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linux/arch/mips/kernel/unaligned.c

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/*
* Handle unaligned accesses by emulation.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2014 Imagination Technologies Ltd.
*
* This file contains exception handler for address error exception with the
* special capability to execute faulting instructions in software. The
* handler does not try to handle the case when the program counter points
* to an address not aligned to a word boundary.
*
* Putting data to unaligned addresses is a bad practice even on Intel where
* only the performance is affected. Much worse is that such code is non-
* portable. Due to several programs that die on MIPS due to alignment
* problems I decided to implement this handler anyway though I originally
* didn't intend to do this at all for user code.
*
* For now I enable fixing of address errors by default to make life easier.
* I however intend to disable this somewhen in the future when the alignment
* problems with user programs have been fixed. For programmers this is the
* right way to go.
*
* Fixing address errors is a per process option. The option is inherited
* across fork(2) and execve(2) calls. If you really want to use the
* option in your user programs - I discourage the use of the software
* emulation strongly - use the following code in your userland stuff:
*
* #include <sys/sysmips.h>
*
* ...
* sysmips(MIPS_FIXADE, x);
* ...
*
* The argument x is 0 for disabling software emulation, enabled otherwise.
*
* Below a little program to play around with this feature.
*
* #include <stdio.h>
* #include <sys/sysmips.h>
*
* struct foo {
* unsigned char bar[8];
* };
*
* main(int argc, char *argv[])
* {
* struct foo x = {0, 1, 2, 3, 4, 5, 6, 7};
* unsigned int *p = (unsigned int *) (x.bar + 3);
* int i;
*
* if (argc > 1)
* sysmips(MIPS_FIXADE, atoi(argv[1]));
*
* printf("*p = %08lx\n", *p);
*
* *p = 0xdeadface;
*
* for(i = 0; i <= 7; i++)
* printf("%02x ", x.bar[i]);
* printf("\n");
* }
*
* Coprocessor loads are not supported; I think this case is unimportant
* in the practice.
*
* TODO: Handle ndc (attempted store to doubleword in uncached memory)
* exception for the R6000.
* A store crossing a page boundary might be executed only partially.
* Undo the partial store in this case.
*/
#include <linux/context_tracking.h>
#include <linux/mm.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <linux/perf_event.h>
#include <asm/asm.h>
#include <asm/branch.h>
#include <asm/byteorder.h>
#include <asm/cop2.h>
#include <asm/debug.h>
#include <asm/fpu.h>
#include <asm/fpu_emulator.h>
#include <asm/inst.h>
#include <asm/unaligned-emul.h>
#include <asm/mmu_context.h>
#include <linux/uaccess.h>
#include "access-helper.h"
enum {
UNALIGNED_ACTION_QUIET,
UNALIGNED_ACTION_SIGNAL,
UNALIGNED_ACTION_SHOW,
};
#ifdef CONFIG_DEBUG_FS
static u32 unaligned_instructions;
static u32 unaligned_action;
#else
#define unaligned_action UNALIGNED_ACTION_QUIET
#endif
extern void show_registers(struct pt_regs *regs);
static void emulate_load_store_insn(struct pt_regs *regs,
void __user *addr, unsigned int *pc)
{
unsigned long origpc, orig31, value;
union mips_instruction insn;
unsigned int res;
bool user = user_mode(regs);
origpc = (unsigned long)pc;
orig31 = regs->regs[31];
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0);
/*
* This load never faults.
*/
__get_inst32(&insn.word, pc, user);
switch (insn.i_format.opcode) {
/*
* These are instructions that a compiler doesn't generate. We
* can assume therefore that the code is MIPS-aware and
* really buggy. Emulating these instructions would break the
* semantics anyway.
*/
case ll_op:
case lld_op:
case sc_op:
case scd_op:
/*
* For these instructions the only way to create an address
* error is an attempted access to kernel/supervisor address
* space.
