xxxx */
/* REV16 cccc 0110 1011 xxxx xxxx xxxx 1011 xxxx */
/* RBIT cccc 0110 1111 xxxx xxxx xxxx 0011 xxxx */
/* REVSH cccc 0110 1111 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0fb00070, 0x06b00030, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* ??? cccc 0110 0x00 xxxx xxxx xxxx xxx1 xxxx */
DECODE_REJECT (0x0fb00010, 0x06000010),
/* ??? cccc 0110 0xxx xxxx xxxx xxxx 1011 xxxx */
DECODE_REJECT (0x0f8000f0, 0x060000b0),
/* ??? cccc 0110 0xxx xxxx xxxx xxxx 1101 xxxx */
DECODE_REJECT (0x0f8000f0, 0x060000d0),
/* SADD16 cccc 0110 0001 xxxx xxxx xxxx 0001 xxxx */
/* SADDSUBX cccc 0110 0001 xxxx xxxx xxxx 0011 xxxx */
/* SSUBADDX cccc 0110 0001 xxxx xxxx xxxx 0101 xxxx */
/* SSUB16 cccc 0110 0001 xxxx xxxx xxxx 0111 xxxx */
/* SADD8 cccc 0110 0001 xxxx xxxx xxxx 1001 xxxx */
/* SSUB8 cccc 0110 0001 xxxx xxxx xxxx 1111 xxxx */
/* QADD16 cccc 0110 0010 xxxx xxxx xxxx 0001 xxxx */
/* QADDSUBX cccc 0110 0010 xxxx xxxx xxxx 0011 xxxx */
/* QSUBADDX cccc 0110 0010 xxxx xxxx xxxx 0101 xxxx */
/* QSUB16 cccc 0110 0010 xxxx xxxx xxxx 0111 xxxx */
/* QADD8 cccc 0110 0010 xxxx xxxx xxxx 1001 xxxx */
/* QSUB8 cccc 0110 0010 xxxx xxxx xxxx 1111 xxxx */
/* SHADD16 cccc 0110 0011 xxxx xxxx xxxx 0001 xxxx */
/* SHADDSUBX cccc 0110 0011 xxxx xxxx xxxx 0011 xxxx */
/* SHSUBADDX cccc 0110 0011 xxxx xxxx xxxx 0101 xxxx */
/* SHSUB16 cccc 0110 0011 xxxx xxxx xxxx 0111 xxxx */
/* SHADD8 cccc 0110 0011 xxxx xxxx xxxx 1001 xxxx */
/* SHSUB8 cccc 0110 0011 xxxx xxxx xxxx 1111 xxxx */
/* UADD16 cccc 0110 0101 xxxx xxxx xxxx 0001 xxxx */
/* UADDSUBX cccc 0110 0101 xxxx xxxx xxxx 0011 xxxx */
/* USUBADDX cccc 0110 0101 xxxx xxxx xxxx 0101 xxxx */
/* USUB16 cccc 0110 0101 xxxx xxxx xxxx 0111 xxxx */
/* UADD8 cccc 0110 0101 xxxx xxxx xxxx 1001 xxxx */
/* USUB8 cccc 0110 0101 xxxx xxxx xxxx 1111 xxxx */
/* UQADD16 cccc 0110 0110 xxxx xxxx xxxx 0001 xxxx */
/* UQADDSUBX cccc 0110 0110 xxxx xxxx xxxx 0011 xxxx */
/* UQSUBADDX cccc 0110 0110 xxxx xxxx xxxx 0101 xxxx */
/* UQSUB16 cccc 0110 0110 xxxx xxxx xxxx 0111 xxxx */
/* UQADD8 cccc 0110 0110 xxxx xxxx xxxx 1001 xxxx */
/* UQSUB8 cccc 0110 0110 xxxx xxxx xxxx 1111 xxxx */
/* UHADD16 cccc 0110 0111 xxxx xxxx xxxx 0001 xxxx */
/* UHADDSUBX cccc 0110 0111 xxxx xxxx xxxx 0011 xxxx */
/* UHSUBADDX cccc 0110 0111 xxxx xxxx xxxx 0101 xxxx */
/* UHSUB16 cccc 0110 0111 xxxx xxxx xxxx 0111 xxxx */
/* UHADD8 cccc 0110 0111 xxxx xxxx xxxx 1001 xxxx */
/* UHSUB8 cccc 0110 0111 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0f800010, 0x06000010, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* PKHBT cccc 0110 1000 xxxx xxxx xxxx x001 xxxx */
/* PKHTB cccc 0110 1000 xxxx xxxx xxxx x101 xxxx */
DECODE_EMULATEX (0x0ff00030, 0x06800010, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* ??? cccc 0110 1001 xxxx xxxx xxxx 0111 xxxx */
/* ??? cccc 0110 1101 xxxx xxxx xxxx 0111 xxxx */
DECODE_REJECT (0x0fb000f0, 0x06900070),
/* SXTB16 cccc 0110 1000 1111 xxxx xxxx 0111 xxxx */
/* SXTB cccc 0110 1010 1111 xxxx xxxx 0111 xxxx */
/* SXTH cccc 0110 1011 1111 xxxx xxxx 0111 xxxx */
/* UXTB16 cccc 0110 1100 1111 xxxx xxxx 0111 xxxx */
/* UXTB cccc 0110 1110 1111 xxxx xxxx 0111 xxxx */
/* UXTH cccc 0110 1111 1111 xxxx xxxx 0111 xxxx */
DECODE_EMULATEX (0x0f8f00f0, 0x068f0070, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* SXTAB16 cccc 0110 1000 xxxx xxxx xxxx 0111 xxxx */
/* SXTAB cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx */
/* SXTAH cccc 0110 1011 xxxx xxxx xxxx 0111 xxxx */
/* UXTAB16 cccc 0110 1100 xxxx xxxx xxxx 0111 xxxx */
/* UXTAB cccc 0110 1110 xxxx xxxx xxxx 0111 xxxx */
/* UXTAH cccc 0110 1111 xxxx xxxx xxxx 0111 xxxx */
DECODE_EMULATEX (0x0f8000f0, 0x06800070, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPCX, NOPC, 0, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_0111_____xxx1_table[] = {
/* Media instructions */
/* UNDEFINED cccc 0111 1111 xxxx xxxx xxxx 1111 xxxx */
DECODE_REJECT (0x0ff000f0, 0x07f000f0),
/* SMLALD cccc 0111 0100 xxxx xxxx xxxx 00x1 xxxx */
/* SMLSLD cccc 0111 0100 xxxx xxxx xxxx 01x1 xxxx */
DECODE_EMULATEX (0x0ff00090, 0x07400010, emulate_rdlo12rdhi16rn0rm8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* SMUAD cccc 0111 0000 xxxx 1111 xxxx 00x1 xxxx */
/* SMUSD cccc 0111 0000 xxxx 1111 xxxx 01x1 xxxx */
DECODE_OR (0x0ff0f090, 0x0700f010),
/* SMMUL cccc 0111 0101 xxxx 1111 xxxx 00x1 xxxx */
DECODE_OR (0x0ff0f0d0, 0x0750f010),
/* USAD8 cccc 0111 1000 xxxx 1111 xxxx 0001 xxxx */
DECODE_EMULATEX (0x0ff0f0f0, 0x0780f010, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, 0, NOPC, 0, NOPC)),
/* SMLAD cccc 0111 0000 xxxx xxxx xxxx 00x1 xxxx */
/* SMLSD cccc 0111 0000 xxxx xxxx xxxx 01x1 xxxx */
DECODE_OR (0x0ff00090, 0x07000010),
/* SMMLA cccc 0111 0101 xxxx xxxx xxxx 00x1 xxxx */
DECODE_OR (0x0ff000d0, 0x07500010),
/* USADA8 cccc 0111 1000 xxxx xxxx xxxx 0001 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x07800010, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPCX, NOPC, 0, NOPC)),
/* SMMLS cccc 0111 0101 xxxx xxxx xxxx 11x1 xxxx */
DECODE_EMULATEX (0x0ff000d0, 0x075000d0, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* SBFX cccc 0111 101x xxxx xxxx xxxx x101 xxxx */
/* UBFX cccc 0111 111x xxxx xxxx xxxx x101 xxxx */
DECODE_EMULATEX (0x0fa00070, 0x07a00050, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* BFC cccc 0111 110x xxxx xxxx xxxx x001 1111 */
DECODE_EMULATEX (0x0fe0007f, 0x07c0001f, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, 0)),
/* BFI cccc 0111 110x xxxx xxxx xxxx x001 xxxx */
DECODE_EMULATEX (0x0fe00070, 0x07c00010, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPCX)),
DECODE_END
};
static const union decode_item arm_cccc_01xx_table[] = {
/* Load/store word and unsigned byte */
/* LDRB/STRB pc,[...] cccc 01xx x0xx xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0c40f000, 0x0440f000),
/* STRT cccc 01x0 x010 xxxx xxxx xxxx xxxx xxxx */
/* LDRT cccc 01x0 x011 xxxx xxxx xxxx xxxx xxxx */
/* STRBT cccc 01x0 x110 xxxx xxxx xxxx xxxx xxxx */
/* LDRBT cccc 01x0 x111 xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0d200000, 0x04200000),
/* STR (immediate) cccc 010x x0x0 xxxx xxxx xxxx xxxx xxxx */
/* STRB (immediate) cccc 010x x1x0 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x04000000, emulate_str,
REGS(NOPCWB, ANY, 0, 0, 0)),
/* LDR (immediate) cccc 010x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* LDRB (immediate) cccc 010x x1x1 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x04100000, emulate_ldr,
REGS(NOPCWB, ANY, 0, 0, 0)),
/* STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx */
/* STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x06000000, emulate_str,
REGS(NOPCWB, ANY, 0, 0, NOPC)),
/* LDR (register) cccc 011x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* LDRB (register) cccc 011x x1x1 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x06100000, emulate_ldr,
REGS(NOPCWB, ANY, 0, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_100x_table[] = {
/* Block data transfer instructions */
/* LDM cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* STM cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */
DECODE_CUSTOM (0x0e400000, 0x08000000, kprobe_decode_ldmstm),
/* STM (user registers) cccc 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
/* LDM (user registers) cccc 100x x1x1 xxxx 0xxx xxxx xxxx xxxx */
/* LDM (exception ret) cccc 100x x1x1 xxxx 1xxx xxxx xxxx xxxx */
DECODE_END
};
const union decode_item kprobe_decode_arm_table[] = {
/*
* Unconditional instructions
* 1111 xxxx xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0xf0000000, 0xf0000000, arm_1111_table),
/*
* Miscellaneous instructions
* cccc 0001 0xx0 xxxx xxxx xxxx 0xxx xxxx
*/
DECODE_TABLE (0x0f900080, 0x01000000, arm_cccc_0001_0xx0____0xxx_table),
/*
* Halfword multiply and multiply-accumulate
* cccc 0001 0xx0 xxxx xxxx xxxx 1xx0 xxxx
*/
DECODE_TABLE (0x0f900090, 0x01000080, arm_cccc_0001_0xx0____1xx0_table),
/*
* Multiply and multiply-accumulate
* cccc 0000 xxxx xxxx xxxx xxxx 1001 xxxx
*/
DECODE_TABLE (0x0f0000f0, 0x00000090, arm_cccc_0000_____1001_table),
/*
* Synchronization primitives
* cccc 0001 xxxx xxxx xxxx xxxx 1001 xxxx
*/
DECODE_TABLE (0x0f0000f0, 0x01000090, arm_cccc_0001_____1001_table),
/*
* Extra load/store instructions
* cccc 000x xxxx xxxx xxxx xxxx 1xx1 xxxx
*/
DECODE_TABLE (0x0e000090, 0x00000090, arm_cccc_000x_____1xx1_table),
/*
* Data-processing (register)
* cccc 000x xxxx xxxx xxxx xxxx xxx0 xxxx
* Data-processing (register-shifted register)
* cccc 000x xxxx xxxx xxxx xxxx 0xx1 xxxx
*/
DECODE_TABLE (0x0e000000, 0x00000000, arm_cccc_000x_table),
/*
* Data-processing (immediate)
* cccc 001x xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0x0e000000, 0x02000000, arm_cccc_001x_table),
/*
* Media instructions
* cccc 011x xxxx xxxx xxxx xxxx xxx1 xxxx
*/
DECODE_TABLE (0x0f000010, 0x06000010, arm_cccc_0110_____xxx1_table),
DECODE_TABLE (0x0f000010, 0x07000010, arm_cccc_0111_____xxx1_table),
/*
* Load/store word and unsigned byte
* cccc 01xx xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0x0c000000, 0x04000000, arm_cccc_01xx_table),
/*
* Block data transfer instructions
* cccc 100x xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0x0e000000, 0x08000000, arm_cccc_100x_table),
/* B cccc 1010 xxxx xxxx xxxx xxxx xxxx xxxx */
/* BL cccc 1011 xxxx xxxx xxxx xxxx xxxx xxxx */
DECODE_SIMULATE (0x0e000000, 0x0a000000, simulate_bbl),
/*
* Supervisor Call, and coprocessor instructions
*/
/* MCRR cccc 1100 0100 xxxx xxxx xxxx xxxx xxxx */
/* MRRC cccc 1100 0101 xxxx xxxx xxxx xxxx xxxx */
/* LDC cccc 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
/* STC cccc 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
/* CDP cccc 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
/* MCR cccc 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
/* MRC cccc 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
/* SVC cccc 1111 xxxx xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0c000000, 0x0c000000),
DECODE_END
};
#ifdef CONFIG_ARM_KPROBES_TEST_MODULE
EXPORT_SYMBOL_GPL(kprobe_decode_arm_table);
#endif
static void __kprobes arm_singlestep(struct kprobe *p, struct pt_regs *regs)
{
regs->ARM_pc += 4;
p->ainsn.insn_handler(p, regs);
}
/* Return:
* INSN_REJECTED If instruction is one not allowed to kprobe,
* INSN_GOOD If instruction is supported and uses instruction slot,
* INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
*
* For instructions we don't want to kprobe (INSN_REJECTED return result):
* These are generally ones that modify the processor state making
* them "hard" to simulate such as switches processor modes or
* make accesses in alternate modes. Any of these could be simulated
* if the work was put into it, but low return considering they
* should also be very rare.