*/
case ldl_op:
case ldr_op:
case lwl_op:
case lwr_op:
case sdl_op:
case sdr_op:
case swl_op:
case swr_op:
case lb_op:
case lbu_op:
case sb_op:
goto sigbus;
/*
* The remaining opcodes are the ones that are really of
* interest.
*/
case spec3_op:
if (insn.dsp_format.func == lx_op) {
switch (insn.dsp_format.op) {
case lwx_op:
if (user && !access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.dsp_format.rd] = value;
break;
case lhx_op:
if (user && !access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.dsp_format.rd] = value;
break;
default:
goto sigill;
}
}
#ifdef CONFIG_EVA
else {
/*
* we can land here only from kernel accessing user
* memory, so we need to "switch" the address limit to
* user space, so that address check can work properly.
*/
switch (insn.spec3_format.func) {
case lhe_op:
if (!access_ok(addr, 2))
goto sigbus;
LoadHWE(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case lwe_op:
if (!access_ok(addr, 4))
goto sigbus;
LoadWE(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case lhue_op:
if (!access_ok(addr, 2))
goto sigbus;
LoadHWUE(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.spec3_format.rt] = value;
break;
case she_op:
if (!access_ok(addr, 2))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreHWE(addr, value, res);
if (res)
goto fault;
break;
case swe_op:
if (!access_ok(addr, 4))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreWE(addr, value, res);
if (res)
goto fault;
break;
default:
goto sigill;
}
}
#endif
break;
case lh_op:
if (user && !access_ok(addr, 2))
goto sigbus;
if (IS_ENABLED(CONFIG_EVA) && user)
LoadHWE(addr, value, res);
else
LoadHW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
case lw_op:
if (user && !access_ok(addr, 4))
goto sigbus;
if (IS_ENABLED(CONFIG_EVA) && user)
LoadWE(addr, value, res);
else
LoadW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
case lhu_op:
if (user && !access_ok(addr, 2))
goto sigbus;
if (IS_ENABLED(CONFIG_EVA) && user)
LoadHWUE(addr, value, res);
else
LoadHWU(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
case lwu_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 4))
goto sigbus;
LoadWU(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case ld_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
compute_return_epc(regs);
regs->regs[insn.i_format.rt] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case sh_op:
if (user && !access_ok(addr, 2))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];
if (IS_ENABLED(CONFIG_EVA) && user)
StoreHWE(addr, value, res);
else
StoreHW(addr, value, res);
if (res)
goto fault;
break;
case sw_op:
if (user && !access_ok(addr, 4))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];
if (IS_ENABLED(CONFIG_EVA) && user)
StoreWE(addr, value, res);
else
StoreW(addr, value, res);
if (res)
goto fault;
break;
case sd_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 8))
goto sigbus;
compute_return_epc(regs);
value = regs->regs[insn.i_format.rt];
StoreDW(addr, value, res);
if (res)
goto fault;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
#ifdef CONFIG_MIPS_FP_SUPPORT
case lwc1_op:
case ldc1_op:
case swc1_op:
case sdc1_op:
case cop1x_op: {
void __user *fault_addr = NULL;
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
&fault_addr);
own_fpu(1); /* Restore FPU state. */
/* Signal if something went wrong. */
process_fpemu_return(res, fault_addr, 0);
if (res == 0)
break;
return;
}
#endif /* CONFIG_MIPS_FP_SUPPORT */
#ifdef CONFIG_CPU_HAS_MSA
case msa_op: {
unsigned int wd, preempted;
enum msa_2b_fmt df;
union fpureg *fpr;
if (!cpu_has_msa)
goto sigill;
/*
* If we've reached this point then userland should have taken
* the MSA disabled exception & initialised vector context at
* some point in the past.
*/
BUG_ON(!thread_msa_context_live());
df = insn.msa_mi10_format.df;
wd = insn.msa_mi10_format.wd;
fpr = &current->thread.fpu.fpr[wd];
switch (insn.msa_mi10_format.func) {
case msa_ld_op:
if (!access_ok(addr, sizeof(*fpr)))
goto sigbus;
do {
/*
* If we have live MSA context keep track of
* whether we get preempted in order to avoid
* the register context we load being clobbered
* by the live context as it's saved during
* preemption. If we don't have live context
* then it can't be saved to clobber the value
* we load.
*/
preempted = test_thread_flag(TIF_USEDMSA);
res = __copy_from_user_inatomic(fpr, addr,
sizeof(*fpr));
if (res)
goto fault;
/*
* Update the hardware register if it is in use
* by the task in this quantum, in order to
* avoid having to save & restore the whole
* vector context.
*/
preempt_disable();
if (test_thread_flag(TIF_USEDMSA)) {
write_msa_wr(wd, fpr, df);
preempted = 0;
}
preempt_enable();
} while (preempted);
break;
case msa_st_op:
if (!access_ok(addr, sizeof(*fpr)))
goto sigbus;
/*
* Update from the hardware register if it is in use by
* the task in this quantum, in order to avoid having to
* save & restore the whole vector context.
*/
preempt_disable();
if (test_thread_flag(TIF_USEDMSA))
read_msa_wr(wd, fpr, df);
preempt_enable();
res = __copy_to_user_inatomic(addr, fpr, sizeof(*fpr));
if (res)
goto fault;
break;
default:
goto sigbus;
}
compute_return_epc(regs);
break;
}
#endif /* CONFIG_CPU_HAS_MSA */
#ifndef CONFIG_CPU_MIPSR6
/*
* COP2 is available to implementor for application specific use.
* It's up to applications to register a notifier chain and do
* whatever they have to do, including possible sending of signals.
*
* This instruction has been reallocated in Release 6
*/
case lwc2_op:
cu2_notifier_call_chain(CU2_LWC2_OP, regs);
break;
case ldc2_op:
cu2_notifier_call_chain(CU2_LDC2_OP, regs);
break;
case swc2_op:
cu2_notifier_call_chain(CU2_SWC2_OP, regs);
break;
case sdc2_op:
cu2_notifier_call_chain(CU2_SDC2_OP, regs);
break;
#endif
default:
/*
* Pheeee... We encountered an yet unknown instruction or
* cache coherence problem. Die sucker, die ...
*/
goto sigill;
}
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
return;
fault:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
sigill:
die_if_kernel
("Unhandled kernel unaligned access or invalid instruction", regs);
force_sig(SIGILL);
}
/* Recode table from 16-bit register notation to 32-bit GPR. */
const int reg16to32[] = { 16, 17, 2, 3, 4, 5, 6, 7 };
/* Recode table from 16-bit STORE register notation to 32-bit GPR. */
static const int reg16to32st[] = { 0, 17, 2, 3, 4, 5, 6, 7 };
static void emulate_load_store_microMIPS(struct pt_regs *regs,
void __user *addr)
{
unsigned long value;
unsigned int res;
int i;
unsigned int reg = 0, rvar;
unsigned long orig31;
u16 __user *pc16;
u16 halfword;
unsigned int word;
unsigned long origpc, contpc;
union mips_instruction insn;
struct mm_decoded_insn mminsn;
bool user = user_mode(regs);
origpc = regs->cp0_epc;
orig31 = regs->regs[31];
mminsn.micro_mips_mode = 1;
/*
* This load never faults.