*/
enum kprobe_insn __kprobes
arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
asi->insn_singlestep = arm_singlestep;
asi->insn_check_cc = kprobe_condition_checks[insn>>28];
return kprobe_decode_insn(insn, asi, kprobe_decode_arm_table, false);
}

425
arch/arm/kernel/kprobes-common.c
View File

@ -13,178 +13,10 @@
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <asm/system_info.h>
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/bug.h>
#include "kprobes.h"
#ifndef find_str_pc_offset
/*
* For STR and STM instructions, an ARM core may choose to use either
* a +8 or a +12 displacement from the current instruction's address.
* Whichever value is chosen for a given core, it must be the same for
* both instructions and may not change. This function measures it.
*/
int str_pc_offset;
void __init find_str_pc_offset(void)
{
int addr, scratch, ret;
__asm__ (
"sub %[ret], pc, #4 \n\t"
"str pc, %[addr] \n\t"
"ldr %[scr], %[addr] \n\t"
"sub %[ret], %[scr], %[ret] \n\t"
: [ret] "=r" (ret), [scr] "=r" (scratch), [addr] "+m" (addr));
str_pc_offset = ret;
}
#endif /* !find_str_pc_offset */
#ifndef test_load_write_pc_interworking
bool load_write_pc_interworks;
void __init test_load_write_pc_interworking(void)
{
int arch = cpu_architecture();
BUG_ON(arch == CPU_ARCH_UNKNOWN);
load_write_pc_interworks = arch >= CPU_ARCH_ARMv5T;
}
#endif /* !test_load_write_pc_interworking */
#ifndef test_alu_write_pc_interworking
bool alu_write_pc_interworks;
void __init test_alu_write_pc_interworking(void)
{
int arch = cpu_architecture();
BUG_ON(arch == CPU_ARCH_UNKNOWN);
alu_write_pc_interworks = arch >= CPU_ARCH_ARMv7;
}
#endif /* !test_alu_write_pc_interworking */
void __init arm_kprobe_decode_init(void)
{
find_str_pc_offset();
test_load_write_pc_interworking();
test_alu_write_pc_interworking();
}
static unsigned long __kprobes __check_eq(unsigned long cpsr)
{
return cpsr & PSR_Z_BIT;
}
static unsigned long __kprobes __check_ne(unsigned long cpsr)
{
return (~cpsr) & PSR_Z_BIT;
}
static unsigned long __kprobes __check_cs(unsigned long cpsr)
{
return cpsr & PSR_C_BIT;
}
static unsigned long __kprobes __check_cc(unsigned long cpsr)
{
return (~cpsr) & PSR_C_BIT;
}
static unsigned long __kprobes __check_mi(unsigned long cpsr)
{
return cpsr & PSR_N_BIT;
}
static unsigned long __kprobes __check_pl(unsigned long cpsr)
{
return (~cpsr) & PSR_N_BIT;
}
static unsigned long __kprobes __check_vs(unsigned long cpsr)
{
return cpsr & PSR_V_BIT;
}
static unsigned long __kprobes __check_vc(unsigned long cpsr)
{
return (~cpsr) & PSR_V_BIT;
}
static unsigned long __kprobes __check_hi(unsigned long cpsr)
{
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return cpsr & PSR_C_BIT;
}
static unsigned long __kprobes __check_ls(unsigned long cpsr)
{
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return (~cpsr) & PSR_C_BIT;
}
static unsigned long __kprobes __check_ge(unsigned long cpsr)
{
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return (~cpsr) & PSR_N_BIT;
}
static unsigned long __kprobes __check_lt(unsigned long cpsr)
{
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return cpsr & PSR_N_BIT;
}
static unsigned long __kprobes __check_gt(unsigned long cpsr)
{
unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return (~temp) & PSR_N_BIT;
}
static unsigned long __kprobes __check_le(unsigned long cpsr)
{
unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return temp & PSR_N_BIT;
}
static unsigned long __kprobes __check_al(unsigned long cpsr)
{
return true;
}
kprobe_check_cc * const kprobe_condition_checks[16] = {
&__check_eq, &__check_ne, &__check_cs, &__check_cc,
&__check_mi, &__check_pl, &__check_vs, &__check_vc,
&__check_hi, &__check_ls, &__check_ge, &__check_lt,
&__check_gt, &__check_le, &__check_al, &__check_al
};
void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs)
{
}
void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs)
{
p->ainsn.insn_fn();
}
static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
@ -322,260 +154,3 @@ kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)
return INSN_GOOD_NO_SLOT;
}
/*
* Prepare an instruction slot to receive an instruction for emulating.
* This is done by placing a subroutine return after the location where the
* instruction will be placed. We also modify ARM instructions to be
* unconditional as the condition code will already be checked before any
* emulation handler is called.
*/
static kprobe_opcode_t __kprobes
prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
bool thumb)
{
#ifdef CONFIG_THUMB2_KERNEL
if (thumb) {
u16 *thumb_insn = (u16 *)asi->insn;
thumb_insn[1] = 0x4770; /* Thumb bx lr */
thumb_insn[2] = 0x4770; /* Thumb bx lr */
return insn;
}
asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
#else
asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
#endif
/* Make an ARM instruction unconditional */
if (insn < 0xe0000000)
insn = (insn | 0xe0000000) & ~0x10000000;
return insn;
}
/*
* Write a (probably modified) instruction into the slot previously prepared by
* prepare_emulated_insn
*/
static void __kprobes
set_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
bool thumb)
{
#ifdef CONFIG_THUMB2_KERNEL
if (thumb) {
u16 *ip = (u16 *)asi->insn;
if (is_wide_instruction(insn))
*ip++ = insn >> 16;
*ip++ = insn;
return;
}
#endif
asi->insn[0] = insn;
}
/*
* When we modify the register numbers encoded in an instruction to be emulated,
* the new values come from this define. For ARM and 32-bit Thumb instructions
* this gives...
*
* bit position 16 12 8 4 0
* ---------------+---+---+---+---+---+
* register r2 r0 r1 -- r3
*/
#define INSN_NEW_BITS 0x00020103
/* Each nibble has same value as that at INSN_NEW_BITS bit 16 */
#define INSN_SAMEAS16_BITS 0x22222222
/*
* Validate and modify each of the registers encoded in an instruction.
*
* Each nibble in regs contains a value from enum decode_reg_type. For each
* non-zero value, the corresponding nibble in pinsn is validated and modified
* according to the type.
*/
static bool __kprobes decode_regs(kprobe_opcode_t* pinsn, u32 regs)
{
kprobe_opcode_t insn = *pinsn;
kprobe_opcode_t mask = 0xf; /* Start at least significant nibble */
for (; regs != 0; regs >>= 4, mask <<= 4) {
kprobe_opcode_t new_bits = INSN_NEW_BITS;
switch (regs & 0xf) {
case REG_TYPE_NONE:
/* Nibble not a register, skip to next */
continue;
case REG_TYPE_ANY:
/* Any register is allowed */
break;
case REG_TYPE_SAMEAS16:
/* Replace register with same as at bit position 16 */
new_bits = INSN_SAMEAS16_BITS;
break;
case REG_TYPE_SP:
/* Only allow SP (R13) */
if ((insn ^ 0xdddddddd) & mask)
goto reject;
break;
case REG_TYPE_PC:
/* Only allow PC (R15) */
if ((insn ^ 0xffffffff) & mask)
goto reject;
break;
case REG_TYPE_NOSP:
/* Reject SP (R13) */
if (((insn ^ 0xdddddddd) & mask) == 0)
goto reject;
break;
case REG_TYPE_NOSPPC:
case REG_TYPE_NOSPPCX:
/* Reject SP and PC (R13 and R15) */
if (((insn ^ 0xdddddddd) & 0xdddddddd & mask) == 0)
goto reject;
break;
case REG_TYPE_NOPCWB:
if (!is_writeback(insn))
break; /* No writeback, so any register is OK */
/* fall through... */
case REG_TYPE_NOPC:
case REG_TYPE_NOPCX:
/* Reject PC (R15) */
if (((insn ^ 0xffffffff) & mask) == 0)
goto reject;
break;
}
/* Replace value of nibble with new register number... */
insn &= ~mask;
insn |= new_bits & mask;
}
*pinsn = insn;
return true;
reject:
return false;
}
static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
[DECODE_TYPE_TABLE] = sizeof(struct decode_table),
[DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
[DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
[DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
[DECODE_TYPE_OR] = sizeof(struct decode_or),
[DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
};
/*
* kprobe_decode_insn operates on data tables in order to decode an ARM
* architecture instruction onto which a kprobe has been placed.
*
* These instruction decoding tables are a concatenation of entries each
* of which consist of one of the following structs:
*
* decode_table
* decode_custom
* decode_simulate
* decode_emulate
* decode_or
* decode_reject
*
* Each of these starts with a struct decode_header which has the following
* fields:
*
* type_regs
* mask
* value
*
* The least significant DECODE_TYPE_BITS of type_regs contains a value
* from enum decode_type, this indicates which of the decode_* structs
* the entry contains. The value DECODE_TYPE_END indicates the end of the
* table.
*
* When the table is parsed, each entry is checked in turn to see if it
* matches the instruction to be decoded using the test:
*
* (insn & mask) == value
*
* If no match is found before the end of the table is reached then decoding
* fails with INSN_REJECTED.
*
* When a match is found, decode_regs() is called to validate and modify each
* of the registers encoded in the instruction; the data it uses to do this
* is (type_regs >> DECODE_TYPE_BITS). A validation failure will cause decoding
* to fail with INSN_REJECTED.
*
* Once the instruction has passed the above tests, further processing
* depends on the type of the table entry's decode struct.
*
*/
int __kprobes
kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
const union decode_item *table, bool thumb)
{
const struct decode_header *h = (struct decode_header *)table;
const struct decode_header *next;
bool matched = false;
insn = prepare_emulated_insn(insn, asi, thumb);
for (;; h = next) {
enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
u32 regs = h->type_regs.bits >> DECODE_TYPE_BITS;
if (type == DECODE_TYPE_END)
return INSN_REJECTED;
next = (struct decode_header *)
((uintptr_t)h + decode_struct_sizes[type]);
if (!matched && (insn & h->mask.bits) != h->value.bits)
continue;
if (!decode_regs(&insn, regs))
return INSN_REJECTED;
switch (type) {
case DECODE_TYPE_TABLE: {
struct decode_table *d = (struct decode_table *)h;
next = (struct decode_header *)d->table.table;
break;
}
case DECODE_TYPE_CUSTOM: {
struct decode_custom *d = (struct decode_custom *)h;
return (*d->decoder.decoder)(insn, asi);
}
case DECODE_TYPE_SIMULATE: {
struct decode_simulate *d = (struct decode_simulate *)h;
asi->insn_handler = d->handler.handler;
return INSN_GOOD_NO_SLOT;
}
case DECODE_TYPE_EMULATE: {
struct decode_emulate *d = (struct decode_emulate *)h;
asi->insn_handler = d->handler.handler;
set_emulated_insn(insn, asi, thumb);
return INSN_GOOD;
}
case DECODE_TYPE_OR:
matched = true;
break;
case DECODE_TYPE_REJECT:
default:
return INSN_REJECTED;
}
}
}

373
arch/arm/kernel/kprobes.h
View File

@ -52,377 +52,6 @@ enum kprobe_insn arm_kprobe_decode_insn(kprobe_opcode_t,
void __init arm_kprobe_decode_init(void);
extern kprobe_check_cc * const kprobe_condition_checks[16];
#if __LINUX_ARM_ARCH__ >= 7
/* str_pc_offset is architecturally defined from ARMv7 onwards */
#define str_pc_offset 8
#define find_str_pc_offset()
#else /* __LINUX_ARM_ARCH__ < 7 */
/* We need a run-time check to determine str_pc_offset */
extern int str_pc_offset;
void __init find_str_pc_offset(void);
#endif
/*
* Update ITSTATE after normal execution of an IT block instruction.