*/
pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc);
__get_user(halfword, pc16);
pc16++;
contpc = regs->cp0_epc + 2;
word = ((unsigned int)halfword << 16);
mminsn.pc_inc = 2;
if (!mm_insn_16bit(halfword)) {
__get_user(halfword, pc16);
pc16++;
contpc = regs->cp0_epc + 4;
mminsn.pc_inc = 4;
word |= halfword;
}
mminsn.insn = word;
if (get_user(halfword, pc16))
goto fault;
mminsn.next_pc_inc = 2;
word = ((unsigned int)halfword << 16);
if (!mm_insn_16bit(halfword)) {
pc16++;
if (get_user(halfword, pc16))
goto fault;
mminsn.next_pc_inc = 4;
word |= halfword;
}
mminsn.next_insn = word;
insn = (union mips_instruction)(mminsn.insn);
if (mm_isBranchInstr(regs, mminsn, &contpc))
insn = (union mips_instruction)(mminsn.next_insn);
/* Parse instruction to find what to do */
switch (insn.mm_i_format.opcode) {
case mm_pool32a_op:
switch (insn.mm_x_format.func) {
case mm_lwxs_op:
reg = insn.mm_x_format.rd;
goto loadW;
}
goto sigbus;
case mm_pool32b_op:
switch (insn.mm_m_format.func) {
case mm_lwp_func:
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (user && !access_ok(addr, 8))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
addr += 4;
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[reg + 1] = value;
goto success;
case mm_swp_func:
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (user && !access_ok(addr, 8))
goto sigbus;
value = regs->regs[reg];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
value = regs->regs[reg + 1];
StoreW(addr, value, res);
if (res)
goto fault;
goto success;
case mm_ldp_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (user && !access_ok(addr, 16))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
addr += 8;
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[reg + 1] = value;
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
case mm_sdp_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
if (reg == 31)
goto sigbus;
if (user && !access_ok(addr, 16))
goto sigbus;
value = regs->regs[reg];
StoreDW(addr, value, res);
if (res)
goto fault;
addr += 8;
value = regs->regs[reg + 1];
StoreDW(addr, value, res);
if (res)
goto fault;
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
case mm_lwm32_func:
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (user && !access_ok(addr, 4 * (rvar + 1)))
goto sigbus;
} else {
if (user && !access_ok(addr, 4 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
LoadW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[i] = value;
}
if ((reg & 0xf) == 9) {
LoadW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[30] = value;
}
if (reg & 0x10) {
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[31] = value;
}
goto success;
case mm_swm32_func:
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (user && !access_ok(addr, 4 * (rvar + 1)))
goto sigbus;
} else {
if (user && !access_ok(addr, 4 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
value = regs->regs[i];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
}
if ((reg & 0xf) == 9) {
value = regs->regs[30];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
}
if (reg & 0x10) {
value = regs->regs[31];
StoreW(addr, value, res);
if (res)
goto fault;
}
goto success;
case mm_ldm_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (user && !access_ok(addr, 8 * (rvar + 1)))
goto sigbus;
} else {
if (user && !access_ok(addr, 8 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
LoadDW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[i] = value;
}
if ((reg & 0xf) == 9) {
LoadDW(addr, value, res);
if (res)
goto fault;
addr += 8;
regs->regs[30] = value;
}
if (reg & 0x10) {
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[31] = value;
}
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
case mm_sdm_func:
#ifdef CONFIG_64BIT
reg = insn.mm_m_format.rd;
rvar = reg & 0xf;
if ((rvar > 9) || !reg)
goto sigill;
if (reg & 0x10) {
if (user && !access_ok(addr, 8 * (rvar + 1)))
goto sigbus;
} else {
if (user && !access_ok(addr, 8 * rvar))
goto sigbus;
}
if (rvar == 9)
rvar = 8;
for (i = 16; rvar; rvar--, i++) {
value = regs->regs[i];
StoreDW(addr, value, res);
if (res)
goto fault;
addr += 8;
}
if ((reg & 0xf) == 9) {
value = regs->regs[30];
StoreDW(addr, value, res);
if (res)
goto fault;
addr += 8;
}
if (reg & 0x10) {
value = regs->regs[31];
StoreDW(addr, value, res);
if (res)
goto fault;
}
goto success;
#endif /* CONFIG_64BIT */
goto sigill;