*
* The 8 IT state bits are split into two parts in CPSR:
* ITSTATE<1:0> are in CPSR<26:25>
* ITSTATE<7:2> are in CPSR<15:10>
*/
static inline unsigned long it_advance(unsigned long cpsr)
{
if ((cpsr & 0x06000400) == 0) {
/* ITSTATE<2:0> == 0 means end of IT block, so clear IT state */
cpsr &= ~PSR_IT_MASK;
} else {
/* We need to shift left ITSTATE<4:0> */
const unsigned long mask = 0x06001c00; /* Mask ITSTATE<4:0> */
unsigned long it = cpsr & mask;
it <<= 1;
it |= it >> (27 - 10); /* Carry ITSTATE<2> to correct place */
it &= mask;
cpsr &= ~mask;
cpsr |= it;
}
return cpsr;
}
static inline void __kprobes bx_write_pc(long pcv, struct pt_regs *regs)
{
long cpsr = regs->ARM_cpsr;
if (pcv & 0x1) {
cpsr |= PSR_T_BIT;
pcv &= ~0x1;
} else {
cpsr &= ~PSR_T_BIT;
pcv &= ~0x2; /* Avoid UNPREDICTABLE address allignment */
}
regs->ARM_cpsr = cpsr;
regs->ARM_pc = pcv;
}
#if __LINUX_ARM_ARCH__ >= 6
/* Kernels built for >= ARMv6 should never run on <= ARMv5 hardware, so... */
#define load_write_pc_interworks true
#define test_load_write_pc_interworking()
#else /* __LINUX_ARM_ARCH__ < 6 */
/* We need run-time testing to determine if load_write_pc() should interwork. */
extern bool load_write_pc_interworks;
void __init test_load_write_pc_interworking(void);
#endif
static inline void __kprobes load_write_pc(long pcv, struct pt_regs *regs)
{
if (load_write_pc_interworks)
bx_write_pc(pcv, regs);
else
regs->ARM_pc = pcv;
}
#if __LINUX_ARM_ARCH__ >= 7
#define alu_write_pc_interworks true
#define test_alu_write_pc_interworking()
#elif __LINUX_ARM_ARCH__ <= 5
/* Kernels built for <= ARMv5 should never run on >= ARMv6 hardware, so... */
#define alu_write_pc_interworks false
#define test_alu_write_pc_interworking()
#else /* __LINUX_ARM_ARCH__ == 6 */
/* We could be an ARMv6 binary on ARMv7 hardware so we need a run-time check. */
extern bool alu_write_pc_interworks;
void __init test_alu_write_pc_interworking(void);
#endif /* __LINUX_ARM_ARCH__ == 6 */
static inline void __kprobes alu_write_pc(long pcv, struct pt_regs *regs)
{
if (alu_write_pc_interworks)
bx_write_pc(pcv, regs);
else
regs->ARM_pc = pcv;
}
void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs);
void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs);
enum kprobe_insn __kprobes
kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi);
/*
* Test if load/store instructions writeback the address register.
* if P (bit 24) == 0 or W (bit 21) == 1
*/
#define is_writeback(insn) ((insn ^ 0x01000000) & 0x01200000)
/*
* The following definitions and macros are used to build instruction
* decoding tables for use by kprobe_decode_insn.
*
* These tables are a concatenation of entries each of which consist of one of
* the decode_* structs. All of the fields in every type of decode structure
* are of the union type decode_item, therefore the entire decode table can be
* viewed as an array of these and declared like:
*
* static const union decode_item table_name[] = {};
*
* In order to construct each entry in the table, macros are used to
* initialise a number of sequential decode_item values in a layout which
* matches the relevant struct. E.g. DECODE_SIMULATE initialise a struct
* decode_simulate by initialising four decode_item objects like this...
*
* {.bits = _type},
* {.bits = _mask},
* {.bits = _value},
* {.handler = _handler},
*
* Initialising a specified member of the union means that the compiler
* will produce a warning if the argument is of an incorrect type.
*
* Below is a list of each of the macros used to initialise entries and a
* description of the action performed when that entry is matched to an
* instruction. A match is found when (instruction & mask) == value.
*
* DECODE_TABLE(mask, value, table)
* Instruction decoding jumps to parsing the new sub-table 'table'.
*
* DECODE_CUSTOM(mask, value, decoder)
* The custom function 'decoder' is called to the complete decoding
* of an instruction.
*
* DECODE_SIMULATE(mask, value, handler)
* Set the probes instruction handler to 'handler', this will be used
* to simulate the instruction when the probe is hit. Decoding returns
* with INSN_GOOD_NO_SLOT.
*
* DECODE_EMULATE(mask, value, handler)
* Set the probes instruction handler to 'handler', this will be used
* to emulate the instruction when the probe is hit. The modified
* instruction (see below) is placed in the probes instruction slot so it
* may be called by the emulation code. Decoding returns with INSN_GOOD.
*
* DECODE_REJECT(mask, value)
* Instruction decoding fails with INSN_REJECTED
*
* DECODE_OR(mask, value)
* This allows the mask/value test of multiple table entries to be
* logically ORed. Once an 'or' entry is matched the decoding action to
* be performed is that of the next entry which isn't an 'or'. E.g.
*
* DECODE_OR (mask1, value1)
* DECODE_OR (mask2, value2)
* DECODE_SIMULATE (mask3, value3, simulation_handler)
*
* This means that if any of the three mask/value pairs match the
* instruction being decoded, then 'simulation_handler' will be used
* for it.
*
* Both the SIMULATE and EMULATE macros have a second form which take an
* additional 'regs' argument.
*
* DECODE_SIMULATEX(mask, value, handler, regs)
* DECODE_EMULATEX (mask, value, handler, regs)
*
* These are used to specify what kind of CPU register is encoded in each of the
* least significant 5 nibbles of the instruction being decoded. The regs value
* is specified using the REGS macro, this takes any of the REG_TYPE_* values
* from enum decode_reg_type as arguments; only the '*' part of the name is
* given. E.g.
*
* REGS(0, ANY, NOPC, 0, ANY)
*
* This indicates an instruction is encoded like:
*
* bits 19..16 ignore
* bits 15..12 any register allowed here
* bits 11.. 8 any register except PC allowed here
* bits 7.. 4 ignore
* bits 3.. 0 any register allowed here
*
* This register specification is checked after a decode table entry is found to
* match an instruction (through the mask/value test). Any invalid register then
* found in the instruction will cause decoding to fail with INSN_REJECTED. In
* the above example this would happen if bits 11..8 of the instruction were
* 1111, indicating R15 or PC.
*
* As well as checking for legal combinations of registers, this data is also
* used to modify the registers encoded in the instructions so that an
* emulation routines can use it. (See decode_regs() and INSN_NEW_BITS.)
*
* Here is a real example which matches ARM instructions of the form
* "AND <Rd>,<Rn>,<Rm>,<shift> <Rs>"
*
* DECODE_EMULATEX (0x0e000090, 0x00000010, emulate_rd12rn16rm0rs8_rwflags,
* REGS(ANY, ANY, NOPC, 0, ANY)),
* ^ ^ ^ ^
* Rn Rd Rs Rm
*
* Decoding the instruction "AND R4, R5, R6, ASL R15" will be rejected because
* Rs == R15
*
* Decoding the instruction "AND R4, R5, R6, ASL R7" will be accepted and the
* instruction will be modified to "AND R0, R2, R3, ASL R1" and then placed into
* the kprobes instruction slot. This can then be called later by the handler
* function emulate_rd12rn16rm0rs8_rwflags in order to simulate the instruction.
*/
enum decode_type {
DECODE_TYPE_END,
DECODE_TYPE_TABLE,
DECODE_TYPE_CUSTOM,
DECODE_TYPE_SIMULATE,
DECODE_TYPE_EMULATE,
DECODE_TYPE_OR,
DECODE_TYPE_REJECT,
NUM_DECODE_TYPES /* Must be last enum */
};
#define DECODE_TYPE_BITS 4
#define DECODE_TYPE_MASK ((1 << DECODE_TYPE_BITS) - 1)
enum decode_reg_type {
REG_TYPE_NONE = 0, /* Not a register, ignore */
REG_TYPE_ANY, /* Any register allowed */
REG_TYPE_SAMEAS16, /* Register should be same as that at bits 19..16 */
REG_TYPE_SP, /* Register must be SP */
REG_TYPE_PC, /* Register must be PC */
REG_TYPE_NOSP, /* Register must not be SP */
REG_TYPE_NOSPPC, /* Register must not be SP or PC */
REG_TYPE_NOPC, /* Register must not be PC */
REG_TYPE_NOPCWB, /* No PC if load/store write-back flag also set */
/* The following types are used when the encoding for PC indicates
* another instruction form. This distiction only matters for test
* case coverage checks.
*/
REG_TYPE_NOPCX, /* Register must not be PC */
REG_TYPE_NOSPPCX, /* Register must not be SP or PC */
/* Alias to allow '0' arg to be used in REGS macro. */
REG_TYPE_0 = REG_TYPE_NONE
};
#define REGS(r16, r12, r8, r4, r0) \
((REG_TYPE_##r16) << 16) + \
((REG_TYPE_##r12) << 12) + \
((REG_TYPE_##r8) << 8) + \
((REG_TYPE_##r4) << 4) + \
(REG_TYPE_##r0)
union decode_item {
u32 bits;
const union decode_item *table;
kprobe_insn_handler_t *handler;
kprobe_decode_insn_t *decoder;
};
#define DECODE_END \
{.bits = DECODE_TYPE_END}
struct decode_header {
union decode_item type_regs;
union decode_item mask;
union decode_item value;
};
#define DECODE_HEADER(_type, _mask, _value, _regs) \
{.bits = (_type) | ((_regs) << DECODE_TYPE_BITS)}, \
{.bits = (_mask)}, \
{.bits = (_value)}
struct decode_table {
struct decode_header header;
union decode_item table;
};
#define DECODE_TABLE(_mask, _value, _table) \
DECODE_HEADER(DECODE_TYPE_TABLE, _mask, _value, 0), \
{.table = (_table)}
struct decode_custom {
struct decode_header header;
union decode_item decoder;
};
#define DECODE_CUSTOM(_mask, _value, _decoder) \
DECODE_HEADER(DECODE_TYPE_CUSTOM, _mask, _value, 0), \
{.decoder = (_decoder)}
struct decode_simulate {
struct decode_header header;
union decode_item handler;
};
#define DECODE_SIMULATEX(_mask, _value, _handler, _regs) \
DECODE_HEADER(DECODE_TYPE_SIMULATE, _mask, _value, _regs), \
{.handler = (_handler)}
#define DECODE_SIMULATE(_mask, _value, _handler) \
DECODE_SIMULATEX(_mask, _value, _handler, 0)
struct decode_emulate {
struct decode_header header;
union decode_item handler;
};
#define DECODE_EMULATEX(_mask, _value, _handler, _regs) \
DECODE_HEADER(DECODE_TYPE_EMULATE, _mask, _value, _regs), \
{.handler = (_handler)}
#define DECODE_EMULATE(_mask, _value, _handler) \
DECODE_EMULATEX(_mask, _value, _handler, 0)
struct decode_or {
struct decode_header header;
};
#define DECODE_OR(_mask, _value) \
DECODE_HEADER(DECODE_TYPE_OR, _mask, _value, 0)
struct decode_reject {
struct decode_header header;
};
#define DECODE_REJECT(_mask, _value) \
DECODE_HEADER(DECODE_TYPE_REJECT, _mask, _value, 0)
#ifdef CONFIG_THUMB2_KERNEL
extern const union decode_item kprobe_decode_thumb16_table[];
extern const union decode_item kprobe_decode_thumb32_table[];
#else
extern const union decode_item kprobe_decode_arm_table[];
#endif
int kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
const union decode_item *table, bool thumb16);
#include "probes.h"
#endif /* _ARM_KERNEL_KPROBES_H */

731
arch/arm/kernel/probes-arm.c Normal file
View File

@ -0,0 +1,731 @@
/*
* arch/arm/kernel/probes-arm.c
*
* Some code moved here from arch/arm/kernel/kprobes-arm.c
*
* Copyright (C) 2006, 2007 Motorola Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/ptrace.h>
#include <linux/kprobes.h>
#include "kprobes.h"
#include "probes-arm.h"
#define sign_extend(x, signbit) ((x) | (0 - ((x) & (1 << (signbit)))))
#define branch_displacement(insn) sign_extend(((insn) & 0xffffff) << 2, 25)
/*
* To avoid the complications of mimicing single-stepping on a
* processor without a Next-PC or a single-step mode, and to
* avoid having to deal with the side-effects of boosting, we
* simulate or emulate (almost) all ARM instructions.
*
* "Simulation" is where the instruction's behavior is duplicated in
* C code. "Emulation" is where the original instruction is rewritten
* and executed, often by altering its registers.
*
* By having all behavior of the kprobe'd instruction completed before
* returning from the kprobe_handler(), all locks (scheduler and
* interrupt) can safely be released. There is no need for secondary
* breakpoints, no race with MP or preemptable kernels, nor having to
* clean up resources counts at a later time impacting overall system
* performance. By rewriting the instruction, only the minimum registers
* need to be loaded and saved back optimizing performance.
*
* Calling the insnslot_*_rwflags version of a function doesn't hurt
* anything even when the CPSR flags aren't updated by the
* instruction. It's just a little slower in return for saving
* a little space by not having a duplicate function that doesn't
* update the flags. (The same optimization can be said for
* instructions that do or don't perform register writeback)
* Also, instructions can either read the flags, only write the
* flags, or read and write the flags. To save combinations
* rather than for sheer performance, flag functions just assume
* read and write of flags.
*/
void __kprobes simulate_bbl(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int disp = branch_displacement(insn);
if (insn & (1 << 24))
regs->ARM_lr = iaddr + 4;
regs->ARM_pc = iaddr + 8 + disp;
}
void __kprobes simulate_blx1(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long iaddr = (long)p->addr;
int disp = branch_displacement(insn);
regs->ARM_lr = iaddr + 4;
regs->ARM_pc = iaddr + 8 + disp + ((insn >> 23) & 0x2);
regs->ARM_cpsr |= PSR_T_BIT;
}
void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rm = insn & 0xf;
long rmv = regs->uregs[rm];
if (insn & (1 << 5))
regs->ARM_lr = (long)p->addr + 4;
regs->ARM_pc = rmv & ~0x1;
regs->ARM_cpsr &= ~PSR_T_BIT;
if (rmv & 0x1)
regs->ARM_cpsr |= PSR_T_BIT;
}
void __kprobes simulate_mrs(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
int rd = (insn >> 12) & 0xf;
unsigned long mask = 0xf8ff03df; /* Mask out execution state */
regs->uregs[rd] = regs->ARM_cpsr & mask;
}
void __kprobes simulate_mov_ipsp(struct kprobe *p, struct pt_regs *regs)
{
regs->uregs[12] = regs->uregs[13];
}
/*
* For the instruction masking and comparisons in all the "space_*"
* functions below, Do _not_ rearrange the order of tests unless
* you're very, very sure of what you are doing. For the sake of
* efficiency, the masks for some tests sometimes assume other test
* have been done prior to them so the number of patterns to test
* for an instruction set can be as broad as possible to reduce the
* number of tests needed.
*/
static const union decode_item arm_1111_table[] = {
/* Unconditional instructions */
/* memory hint 1111 0100 x001 xxxx xxxx xxxx xxxx xxxx */
/* PLDI (immediate) 1111 0100 x101 xxxx xxxx xxxx xxxx xxxx */
/* PLDW (immediate) 1111 0101 x001 xxxx xxxx xxxx xxxx xxxx */
/* PLD (immediate) 1111 0101 x101 xxxx xxxx xxxx xxxx xxxx */
DECODE_SIMULATE (0xfe300000, 0xf4100000, kprobe_simulate_nop),
/* memory hint 1111 0110 x001 xxxx xxxx xxxx xxx0 xxxx */
/* PLDI (register) 1111 0110 x101 xxxx xxxx xxxx xxx0 xxxx */
/* PLDW (register) 1111 0111 x001 xxxx xxxx xxxx xxx0 xxxx */
/* PLD (register) 1111 0111 x101 xxxx xxxx xxxx xxx0 xxxx */
DECODE_SIMULATE (0xfe300010, 0xf6100000, kprobe_simulate_nop),
/* BLX (immediate) 1111 101x xxxx xxxx xxxx xxxx xxxx xxxx */
DECODE_SIMULATE (0xfe000000, 0xfa000000, simulate_blx1),
/* CPS 1111 0001 0000 xxx0 xxxx xxxx xx0x xxxx */
/* SETEND 1111 0001 0000 0001 xxxx xxxx 0000 xxxx */
/* SRS 1111 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
/* RFE 1111 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* Coprocessor instructions... */
/* MCRR2 1111 1100 0100 xxxx xxxx xxxx xxxx xxxx */
/* MRRC2 1111 1100 0101 xxxx xxxx xxxx xxxx xxxx */
/* LDC2 1111 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
/* STC2 1111 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
/* CDP2 1111 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
/* MCR2 1111 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
/* MRC2 1111 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
/* Other unallocated instructions... */
DECODE_END
};
static const union decode_item arm_cccc_0001_0xx0____0xxx_table[] = {
/* Miscellaneous instructions */
/* MRS cpsr cccc 0001 0000 xxxx xxxx xxxx 0000 xxxx */
DECODE_SIMULATEX(0x0ff000f0, 0x01000000, simulate_mrs,
REGS(0, NOPC, 0, 0, 0)),
/* BX cccc 0001 0010 xxxx xxxx xxxx 0001 xxxx */
DECODE_SIMULATE (0x0ff000f0, 0x01200010, simulate_blx2bx),
/* BLX (register) cccc 0001 0010 xxxx xxxx xxxx 0011 xxxx */
DECODE_SIMULATEX(0x0ff000f0, 0x01200030, simulate_blx2bx,
REGS(0, 0, 0, 0, NOPC)),
/* CLZ cccc 0001 0110 xxxx xxxx xxxx 0001 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x01600010, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* QADD cccc 0001 0000 xxxx xxxx xxxx 0101 xxxx */
/* QSUB cccc 0001 0010 xxxx xxxx xxxx 0101 xxxx */
/* QDADD cccc 0001 0100 xxxx xxxx xxxx 0101 xxxx */
/* QDSUB cccc 0001 0110 xxxx xxxx xxxx 0101 xxxx */
DECODE_EMULATEX (0x0f9000f0, 0x01000050, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* BXJ cccc 0001 0010 xxxx xxxx xxxx 0010 xxxx */
/* MSR cccc 0001 0x10 xxxx xxxx xxxx 0000 xxxx */
/* MRS spsr cccc 0001 0100 xxxx xxxx xxxx 0000 xxxx */
/* BKPT 1110 0001 0010 xxxx xxxx xxxx 0111 xxxx */
/* SMC cccc 0001 0110 xxxx xxxx xxxx 0111 xxxx */
/* And unallocated instructions... */
DECODE_END
};
static const union decode_item arm_cccc_0001_0xx0____1xx0_table[] = {
/* Halfword multiply and multiply-accumulate */
/* SMLALxy cccc 0001 0100 xxxx xxxx xxxx 1xx0 xxxx */
DECODE_EMULATEX (0x0ff00090, 0x01400080, emulate_rdlo12rdhi16rn0rm8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* SMULWy cccc 0001 0010 xxxx xxxx xxxx 1x10 xxxx */
DECODE_OR (0x0ff000b0, 0x012000a0),
/* SMULxy cccc 0001 0110 xxxx xxxx xxxx 1xx0 xxxx */
DECODE_EMULATEX (0x0ff00090, 0x01600080, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, 0, NOPC, 0, NOPC)),
/* SMLAxy cccc 0001 0000 xxxx xxxx xxxx 1xx0 xxxx */
DECODE_OR (0x0ff00090, 0x01000080),
/* SMLAWy cccc 0001 0010 xxxx xxxx xxxx 1x00 xxxx */
DECODE_EMULATEX (0x0ff000b0, 0x01200080, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_0000_____1001_table[] = {
/* Multiply and multiply-accumulate */
/* MUL cccc 0000 0000 xxxx xxxx xxxx 1001 xxxx */
/* MULS cccc 0000 0001 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0fe000f0, 0x00000090, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, 0, NOPC, 0, NOPC)),
/* MLA cccc 0000 0010 xxxx xxxx xxxx 1001 xxxx */
/* MLAS cccc 0000 0011 xxxx xxxx xxxx 1001 xxxx */
DECODE_OR (0x0fe000f0, 0x00200090),
/* MLS cccc 0000 0110 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x00600090, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* UMAAL cccc 0000 0100 xxxx xxxx xxxx 1001 xxxx */
DECODE_OR (0x0ff000f0, 0x00400090),
/* UMULL cccc 0000 1000 xxxx xxxx xxxx 1001 xxxx */
/* UMULLS cccc 0000 1001 xxxx xxxx xxxx 1001 xxxx */
/* UMLAL cccc 0000 1010 xxxx xxxx xxxx 1001 xxxx */
/* UMLALS cccc 0000 1011 xxxx xxxx xxxx 1001 xxxx */
/* SMULL cccc 0000 1100 xxxx xxxx xxxx 1001 xxxx */
/* SMULLS cccc 0000 1101 xxxx xxxx xxxx 1001 xxxx */
/* SMLAL cccc 0000 1110 xxxx xxxx xxxx 1001 xxxx */
/* SMLALS cccc 0000 1111 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0f8000f0, 0x00800090, emulate_rdlo12rdhi16rn0rm8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_0001_____1001_table[] = {
/* Synchronization primitives */
#if __LINUX_ARM_ARCH__ < 6
/* Deprecated on ARMv6 and may be UNDEFINED on v7 */
/* SMP/SWPB cccc 0001 0x00 xxxx xxxx xxxx 1001 xxxx */
DECODE_EMULATEX (0x0fb000f0, 0x01000090, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
#endif
/* LDREX/STREX{,D,B,H} cccc 0001 1xxx xxxx xxxx xxxx 1001 xxxx */
/* And unallocated instructions... */
DECODE_END
};
static const union decode_item arm_cccc_000x_____1xx1_table[] = {
/* Extra load/store instructions */
/* STRHT cccc 0000 xx10 xxxx xxxx xxxx 1011 xxxx */
/* ??? cccc 0000 xx10 xxxx xxxx xxxx 11x1 xxxx */
/* LDRHT cccc 0000 xx11 xxxx xxxx xxxx 1011 xxxx */
/* LDRSBT cccc 0000 xx11 xxxx xxxx xxxx 1101 xxxx */
/* LDRSHT cccc 0000 xx11 xxxx xxxx xxxx 1111 xxxx */
DECODE_REJECT (0x0f200090, 0x00200090),
/* LDRD/STRD lr,pc,{... cccc 000x x0x0 xxxx 111x xxxx 1101 xxxx */
DECODE_REJECT (0x0e10e0d0, 0x0000e0d0),
/* LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx */
/* STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e5000d0, 0x000000d0, emulate_ldrdstrd,
REGS(NOPCWB, NOPCX, 0, 0, NOPC)),
/* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx */
/* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e5000d0, 0x004000d0, emulate_ldrdstrd,
REGS(NOPCWB, NOPCX, 0, 0, 0)),
/* STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0e5000f0, 0x000000b0, emulate_str,