/* LWC2, SWC2, LDC2, SDC2 are not serviced */
}
goto sigbus;
case mm_pool32c_op:
switch (insn.mm_m_format.func) {
case mm_lwu_func:
reg = insn.mm_m_format.rd;
goto loadWU;
}
/* LL,SC,LLD,SCD are not serviced */
goto sigbus;
#ifdef CONFIG_MIPS_FP_SUPPORT
case mm_pool32f_op:
switch (insn.mm_x_format.func) {
case mm_lwxc1_func:
case mm_swxc1_func:
case mm_ldxc1_func:
case mm_sdxc1_func:
goto fpu_emul;
}
goto sigbus;
case mm_ldc132_op:
case mm_sdc132_op:
case mm_lwc132_op:
case mm_swc132_op: {
void __user *fault_addr = NULL;
fpu_emul:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
die_if_kernel("Unaligned FP access in kernel code", regs);
BUG_ON(!used_math());
BUG_ON(!is_fpu_owner());
res = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
&fault_addr);
own_fpu(1); /* restore FPU state */
/* If something went wrong, signal */
process_fpemu_return(res, fault_addr, 0);
if (res == 0)
goto success;
return;
}
#endif /* CONFIG_MIPS_FP_SUPPORT */
case mm_lh32_op:
reg = insn.mm_i_format.rt;
goto loadHW;
case mm_lhu32_op:
reg = insn.mm_i_format.rt;
goto loadHWU;
case mm_lw32_op:
reg = insn.mm_i_format.rt;
goto loadW;
case mm_sh32_op:
reg = insn.mm_i_format.rt;
goto storeHW;
case mm_sw32_op:
reg = insn.mm_i_format.rt;
goto storeW;
case mm_ld32_op:
reg = insn.mm_i_format.rt;
goto loadDW;
case mm_sd32_op:
reg = insn.mm_i_format.rt;
goto storeDW;
case mm_pool16c_op:
switch (insn.mm16_m_format.func) {
case mm_lwm16_op:
reg = insn.mm16_m_format.rlist;
rvar = reg + 1;
if (user && !access_ok(addr, 4 * rvar))
goto sigbus;
for (i = 16; rvar; rvar--, i++) {
LoadW(addr, value, res);
if (res)
goto fault;
addr += 4;
regs->regs[i] = value;
}
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[31] = value;
goto success;
case mm_swm16_op:
reg = insn.mm16_m_format.rlist;
rvar = reg + 1;
if (user && !access_ok(addr, 4 * rvar))
goto sigbus;
for (i = 16; rvar; rvar--, i++) {
value = regs->regs[i];
StoreW(addr, value, res);
if (res)
goto fault;
addr += 4;
}
value = regs->regs[31];
StoreW(addr, value, res);
if (res)
goto fault;
goto success;
}
goto sigbus;
case mm_lhu16_op:
reg = reg16to32[insn.mm16_rb_format.rt];
goto loadHWU;
case mm_lw16_op:
reg = reg16to32[insn.mm16_rb_format.rt];
goto loadW;
case mm_sh16_op:
reg = reg16to32st[insn.mm16_rb_format.rt];
goto storeHW;
case mm_sw16_op:
reg = reg16to32st[insn.mm16_rb_format.rt];
goto storeW;
case mm_lwsp16_op:
reg = insn.mm16_r5_format.rt;
goto loadW;
case mm_swsp16_op:
reg = insn.mm16_r5_format.rt;
goto storeW;
case mm_lwgp16_op:
reg = reg16to32[insn.mm16_r3_format.rt];
goto loadW;
default:
goto sigill;
}
loadHW:
if (user && !access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
loadHWU:
if (user && !access_ok(addr, 2))
goto sigbus;
LoadHWU(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
loadW:
if (user && !access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
loadWU:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 4))
goto sigbus;
LoadWU(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
loadDW:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
regs->regs[reg] = value;
goto success;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
storeHW:
if (user && !access_ok(addr, 2))
goto sigbus;
value = regs->regs[reg];
StoreHW(addr, value, res);
if (res)
goto fault;
goto success;
storeW:
if (user && !access_ok(addr, 4))
goto sigbus;
value = regs->regs[reg];
StoreW(addr, value, res);
if (res)
goto fault;
goto success;
storeDW:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 8))
goto sigbus;
value = regs->regs[reg];
StoreDW(addr, value, res);
if (res)
goto fault;
goto success;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
success:
regs->cp0_epc = contpc; /* advance or branch */
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
return;
fault:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
sigill:
die_if_kernel
("Unhandled kernel unaligned access or invalid instruction", regs);
force_sig(SIGILL);
}
static void emulate_load_store_MIPS16e(struct pt_regs *regs, void __user * addr)
{
unsigned long value;
unsigned int res;
int reg;
unsigned long orig31;
u16 __user *pc16;
unsigned long origpc;
union mips16e_instruction mips16inst, oldinst;
unsigned int opcode;
int extended = 0;
bool user = user_mode(regs);
origpc = regs->cp0_epc;
orig31 = regs->regs[31];
pc16 = (unsigned short __user *)msk_isa16_mode(origpc);
/*
* This load never faults.