REGS(NOPCWB, NOPC, 0, 0, NOPC)),
/* LDRH (register) cccc 000x x0x1 xxxx xxxx xxxx 1011 xxxx */
/* LDRSB (register) cccc 000x x0x1 xxxx xxxx xxxx 1101 xxxx */
/* LDRSH (register) cccc 000x x0x1 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e500090, 0x00100090, emulate_ldr,
REGS(NOPCWB, NOPC, 0, 0, NOPC)),
/* STRH (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0e5000f0, 0x004000b0, emulate_str,
REGS(NOPCWB, NOPC, 0, 0, 0)),
/* LDRH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1011 xxxx */
/* LDRSB (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1101 xxxx */
/* LDRSH (immediate) cccc 000x x1x1 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0e500090, 0x00500090, emulate_ldr,
REGS(NOPCWB, NOPC, 0, 0, 0)),
DECODE_END
};
static const union decode_item arm_cccc_000x_table[] = {
/* Data-processing (register) */
/* <op>S PC, ... cccc 000x xxx1 xxxx 1111 xxxx xxxx xxxx */
DECODE_REJECT (0x0e10f000, 0x0010f000),
/* MOV IP, SP 1110 0001 1010 0000 1100 0000 0000 1101 */
DECODE_SIMULATE (0xffffffff, 0xe1a0c00d, simulate_mov_ipsp),
/* TST (register) cccc 0001 0001 xxxx xxxx xxxx xxx0 xxxx */
/* TEQ (register) cccc 0001 0011 xxxx xxxx xxxx xxx0 xxxx */
/* CMP (register) cccc 0001 0101 xxxx xxxx xxxx xxx0 xxxx */
/* CMN (register) cccc 0001 0111 xxxx xxxx xxxx xxx0 xxxx */
DECODE_EMULATEX (0x0f900010, 0x01100000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, 0, 0, 0, ANY)),
/* MOV (register) cccc 0001 101x xxxx xxxx xxxx xxx0 xxxx */
/* MVN (register) cccc 0001 111x xxxx xxxx xxxx xxx0 xxxx */
DECODE_EMULATEX (0x0fa00010, 0x01a00000, emulate_rd12rn16rm0rs8_rwflags,
REGS(0, ANY, 0, 0, ANY)),
/* AND (register) cccc 0000 000x xxxx xxxx xxxx xxx0 xxxx */
/* EOR (register) cccc 0000 001x xxxx xxxx xxxx xxx0 xxxx */
/* SUB (register) cccc 0000 010x xxxx xxxx xxxx xxx0 xxxx */
/* RSB (register) cccc 0000 011x xxxx xxxx xxxx xxx0 xxxx */
/* ADD (register) cccc 0000 100x xxxx xxxx xxxx xxx0 xxxx */
/* ADC (register) cccc 0000 101x xxxx xxxx xxxx xxx0 xxxx */
/* SBC (register) cccc 0000 110x xxxx xxxx xxxx xxx0 xxxx */
/* RSC (register) cccc 0000 111x xxxx xxxx xxxx xxx0 xxxx */
/* ORR (register) cccc 0001 100x xxxx xxxx xxxx xxx0 xxxx */
/* BIC (register) cccc 0001 110x xxxx xxxx xxxx xxx0 xxxx */
DECODE_EMULATEX (0x0e000010, 0x00000000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, ANY, 0, 0, ANY)),
/* TST (reg-shift reg) cccc 0001 0001 xxxx xxxx xxxx 0xx1 xxxx */
/* TEQ (reg-shift reg) cccc 0001 0011 xxxx xxxx xxxx 0xx1 xxxx */
/* CMP (reg-shift reg) cccc 0001 0101 xxxx xxxx xxxx 0xx1 xxxx */
/* CMN (reg-shift reg) cccc 0001 0111 xxxx xxxx xxxx 0xx1 xxxx */
DECODE_EMULATEX (0x0f900090, 0x01100010, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, 0, NOPC, 0, ANY)),
/* MOV (reg-shift reg) cccc 0001 101x xxxx xxxx xxxx 0xx1 xxxx */
/* MVN (reg-shift reg) cccc 0001 111x xxxx xxxx xxxx 0xx1 xxxx */
DECODE_EMULATEX (0x0fa00090, 0x01a00010, emulate_rd12rn16rm0rs8_rwflags,
REGS(0, ANY, NOPC, 0, ANY)),
/* AND (reg-shift reg) cccc 0000 000x xxxx xxxx xxxx 0xx1 xxxx */
/* EOR (reg-shift reg) cccc 0000 001x xxxx xxxx xxxx 0xx1 xxxx */
/* SUB (reg-shift reg) cccc 0000 010x xxxx xxxx xxxx 0xx1 xxxx */
/* RSB (reg-shift reg) cccc 0000 011x xxxx xxxx xxxx 0xx1 xxxx */
/* ADD (reg-shift reg) cccc 0000 100x xxxx xxxx xxxx 0xx1 xxxx */
/* ADC (reg-shift reg) cccc 0000 101x xxxx xxxx xxxx 0xx1 xxxx */
/* SBC (reg-shift reg) cccc 0000 110x xxxx xxxx xxxx 0xx1 xxxx */
/* RSC (reg-shift reg) cccc 0000 111x xxxx xxxx xxxx 0xx1 xxxx */
/* ORR (reg-shift reg) cccc 0001 100x xxxx xxxx xxxx 0xx1 xxxx */
/* BIC (reg-shift reg) cccc 0001 110x xxxx xxxx xxxx 0xx1 xxxx */
DECODE_EMULATEX (0x0e000090, 0x00000010, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, ANY, NOPC, 0, ANY)),
DECODE_END
};
static const union decode_item arm_cccc_001x_table[] = {
/* Data-processing (immediate) */
/* MOVW cccc 0011 0000 xxxx xxxx xxxx xxxx xxxx */
/* MOVT cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0fb00000, 0x03000000, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, 0)),
/* YIELD cccc 0011 0010 0000 xxxx xxxx 0000 0001 */
DECODE_OR (0x0fff00ff, 0x03200001),
/* SEV cccc 0011 0010 0000 xxxx xxxx 0000 0100 */
DECODE_EMULATE (0x0fff00ff, 0x03200004, kprobe_emulate_none),
/* NOP cccc 0011 0010 0000 xxxx xxxx 0000 0000 */
/* WFE cccc 0011 0010 0000 xxxx xxxx 0000 0010 */
/* WFI cccc 0011 0010 0000 xxxx xxxx 0000 0011 */
DECODE_SIMULATE (0x0fff00fc, 0x03200000, kprobe_simulate_nop),
/* DBG cccc 0011 0010 0000 xxxx xxxx ffff xxxx */
/* unallocated hints cccc 0011 0010 0000 xxxx xxxx xxxx xxxx */
/* MSR (immediate) cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0fb00000, 0x03200000),
/* <op>S PC, ... cccc 001x xxx1 xxxx 1111 xxxx xxxx xxxx */
DECODE_REJECT (0x0e10f000, 0x0210f000),
/* TST (immediate) cccc 0011 0001 xxxx xxxx xxxx xxxx xxxx */
/* TEQ (immediate) cccc 0011 0011 xxxx xxxx xxxx xxxx xxxx */
/* CMP (immediate) cccc 0011 0101 xxxx xxxx xxxx xxxx xxxx */
/* CMN (immediate) cccc 0011 0111 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0f900000, 0x03100000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, 0, 0, 0, 0)),
/* MOV (immediate) cccc 0011 101x xxxx xxxx xxxx xxxx xxxx */
/* MVN (immediate) cccc 0011 111x xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0fa00000, 0x03a00000, emulate_rd12rn16rm0rs8_rwflags,
REGS(0, ANY, 0, 0, 0)),
/* AND (immediate) cccc 0010 000x xxxx xxxx xxxx xxxx xxxx */
/* EOR (immediate) cccc 0010 001x xxxx xxxx xxxx xxxx xxxx */
/* SUB (immediate) cccc 0010 010x xxxx xxxx xxxx xxxx xxxx */
/* RSB (immediate) cccc 0010 011x xxxx xxxx xxxx xxxx xxxx */
/* ADD (immediate) cccc 0010 100x xxxx xxxx xxxx xxxx xxxx */
/* ADC (immediate) cccc 0010 101x xxxx xxxx xxxx xxxx xxxx */
/* SBC (immediate) cccc 0010 110x xxxx xxxx xxxx xxxx xxxx */
/* RSC (immediate) cccc 0010 111x xxxx xxxx xxxx xxxx xxxx */
/* ORR (immediate) cccc 0011 100x xxxx xxxx xxxx xxxx xxxx */
/* BIC (immediate) cccc 0011 110x xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e000000, 0x02000000, emulate_rd12rn16rm0rs8_rwflags,
REGS(ANY, ANY, 0, 0, 0)),
DECODE_END
};
static const union decode_item arm_cccc_0110_____xxx1_table[] = {
/* Media instructions */
/* SEL cccc 0110 1000 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x068000b0, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* SSAT cccc 0110 101x xxxx xxxx xxxx xx01 xxxx */
/* USAT cccc 0110 111x xxxx xxxx xxxx xx01 xxxx */
DECODE_OR(0x0fa00030, 0x06a00010),
/* SSAT16 cccc 0110 1010 xxxx xxxx xxxx 0011 xxxx */
/* USAT16 cccc 0110 1110 xxxx xxxx xxxx 0011 xxxx */
DECODE_EMULATEX (0x0fb000f0, 0x06a00030, emulate_rd12rn16rm0_rwflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* REV cccc 0110 1011 xxxx xxxx xxxx 0011 xxxx */
/* REV16 cccc 0110 1011 xxxx xxxx xxxx 1011 xxxx */
/* RBIT cccc 0110 1111 xxxx xxxx xxxx 0011 xxxx */
/* REVSH cccc 0110 1111 xxxx xxxx xxxx 1011 xxxx */
DECODE_EMULATEX (0x0fb00070, 0x06b00030, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* ??? cccc 0110 0x00 xxxx xxxx xxxx xxx1 xxxx */
DECODE_REJECT (0x0fb00010, 0x06000010),
/* ??? cccc 0110 0xxx xxxx xxxx xxxx 1011 xxxx */
DECODE_REJECT (0x0f8000f0, 0x060000b0),
/* ??? cccc 0110 0xxx xxxx xxxx xxxx 1101 xxxx */
DECODE_REJECT (0x0f8000f0, 0x060000d0),
/* SADD16 cccc 0110 0001 xxxx xxxx xxxx 0001 xxxx */
/* SADDSUBX cccc 0110 0001 xxxx xxxx xxxx 0011 xxxx */
/* SSUBADDX cccc 0110 0001 xxxx xxxx xxxx 0101 xxxx */
/* SSUB16 cccc 0110 0001 xxxx xxxx xxxx 0111 xxxx */
/* SADD8 cccc 0110 0001 xxxx xxxx xxxx 1001 xxxx */
/* SSUB8 cccc 0110 0001 xxxx xxxx xxxx 1111 xxxx */
/* QADD16 cccc 0110 0010 xxxx xxxx xxxx 0001 xxxx */
/* QADDSUBX cccc 0110 0010 xxxx xxxx xxxx 0011 xxxx */
/* QSUBADDX cccc 0110 0010 xxxx xxxx xxxx 0101 xxxx */
/* QSUB16 cccc 0110 0010 xxxx xxxx xxxx 0111 xxxx */
/* QADD8 cccc 0110 0010 xxxx xxxx xxxx 1001 xxxx */
/* QSUB8 cccc 0110 0010 xxxx xxxx xxxx 1111 xxxx */
/* SHADD16 cccc 0110 0011 xxxx xxxx xxxx 0001 xxxx */
/* SHADDSUBX cccc 0110 0011 xxxx xxxx xxxx 0011 xxxx */
/* SHSUBADDX cccc 0110 0011 xxxx xxxx xxxx 0101 xxxx */
/* SHSUB16 cccc 0110 0011 xxxx xxxx xxxx 0111 xxxx */
/* SHADD8 cccc 0110 0011 xxxx xxxx xxxx 1001 xxxx */
/* SHSUB8 cccc 0110 0011 xxxx xxxx xxxx 1111 xxxx */
/* UADD16 cccc 0110 0101 xxxx xxxx xxxx 0001 xxxx */
/* UADDSUBX cccc 0110 0101 xxxx xxxx xxxx 0011 xxxx */
/* USUBADDX cccc 0110 0101 xxxx xxxx xxxx 0101 xxxx */
/* USUB16 cccc 0110 0101 xxxx xxxx xxxx 0111 xxxx */
/* UADD8 cccc 0110 0101 xxxx xxxx xxxx 1001 xxxx */
/* USUB8 cccc 0110 0101 xxxx xxxx xxxx 1111 xxxx */
/* UQADD16 cccc 0110 0110 xxxx xxxx xxxx 0001 xxxx */
/* UQADDSUBX cccc 0110 0110 xxxx xxxx xxxx 0011 xxxx */
/* UQSUBADDX cccc 0110 0110 xxxx xxxx xxxx 0101 xxxx */
/* UQSUB16 cccc 0110 0110 xxxx xxxx xxxx 0111 xxxx */
/* UQADD8 cccc 0110 0110 xxxx xxxx xxxx 1001 xxxx */
/* UQSUB8 cccc 0110 0110 xxxx xxxx xxxx 1111 xxxx */