*/
__get_user(mips16inst.full, pc16);
oldinst = mips16inst;
/* skip EXTEND instruction */
if (mips16inst.ri.opcode == MIPS16e_extend_op) {
extended = 1;
pc16++;
__get_user(mips16inst.full, pc16);
} else if (delay_slot(regs)) {
/* skip jump instructions */
/* JAL/JALX are 32 bits but have OPCODE in first short int */
if (mips16inst.ri.opcode == MIPS16e_jal_op)
pc16++;
pc16++;
if (get_user(mips16inst.full, pc16))
goto sigbus;
}
opcode = mips16inst.ri.opcode;
switch (opcode) {
case MIPS16e_i64_op: /* I64 or RI64 instruction */
switch (mips16inst.i64.func) { /* I64/RI64 func field check */
case MIPS16e_ldpc_func:
case MIPS16e_ldsp_func:
reg = reg16to32[mips16inst.ri64.ry];
goto loadDW;
case MIPS16e_sdsp_func:
reg = reg16to32[mips16inst.ri64.ry];
goto writeDW;
case MIPS16e_sdrasp_func:
reg = 29; /* GPRSP */
goto writeDW;
}
goto sigbus;
case MIPS16e_swsp_op:
reg = reg16to32[mips16inst.ri.rx];
if (extended && cpu_has_mips16e2)
switch (mips16inst.ri.imm >> 5) {
case 0: /* SWSP */
case 1: /* SWGP */
break;
case 2: /* SHGP */
opcode = MIPS16e_sh_op;
break;
default:
goto sigbus;
}
break;
case MIPS16e_lwpc_op:
reg = reg16to32[mips16inst.ri.rx];
break;
case MIPS16e_lwsp_op:
reg = reg16to32[mips16inst.ri.rx];
if (extended && cpu_has_mips16e2)
switch (mips16inst.ri.imm >> 5) {
case 0: /* LWSP */
case 1: /* LWGP */
break;
case 2: /* LHGP */
opcode = MIPS16e_lh_op;
break;
case 4: /* LHUGP */
opcode = MIPS16e_lhu_op;
break;
default:
goto sigbus;
}
break;
case MIPS16e_i8_op:
if (mips16inst.i8.func != MIPS16e_swrasp_func)
goto sigbus;
reg = 29; /* GPRSP */
break;
default:
reg = reg16to32[mips16inst.rri.ry];
break;
}
switch (opcode) {
case MIPS16e_lb_op:
case MIPS16e_lbu_op:
case MIPS16e_sb_op:
goto sigbus;
case MIPS16e_lh_op:
if (user && !access_ok(addr, 2))
goto sigbus;
LoadHW(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
case MIPS16e_lhu_op:
if (user && !access_ok(addr, 2))
goto sigbus;
LoadHWU(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
case MIPS16e_lw_op:
case MIPS16e_lwpc_op:
case MIPS16e_lwsp_op:
if (user && !access_ok(addr, 4))
goto sigbus;
LoadW(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
case MIPS16e_lwu_op:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 4))
goto sigbus;
LoadWU(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case MIPS16e_ld_op:
loadDW:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 8))
goto sigbus;
LoadDW(addr, value, res);
if (res)
goto fault;
MIPS16e_compute_return_epc(regs, &oldinst);
regs->regs[reg] = value;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
case MIPS16e_sh_op:
if (user && !access_ok(addr, 2))
goto sigbus;
MIPS16e_compute_return_epc(regs, &oldinst);
value = regs->regs[reg];
StoreHW(addr, value, res);
if (res)
goto fault;