/* UHADD16 cccc 0110 0111 xxxx xxxx xxxx 0001 xxxx */
/* UHADDSUBX cccc 0110 0111 xxxx xxxx xxxx 0011 xxxx */
/* UHSUBADDX cccc 0110 0111 xxxx xxxx xxxx 0101 xxxx */
/* UHSUB16 cccc 0110 0111 xxxx xxxx xxxx 0111 xxxx */
/* UHADD8 cccc 0110 0111 xxxx xxxx xxxx 1001 xxxx */
/* UHSUB8 cccc 0110 0111 xxxx xxxx xxxx 1111 xxxx */
DECODE_EMULATEX (0x0f800010, 0x06000010, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* PKHBT cccc 0110 1000 xxxx xxxx xxxx x001 xxxx */
/* PKHTB cccc 0110 1000 xxxx xxxx xxxx x101 xxxx */
DECODE_EMULATEX (0x0ff00030, 0x06800010, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPC, NOPC, 0, 0, NOPC)),
/* ??? cccc 0110 1001 xxxx xxxx xxxx 0111 xxxx */
/* ??? cccc 0110 1101 xxxx xxxx xxxx 0111 xxxx */
DECODE_REJECT (0x0fb000f0, 0x06900070),
/* SXTB16 cccc 0110 1000 1111 xxxx xxxx 0111 xxxx */
/* SXTB cccc 0110 1010 1111 xxxx xxxx 0111 xxxx */
/* SXTH cccc 0110 1011 1111 xxxx xxxx 0111 xxxx */
/* UXTB16 cccc 0110 1100 1111 xxxx xxxx 0111 xxxx */
/* UXTB cccc 0110 1110 1111 xxxx xxxx 0111 xxxx */
/* UXTH cccc 0110 1111 1111 xxxx xxxx 0111 xxxx */
DECODE_EMULATEX (0x0f8f00f0, 0x068f0070, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* SXTAB16 cccc 0110 1000 xxxx xxxx xxxx 0111 xxxx */
/* SXTAB cccc 0110 1010 xxxx xxxx xxxx 0111 xxxx */
/* SXTAH cccc 0110 1011 xxxx xxxx xxxx 0111 xxxx */
/* UXTAB16 cccc 0110 1100 xxxx xxxx xxxx 0111 xxxx */
/* UXTAB cccc 0110 1110 xxxx xxxx xxxx 0111 xxxx */
/* UXTAH cccc 0110 1111 xxxx xxxx xxxx 0111 xxxx */
DECODE_EMULATEX (0x0f8000f0, 0x06800070, emulate_rd12rn16rm0_rwflags_nopc,
REGS(NOPCX, NOPC, 0, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_0111_____xxx1_table[] = {
/* Media instructions */
/* UNDEFINED cccc 0111 1111 xxxx xxxx xxxx 1111 xxxx */
DECODE_REJECT (0x0ff000f0, 0x07f000f0),
/* SMLALD cccc 0111 0100 xxxx xxxx xxxx 00x1 xxxx */
/* SMLSLD cccc 0111 0100 xxxx xxxx xxxx 01x1 xxxx */
DECODE_EMULATEX (0x0ff00090, 0x07400010, emulate_rdlo12rdhi16rn0rm8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* SMUAD cccc 0111 0000 xxxx 1111 xxxx 00x1 xxxx */
/* SMUSD cccc 0111 0000 xxxx 1111 xxxx 01x1 xxxx */
DECODE_OR (0x0ff0f090, 0x0700f010),
/* SMMUL cccc 0111 0101 xxxx 1111 xxxx 00x1 xxxx */
DECODE_OR (0x0ff0f0d0, 0x0750f010),
/* USAD8 cccc 0111 1000 xxxx 1111 xxxx 0001 xxxx */
DECODE_EMULATEX (0x0ff0f0f0, 0x0780f010, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, 0, NOPC, 0, NOPC)),
/* SMLAD cccc 0111 0000 xxxx xxxx xxxx 00x1 xxxx */
/* SMLSD cccc 0111 0000 xxxx xxxx xxxx 01x1 xxxx */
DECODE_OR (0x0ff00090, 0x07000010),
/* SMMLA cccc 0111 0101 xxxx xxxx xxxx 00x1 xxxx */
DECODE_OR (0x0ff000d0, 0x07500010),
/* USADA8 cccc 0111 1000 xxxx xxxx xxxx 0001 xxxx */
DECODE_EMULATEX (0x0ff000f0, 0x07800010, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPCX, NOPC, 0, NOPC)),
/* SMMLS cccc 0111 0101 xxxx xxxx xxxx 11x1 xxxx */
DECODE_EMULATEX (0x0ff000d0, 0x075000d0, emulate_rd16rn12rm0rs8_rwflags_nopc,
REGS(NOPC, NOPC, NOPC, 0, NOPC)),
/* SBFX cccc 0111 101x xxxx xxxx xxxx x101 xxxx */
/* UBFX cccc 0111 111x xxxx xxxx xxxx x101 xxxx */
DECODE_EMULATEX (0x0fa00070, 0x07a00050, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPC)),
/* BFC cccc 0111 110x xxxx xxxx xxxx x001 1111 */
DECODE_EMULATEX (0x0fe0007f, 0x07c0001f, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, 0)),
/* BFI cccc 0111 110x xxxx xxxx xxxx x001 xxxx */
DECODE_EMULATEX (0x0fe00070, 0x07c00010, emulate_rd12rm0_noflags_nopc,
REGS(0, NOPC, 0, 0, NOPCX)),
DECODE_END
};
static const union decode_item arm_cccc_01xx_table[] = {
/* Load/store word and unsigned byte */
/* LDRB/STRB pc,[...] cccc 01xx x0xx xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0c40f000, 0x0440f000),
/* STRT cccc 01x0 x010 xxxx xxxx xxxx xxxx xxxx */
/* LDRT cccc 01x0 x011 xxxx xxxx xxxx xxxx xxxx */
/* STRBT cccc 01x0 x110 xxxx xxxx xxxx xxxx xxxx */
/* LDRBT cccc 01x0 x111 xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0d200000, 0x04200000),
/* STR (immediate) cccc 010x x0x0 xxxx xxxx xxxx xxxx xxxx */
/* STRB (immediate) cccc 010x x1x0 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x04000000, emulate_str,
REGS(NOPCWB, ANY, 0, 0, 0)),
/* LDR (immediate) cccc 010x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* LDRB (immediate) cccc 010x x1x1 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x04100000, emulate_ldr,
REGS(NOPCWB, ANY, 0, 0, 0)),
/* STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx */
/* STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x06000000, emulate_str,
REGS(NOPCWB, ANY, 0, 0, NOPC)),
/* LDR (register) cccc 011x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* LDRB (register) cccc 011x x1x1 xxxx xxxx xxxx xxxx xxxx */
DECODE_EMULATEX (0x0e100000, 0x06100000, emulate_ldr,
REGS(NOPCWB, ANY, 0, 0, NOPC)),
DECODE_END
};
static const union decode_item arm_cccc_100x_table[] = {
/* Block data transfer instructions */
/* LDM cccc 100x x0x1 xxxx xxxx xxxx xxxx xxxx */
/* STM cccc 100x x0x0 xxxx xxxx xxxx xxxx xxxx */
DECODE_CUSTOM (0x0e400000, 0x08000000, kprobe_decode_ldmstm),
/* STM (user registers) cccc 100x x1x0 xxxx xxxx xxxx xxxx xxxx */
/* LDM (user registers) cccc 100x x1x1 xxxx 0xxx xxxx xxxx xxxx */
/* LDM (exception ret) cccc 100x x1x1 xxxx 1xxx xxxx xxxx xxxx */
DECODE_END
};
const union decode_item kprobe_decode_arm_table[] = {
/*
* Unconditional instructions
* 1111 xxxx xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0xf0000000, 0xf0000000, arm_1111_table),
/*
* Miscellaneous instructions
* cccc 0001 0xx0 xxxx xxxx xxxx 0xxx xxxx
*/
DECODE_TABLE (0x0f900080, 0x01000000, arm_cccc_0001_0xx0____0xxx_table),
/*
* Halfword multiply and multiply-accumulate
* cccc 0001 0xx0 xxxx xxxx xxxx 1xx0 xxxx
*/
DECODE_TABLE (0x0f900090, 0x01000080, arm_cccc_0001_0xx0____1xx0_table),
/*
* Multiply and multiply-accumulate
* cccc 0000 xxxx xxxx xxxx xxxx 1001 xxxx
*/
DECODE_TABLE (0x0f0000f0, 0x00000090, arm_cccc_0000_____1001_table),
/*
* Synchronization primitives
* cccc 0001 xxxx xxxx xxxx xxxx 1001 xxxx
*/
DECODE_TABLE (0x0f0000f0, 0x01000090, arm_cccc_0001_____1001_table),
/*
* Extra load/store instructions
* cccc 000x xxxx xxxx xxxx xxxx 1xx1 xxxx
*/
DECODE_TABLE (0x0e000090, 0x00000090, arm_cccc_000x_____1xx1_table),
/*
* Data-processing (register)
* cccc 000x xxxx xxxx xxxx xxxx xxx0 xxxx
* Data-processing (register-shifted register)
* cccc 000x xxxx xxxx xxxx xxxx 0xx1 xxxx
*/
DECODE_TABLE (0x0e000000, 0x00000000, arm_cccc_000x_table),
/*
* Data-processing (immediate)
* cccc 001x xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0x0e000000, 0x02000000, arm_cccc_001x_table),
/*
* Media instructions
* cccc 011x xxxx xxxx xxxx xxxx xxx1 xxxx
*/
DECODE_TABLE (0x0f000010, 0x06000010, arm_cccc_0110_____xxx1_table),
DECODE_TABLE (0x0f000010, 0x07000010, arm_cccc_0111_____xxx1_table),
/*
* Load/store word and unsigned byte
* cccc 01xx xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0x0c000000, 0x04000000, arm_cccc_01xx_table),
/*
* Block data transfer instructions
* cccc 100x xxxx xxxx xxxx xxxx xxxx xxxx
*/
DECODE_TABLE (0x0e000000, 0x08000000, arm_cccc_100x_table),
/* B cccc 1010 xxxx xxxx xxxx xxxx xxxx xxxx */
/* BL cccc 1011 xxxx xxxx xxxx xxxx xxxx xxxx */
DECODE_SIMULATE (0x0e000000, 0x0a000000, simulate_bbl),
/*
* Supervisor Call, and coprocessor instructions
*/
/* MCRR cccc 1100 0100 xxxx xxxx xxxx xxxx xxxx */
/* MRRC cccc 1100 0101 xxxx xxxx xxxx xxxx xxxx */
/* LDC cccc 110x xxx1 xxxx xxxx xxxx xxxx xxxx */
/* STC cccc 110x xxx0 xxxx xxxx xxxx xxxx xxxx */
/* CDP cccc 1110 xxxx xxxx xxxx xxxx xxx0 xxxx */
/* MCR cccc 1110 xxx0 xxxx xxxx xxxx xxx1 xxxx */
/* MRC cccc 1110 xxx1 xxxx xxxx xxxx xxx1 xxxx */
/* SVC cccc 1111 xxxx xxxx xxxx xxxx xxxx xxxx */
DECODE_REJECT (0x0c000000, 0x0c000000),
DECODE_END
};
#ifdef CONFIG_ARM_KPROBES_TEST_MODULE
EXPORT_SYMBOL_GPL(kprobe_decode_arm_table);
#endif
static void __kprobes arm_singlestep(struct kprobe *p, struct pt_regs *regs)
{
regs->ARM_pc += 4;
p->ainsn.insn_handler(p, regs);
}
/* Return:
* INSN_REJECTED If instruction is one not allowed to kprobe,
* INSN_GOOD If instruction is supported and uses instruction slot,
* INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
*
* For instructions we don't want to kprobe (INSN_REJECTED return result):
* These are generally ones that modify the processor state making
* them "hard" to simulate such as switches processor modes or
* make accesses in alternate modes. Any of these could be simulated
* if the work was put into it, but low return considering they
* should also be very rare.
*/
enum kprobe_insn __kprobes
arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
{
asi->insn_singlestep = arm_singlestep;
asi->insn_check_cc = kprobe_condition_checks[insn>>28];
return kprobe_decode_insn(insn, asi, kprobe_decode_arm_table, false);
}

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/*
* arch/arm/kernel/probes-arm.h
*
* Copyright 2013 Linaro Ltd.
* Written by: David A. Long
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#ifndef _ARM_KERNEL_PROBES_ARM_H
#define _ARM_KERNEL_PROBES_ARM_H
void __kprobes simulate_bbl(struct kprobe *p, struct pt_regs *regs);
void __kprobes simulate_blx1(struct kprobe *p, struct pt_regs *regs);
void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs);
void __kprobes simulate_mrs(struct kprobe *p, struct pt_regs *regs);
void __kprobes simulate_mov_ipsp(struct kprobe *p, struct pt_regs *regs);
void __kprobes emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs);
void __kprobes emulate_ldr(struct kprobe *p, struct pt_regs *regs);
void __kprobes emulate_str(struct kprobe *p, struct pt_regs *regs);
void __kprobes emulate_rd12rn16rm0rs8_rwflags(struct kprobe *p,
struct pt_regs *regs);
void __kprobes emulate_rd12rn16rm0_rwflags_nopc(struct kprobe *p,
struct pt_regs *regs);
void __kprobes emulate_rd16rn12rm0rs8_rwflags_nopc(struct kprobe *p,
struct pt_regs *regs);
void __kprobes emulate_rd12rm0_noflags_nopc(struct kprobe *p,
struct pt_regs *regs);
void __kprobes emulate_rdlo12rdhi16rn0rm8_rwflags_nopc(struct kprobe *p,
struct pt_regs *regs);
#endif

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/*
* arch/arm/kernel/probes.c
*
* Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
*
* Some contents moved here from arch/arm/include/asm/kprobes-arm.c which is
* Copyright (C) 2006, 2007 Motorola Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/kprobes.h>
#include <asm/system_info.h>
#include <asm/ptrace.h>
#include <linux/bug.h>
#include "kprobes.h"
#ifndef find_str_pc_offset
/*
* For STR and STM instructions, an ARM core may choose to use either
* a +8 or a +12 displacement from the current instruction's address.
* Whichever value is chosen for a given core, it must be the same for
* both instructions and may not change. This function measures it.
*/
int str_pc_offset;
void __init find_str_pc_offset(void)
{
int addr, scratch, ret;
__asm__ (
"sub %[ret], pc, #4 \n\t"
"str pc, %[addr] \n\t"
"ldr %[scr], %[addr] \n\t"
"sub %[ret], %[scr], %[ret] \n\t"
: [ret] "=r" (ret), [scr] "=r" (scratch), [addr] "+m" (addr));
str_pc_offset = ret;
}
#endif /* !find_str_pc_offset */
#ifndef test_load_write_pc_interworking
bool load_write_pc_interworks;
void __init test_load_write_pc_interworking(void)
{
int arch = cpu_architecture();
BUG_ON(arch == CPU_ARCH_UNKNOWN);
load_write_pc_interworks = arch >= CPU_ARCH_ARMv5T;
}
#endif /* !test_load_write_pc_interworking */
#ifndef test_alu_write_pc_interworking
bool alu_write_pc_interworks;
void __init test_alu_write_pc_interworking(void)
{
int arch = cpu_architecture();
BUG_ON(arch == CPU_ARCH_UNKNOWN);
alu_write_pc_interworks = arch >= CPU_ARCH_ARMv7;
}
#endif /* !test_alu_write_pc_interworking */
void __init arm_kprobe_decode_init(void)
{
find_str_pc_offset();
test_load_write_pc_interworking();
test_alu_write_pc_interworking();
}
static unsigned long __kprobes __check_eq(unsigned long cpsr)
{
return cpsr & PSR_Z_BIT;
}
static unsigned long __kprobes __check_ne(unsigned long cpsr)
{
return (~cpsr) & PSR_Z_BIT;
}
static unsigned long __kprobes __check_cs(unsigned long cpsr)
{
return cpsr & PSR_C_BIT;
}
static unsigned long __kprobes __check_cc(unsigned long cpsr)
{
return (~cpsr) & PSR_C_BIT;
}
static unsigned long __kprobes __check_mi(unsigned long cpsr)
{
return cpsr & PSR_N_BIT;
}
static unsigned long __kprobes __check_pl(unsigned long cpsr)
{
return (~cpsr) & PSR_N_BIT;
}
static unsigned long __kprobes __check_vs(unsigned long cpsr)
{
return cpsr & PSR_V_BIT;
}
static unsigned long __kprobes __check_vc(unsigned long cpsr)
{
return (~cpsr) & PSR_V_BIT;
}
static unsigned long __kprobes __check_hi(unsigned long cpsr)
{
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return cpsr & PSR_C_BIT;
}
static unsigned long __kprobes __check_ls(unsigned long cpsr)
{
cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
return (~cpsr) & PSR_C_BIT;
}
static unsigned long __kprobes __check_ge(unsigned long cpsr)
{
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return (~cpsr) & PSR_N_BIT;
}
static unsigned long __kprobes __check_lt(unsigned long cpsr)
{
cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
return cpsr & PSR_N_BIT;
}
static unsigned long __kprobes __check_gt(unsigned long cpsr)
{
unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return (~temp) & PSR_N_BIT;
}
static unsigned long __kprobes __check_le(unsigned long cpsr)
{
unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
return temp & PSR_N_BIT;
}
static unsigned long __kprobes __check_al(unsigned long cpsr)
{
return true;
}
kprobe_check_cc * const kprobe_condition_checks[16] = {
&__check_eq, &__check_ne, &__check_cs, &__check_cc,
&__check_mi, &__check_pl, &__check_vs, &__check_vc,
&__check_hi, &__check_ls, &__check_ge, &__check_lt,
&__check_gt, &__check_le, &__check_al, &__check_al
};
void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs)
{
}
void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs)
{
p->ainsn.insn_fn();
}
/*
* Prepare an instruction slot to receive an instruction for emulating.
* This is done by placing a subroutine return after the location where the
* instruction will be placed. We also modify ARM instructions to be
* unconditional as the condition code will already be checked before any
* emulation handler is called.
*/
static kprobe_opcode_t __kprobes
prepare_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
bool thumb)
{
#ifdef CONFIG_THUMB2_KERNEL
if (thumb) {
u16 *thumb_insn = (u16 *)asi->insn;
thumb_insn[1] = 0x4770; /* Thumb bx lr */
thumb_insn[2] = 0x4770; /* Thumb bx lr */
return insn;
}
asi->insn[1] = 0xe12fff1e; /* ARM bx lr */
#else
asi->insn[1] = 0xe1a0f00e; /* mov pc, lr */
#endif
/* Make an ARM instruction unconditional */
if (insn < 0xe0000000)
insn = (insn | 0xe0000000) & ~0x10000000;
return insn;
}
/*
* Write a (probably modified) instruction into the slot previously prepared by
* prepare_emulated_insn
*/
static void __kprobes
set_emulated_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
bool thumb)
{
#ifdef CONFIG_THUMB2_KERNEL
if (thumb) {
u16 *ip = (u16 *)asi->insn;
if (is_wide_instruction(insn))
*ip++ = insn >> 16;
*ip++ = insn;
return;
}
#endif
asi->insn[0] = insn;
}
/*
* When we modify the register numbers encoded in an instruction to be emulated,
* the new values come from this define. For ARM and 32-bit Thumb instructions
* this gives...
*
* bit position 16 12 8 4 0
* ---------------+---+---+---+---+---+
* register r2 r0 r1 -- r3
*/
#define INSN_NEW_BITS 0x00020103
/* Each nibble has same value as that at INSN_NEW_BITS bit 16 */
#define INSN_SAMEAS16_BITS 0x22222222
/*
* Validate and modify each of the registers encoded in an instruction.
*
* Each nibble in regs contains a value from enum decode_reg_type. For each
* non-zero value, the corresponding nibble in pinsn is validated and modified
* according to the type.
*/
static bool __kprobes decode_regs(kprobe_opcode_t *pinsn, u32 regs)
{
kprobe_opcode_t insn = *pinsn;
kprobe_opcode_t mask = 0xf; /* Start at least significant nibble */
for (; regs != 0; regs >>= 4, mask <<= 4) {
kprobe_opcode_t new_bits = INSN_NEW_BITS;
switch (regs & 0xf) {
case REG_TYPE_NONE:
/* Nibble not a register, skip to next */
continue;
case REG_TYPE_ANY:
/* Any register is allowed */
break;
case REG_TYPE_SAMEAS16:
/* Replace register with same as at bit position 16 */
new_bits = INSN_SAMEAS16_BITS;
break;
case REG_TYPE_SP:
/* Only allow SP (R13) */
if ((insn ^ 0xdddddddd) & mask)
goto reject;
break;
case REG_TYPE_PC:
/* Only allow PC (R15) */
if ((insn ^ 0xffffffff) & mask)
goto reject;
break;
case REG_TYPE_NOSP:
/* Reject SP (R13) */
if (((insn ^ 0xdddddddd) & mask) == 0)
goto reject;
break;
case REG_TYPE_NOSPPC:
case REG_TYPE_NOSPPCX:
/* Reject SP and PC (R13 and R15) */
if (((insn ^ 0xdddddddd) & 0xdddddddd & mask) == 0)
goto reject;
break;
case REG_TYPE_NOPCWB:
if (!is_writeback(insn))
break; /* No writeback, so any register is OK */
/* fall through... */
case REG_TYPE_NOPC:
case REG_TYPE_NOPCX:
/* Reject PC (R15) */
if (((insn ^ 0xffffffff) & mask) == 0)
goto reject;
break;
}
/* Replace value of nibble with new register number... */
insn &= ~mask;
insn |= new_bits & mask;
}
*pinsn = insn;
return true;
reject:
return false;
}
static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
[DECODE_TYPE_TABLE] = sizeof(struct decode_table),
[DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
[DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
[DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
[DECODE_TYPE_OR] = sizeof(struct decode_or),
[DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
};
/*
* kprobe_decode_insn operates on data tables in order to decode an ARM
* architecture instruction onto which a kprobe has been placed.
*
* These instruction decoding tables are a concatenation of entries each
* of which consist of one of the following structs:
*
* decode_table
* decode_custom
* decode_simulate
* decode_emulate
* decode_or
* decode_reject
*
* Each of these starts with a struct decode_header which has the following
* fields:
*
* type_regs
* mask
* value
*
* The least significant DECODE_TYPE_BITS of type_regs contains a value
* from enum decode_type, this indicates which of the decode_* structs
* the entry contains. The value DECODE_TYPE_END indicates the end of the
* table.
*
* When the table is parsed, each entry is checked in turn to see if it
* matches the instruction to be decoded using the test:
*
* (insn & mask) == value
*
* If no match is found before the end of the table is reached then decoding
* fails with INSN_REJECTED.
*
* When a match is found, decode_regs() is called to validate and modify each
* of the registers encoded in the instruction; the data it uses to do this
* is (type_regs >> DECODE_TYPE_BITS). A validation failure will cause decoding
* to fail with INSN_REJECTED.
*
* Once the instruction has passed the above tests, further processing
* depends on the type of the table entry's decode struct.
*
*/
int __kprobes
kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
const union decode_item *table, bool thumb)
{
const struct decode_header *h = (struct decode_header *)table;
const struct decode_header *next;
bool matched = false;
insn = prepare_emulated_insn(insn, asi, thumb);
for (;; h = next) {
enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
u32 regs = h->type_regs.bits >> DECODE_TYPE_BITS;
if (type == DECODE_TYPE_END)
return INSN_REJECTED;
next = (struct decode_header *)
((uintptr_t)h + decode_struct_sizes[type]);
if (!matched && (insn & h->mask.bits) != h->value.bits)
continue;
if (!decode_regs(&insn, regs))
return INSN_REJECTED;
switch (type) {
case DECODE_TYPE_TABLE: {
struct decode_table *d = (struct decode_table *)h;
next = (struct decode_header *)d->table.table;
break;
}
case DECODE_TYPE_CUSTOM: {
struct decode_custom *d = (struct decode_custom *)h;
return (*d->decoder.decoder)(insn, asi);
}
case DECODE_TYPE_SIMULATE: {
struct decode_simulate *d = (struct decode_simulate *)h;
asi->insn_handler = d->handler.handler;
return INSN_GOOD_NO_SLOT;
}
case DECODE_TYPE_EMULATE: {
struct decode_emulate *d = (struct decode_emulate *)h;
asi->insn_handler = d->handler.handler;
set_emulated_insn(insn, asi, thumb);
return INSN_GOOD;
}
case DECODE_TYPE_OR:
matched = true;
break;
case DECODE_TYPE_REJECT:
default:
return INSN_REJECTED;
}
}
}

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/*
* arch/arm/kernel/probes.h
*
* Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
*
* Some contents moved here from arch/arm/include/asm/kprobes.h which is
* Copyright (C) 2006, 2007 Motorola Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#ifndef _ARM_KERNEL_PROBES_H
#define _ARM_KERNEL_PROBES_H
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/kprobes.h>
#if __LINUX_ARM_ARCH__ >= 7
/* str_pc_offset is architecturally defined from ARMv7 onwards */
#define str_pc_offset 8
#define find_str_pc_offset()
#else /* __LINUX_ARM_ARCH__ < 7 */
/* We need a run-time check to determine str_pc_offset */
extern int str_pc_offset;
void __init find_str_pc_offset(void);
#endif
/*
* Update ITSTATE after normal execution of an IT block instruction.
*
* The 8 IT state bits are split into two parts in CPSR:
* ITSTATE<1:0> are in CPSR<26:25>
* ITSTATE<7:2> are in CPSR<15:10>
*/
static inline unsigned long it_advance(unsigned long cpsr)
{
if ((cpsr & 0x06000400) == 0) {
/* ITSTATE<2:0> == 0 means end of IT block, so clear IT state */
cpsr &= ~PSR_IT_MASK;
} else {
/* We need to shift left ITSTATE<4:0> */
const unsigned long mask = 0x06001c00; /* Mask ITSTATE<4:0> */
unsigned long it = cpsr & mask;
it <<= 1;
it |= it >> (27 - 10); /* Carry ITSTATE<2> to correct place */
it &= mask;
cpsr &= ~mask;
cpsr |= it;
}
return cpsr;
}
static inline void __kprobes bx_write_pc(long pcv, struct pt_regs *regs)
{
long cpsr = regs->ARM_cpsr;
if (pcv & 0x1) {
cpsr |= PSR_T_BIT;
pcv &= ~0x1;
} else {
cpsr &= ~PSR_T_BIT;
pcv &= ~0x2; /* Avoid UNPREDICTABLE address allignment */
}
regs->ARM_cpsr = cpsr;
regs->ARM_pc = pcv;
}
#if __LINUX_ARM_ARCH__ >= 6
/* Kernels built for >= ARMv6 should never run on <= ARMv5 hardware, so... */
#define load_write_pc_interworks true
#define test_load_write_pc_interworking()
#else /* __LINUX_ARM_ARCH__ < 6 */
/* We need run-time testing to determine if load_write_pc() should interwork. */
extern bool load_write_pc_interworks;
void __init test_load_write_pc_interworking(void);
#endif
static inline void __kprobes load_write_pc(long pcv, struct pt_regs *regs)
{
if (load_write_pc_interworks)
bx_write_pc(pcv, regs);
else
regs->ARM_pc = pcv;
}
#if __LINUX_ARM_ARCH__ >= 7
#define alu_write_pc_interworks true
#define test_alu_write_pc_interworking()
#elif __LINUX_ARM_ARCH__ <= 5
/* Kernels built for <= ARMv5 should never run on >= ARMv6 hardware, so... */
#define alu_write_pc_interworks false
#define test_alu_write_pc_interworking()
#else /* __LINUX_ARM_ARCH__ == 6 */
/* We could be an ARMv6 binary on ARMv7 hardware so we need a run-time check. */
extern bool alu_write_pc_interworks;
void __init test_alu_write_pc_interworking(void);
#endif /* __LINUX_ARM_ARCH__ == 6 */
static inline void __kprobes alu_write_pc(long pcv, struct pt_regs *regs)
{
if (alu_write_pc_interworks)
bx_write_pc(pcv, regs);
else
regs->ARM_pc = pcv;
}
void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs);
void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs);
enum kprobe_insn __kprobes
kprobe_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi);
/*
* Test if load/store instructions writeback the address register.
* if P (bit 24) == 0 or W (bit 21) == 1
*/
#define is_writeback(insn) ((insn ^ 0x01000000) & 0x01200000)
/*
* The following definitions and macros are used to build instruction
* decoding tables for use by kprobe_decode_insn.
*
* These tables are a concatenation of entries each of which consist of one of
* the decode_* structs. All of the fields in every type of decode structure
* are of the union type decode_item, therefore the entire decode table can be
* viewed as an array of these and declared like:
*
* static const union decode_item table_name[] = {};
*
* In order to construct each entry in the table, macros are used to
* initialise a number of sequential decode_item values in a layout which
* matches the relevant struct. E.g. DECODE_SIMULATE initialise a struct
* decode_simulate by initialising four decode_item objects like this...
*
* {.bits = _type},
* {.bits = _mask},
* {.bits = _value},
* {.handler = _handler},
*
* Initialising a specified member of the union means that the compiler
* will produce a warning if the argument is of an incorrect type.
*
* Below is a list of each of the macros used to initialise entries and a
* description of the action performed when that entry is matched to an
* instruction. A match is found when (instruction & mask) == value.
*
* DECODE_TABLE(mask, value, table)
* Instruction decoding jumps to parsing the new sub-table 'table'.
*
* DECODE_CUSTOM(mask, value, decoder)
* The custom function 'decoder' is called to the complete decoding
* of an instruction.
*
* DECODE_SIMULATE(mask, value, handler)
* Set the probes instruction handler to 'handler', this will be used
* to simulate the instruction when the probe is hit. Decoding returns
* with INSN_GOOD_NO_SLOT.
*
* DECODE_EMULATE(mask, value, handler)
* Set the probes instruction handler to 'handler', this will be used
* to emulate the instruction when the probe is hit. The modified
* instruction (see below) is placed in the probes instruction slot so it
* may be called by the emulation code. Decoding returns with INSN_GOOD.
*
* DECODE_REJECT(mask, value)
* Instruction decoding fails with INSN_REJECTED
*
* DECODE_OR(mask, value)
* This allows the mask/value test of multiple table entries to be
* logically ORed. Once an 'or' entry is matched the decoding action to
* be performed is that of the next entry which isn't an 'or'. E.g.
*
* DECODE_OR (mask1, value1)
* DECODE_OR (mask2, value2)
* DECODE_SIMULATE (mask3, value3, simulation_handler)
*
* This means that if any of the three mask/value pairs match the
* instruction being decoded, then 'simulation_handler' will be used
* for it.
*
* Both the SIMULATE and EMULATE macros have a second form which take an
* additional 'regs' argument.
*
* DECODE_SIMULATEX(mask, value, handler, regs)
* DECODE_EMULATEX (mask, value, handler, regs)
*
* These are used to specify what kind of CPU register is encoded in each of the
* least significant 5 nibbles of the instruction being decoded. The regs value
* is specified using the REGS macro, this takes any of the REG_TYPE_* values
* from enum decode_reg_type as arguments; only the '*' part of the name is
* given. E.g.
*
* REGS(0, ANY, NOPC, 0, ANY)
*
* This indicates an instruction is encoded like:
*
* bits 19..16 ignore
* bits 15..12 any register allowed here
* bits 11.. 8 any register except PC allowed here
* bits 7.. 4 ignore
* bits 3.. 0 any register allowed here
*
* This register specification is checked after a decode table entry is found to
* match an instruction (through the mask/value test). Any invalid register then
* found in the instruction will cause decoding to fail with INSN_REJECTED. In
* the above example this would happen if bits 11..8 of the instruction were
* 1111, indicating R15 or PC.
*
* As well as checking for legal combinations of registers, this data is also
* used to modify the registers encoded in the instructions so that an
* emulation routines can use it. (See decode_regs() and INSN_NEW_BITS.)
*
* Here is a real example which matches ARM instructions of the form
* "AND <Rd>,<Rn>,<Rm>,<shift> <Rs>"
*
* DECODE_EMULATEX (0x0e000090, 0x00000010, emulate_rd12rn16rm0rs8_rwflags,
* REGS(ANY, ANY, NOPC, 0, ANY)),
* ^ ^ ^ ^
* Rn Rd Rs Rm
*
* Decoding the instruction "AND R4, R5, R6, ASL R15" will be rejected because
* Rs == R15
*
* Decoding the instruction "AND R4, R5, R6, ASL R7" will be accepted and the
* instruction will be modified to "AND R0, R2, R3, ASL R1" and then placed into
* the kprobes instruction slot. This can then be called later by the handler
* function emulate_rd12rn16rm0rs8_rwflags in order to simulate the instruction.
*/
enum decode_type {
DECODE_TYPE_END,
DECODE_TYPE_TABLE,
DECODE_TYPE_CUSTOM,
DECODE_TYPE_SIMULATE,
DECODE_TYPE_EMULATE,
DECODE_TYPE_OR,
DECODE_TYPE_REJECT,
NUM_DECODE_TYPES /* Must be last enum */
};
#define DECODE_TYPE_BITS 4
#define DECODE_TYPE_MASK ((1 << DECODE_TYPE_BITS) - 1)
enum decode_reg_type {
REG_TYPE_NONE = 0, /* Not a register, ignore */
REG_TYPE_ANY, /* Any register allowed */
REG_TYPE_SAMEAS16, /* Register should be same as that at bits 19..16 */
REG_TYPE_SP, /* Register must be SP */
REG_TYPE_PC, /* Register must be PC */
REG_TYPE_NOSP, /* Register must not be SP */
REG_TYPE_NOSPPC, /* Register must not be SP or PC */
REG_TYPE_NOPC, /* Register must not be PC */
REG_TYPE_NOPCWB, /* No PC if load/store write-back flag also set */
/* The following types are used when the encoding for PC indicates
* another instruction form. This distiction only matters for test
* case coverage checks.
*/
REG_TYPE_NOPCX, /* Register must not be PC */
REG_TYPE_NOSPPCX, /* Register must not be SP or PC */
/* Alias to allow '0' arg to be used in REGS macro. */
REG_TYPE_0 = REG_TYPE_NONE
};
#define REGS(r16, r12, r8, r4, r0) \
(((REG_TYPE_##r16) << 16) + \
((REG_TYPE_##r12) << 12) + \
((REG_TYPE_##r8) << 8) + \
((REG_TYPE_##r4) << 4) + \
(REG_TYPE_##r0))
union decode_item {
u32 bits;
const union decode_item *table;
kprobe_insn_handler_t *handler;
kprobe_decode_insn_t *decoder;
};
#define DECODE_END \
{.bits = DECODE_TYPE_END}
struct decode_header {
union decode_item type_regs;
union decode_item mask;
union decode_item value;
};
#define DECODE_HEADER(_type, _mask, _value, _regs) \
{.bits = (_type) | ((_regs) << DECODE_TYPE_BITS)}, \
{.bits = (_mask)}, \
{.bits = (_value)}
struct decode_table {
struct decode_header header;
union decode_item table;
};
#define DECODE_TABLE(_mask, _value, _table) \
DECODE_HEADER(DECODE_TYPE_TABLE, _mask, _value, 0), \
{.table = (_table)}
struct decode_custom {
struct decode_header header;
union decode_item decoder;
};
#define DECODE_CUSTOM(_mask, _value, _decoder) \
DECODE_HEADER(DECODE_TYPE_CUSTOM, _mask, _value, 0), \
{.decoder = (_decoder)}
struct decode_simulate {
struct decode_header header;
union decode_item handler;
};
#define DECODE_SIMULATEX(_mask, _value, _handler, _regs) \
DECODE_HEADER(DECODE_TYPE_SIMULATE, _mask, _value, _regs), \
{.handler = (_handler)}
#define DECODE_SIMULATE(_mask, _value, _handler) \
DECODE_SIMULATEX(_mask, _value, _handler, 0)
struct decode_emulate {
struct decode_header header;
union decode_item handler;
};
#define DECODE_EMULATEX(_mask, _value, _handler, _regs) \
DECODE_HEADER(DECODE_TYPE_EMULATE, _mask, _value, _regs), \
{.handler = (_handler)}
#define DECODE_EMULATE(_mask, _value, _handler) \
DECODE_EMULATEX(_mask, _value, _handler, 0)
struct decode_or {
struct decode_header header;
};
#define DECODE_OR(_mask, _value) \
DECODE_HEADER(DECODE_TYPE_OR, _mask, _value, 0)
struct decode_reject {
struct decode_header header;
};
#define DECODE_REJECT(_mask, _value) \
DECODE_HEADER(DECODE_TYPE_REJECT, _mask, _value, 0)
#ifdef CONFIG_THUMB2_KERNEL
extern const union decode_item kprobe_decode_thumb16_table[];
extern const union decode_item kprobe_decode_thumb32_table[];
#else
extern const union decode_item kprobe_decode_arm_table[];
#endif
extern kprobe_check_cc * const kprobe_condition_checks[16];
int kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi,
const union decode_item *table, bool thumb16);
#endif