break;
case MIPS16e_sw_op:
case MIPS16e_swsp_op:
case MIPS16e_i8_op: /* actually - MIPS16e_swrasp_func */
if (user && !access_ok(addr, 4))
goto sigbus;
MIPS16e_compute_return_epc(regs, &oldinst);
value = regs->regs[reg];
StoreW(addr, value, res);
if (res)
goto fault;
break;
case MIPS16e_sd_op:
writeDW:
#ifdef CONFIG_64BIT
/*
* A 32-bit kernel might be running on a 64-bit processor. But
* if we're on a 32-bit processor and an i-cache incoherency
* or race makes us see a 64-bit instruction here the sdl/sdr
* would blow up, so for now we don't handle unaligned 64-bit
* instructions on 32-bit kernels.
*/
if (user && !access_ok(addr, 8))
goto sigbus;
MIPS16e_compute_return_epc(regs, &oldinst);
value = regs->regs[reg];
StoreDW(addr, value, res);
if (res)
goto fault;
break;
#endif /* CONFIG_64BIT */
/* Cannot handle 64-bit instructions in 32-bit kernel */
goto sigill;
default:
/*
* Pheeee... We encountered an yet unknown instruction or
* cache coherence problem. Die sucker, die ...
*/
goto sigill;
}
#ifdef CONFIG_DEBUG_FS
unaligned_instructions++;
#endif
return;
fault:
/* roll back jump/branch */
regs->cp0_epc = origpc;
regs->regs[31] = orig31;
/* Did we have an exception handler installed? */
if (fixup_exception(regs))
return;
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGSEGV);
return;
sigbus:
die_if_kernel("Unhandled kernel unaligned access", regs);
force_sig(SIGBUS);
return;
sigill:
die_if_kernel
("Unhandled kernel unaligned access or invalid instruction", regs);
force_sig(SIGILL);
}
asmlinkage void do_ade(struct pt_regs *regs)
{
enum ctx_state prev_state;
unsigned int *pc;
prev_state = exception_enter();
perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS,
1, regs, regs->cp0_badvaddr);
/*
* Did we catch a fault trying to load an instruction?
*/
if (regs->cp0_badvaddr == regs->cp0_epc)
goto sigbus;
if (user_mode(regs) && !test_thread_flag(TIF_FIXADE))
goto sigbus;
if (unaligned_action == UNALIGNED_ACTION_SIGNAL)
goto sigbus;
/*
* Do branch emulation only if we didn't forward the exception.
* This is all so but ugly ...
*/
/*
* Are we running in microMIPS mode?
*/
if (get_isa16_mode(regs->cp0_epc)) {
/*
* Did we catch a fault trying to load an instruction in
* 16-bit mode?
*/
if (regs->cp0_badvaddr == msk_isa16_mode(regs->cp0_epc))
goto sigbus;
if (unaligned_action == UNALIGNED_ACTION_SHOW)
show_registers(regs);
if (cpu_has_mmips) {
emulate_load_store_microMIPS(regs,
(void __user *)regs->cp0_badvaddr);
return;
}
if (cpu_has_mips16) {
emulate_load_store_MIPS16e(regs,
(void __user *)regs->cp0_badvaddr);
return;
}
goto sigbus;
}
if (unaligned_action == UNALIGNED_ACTION_SHOW)
show_registers(regs);
pc = (unsigned int *)exception_epc(regs);
emulate_load_store_insn(regs, (void __user *)regs->cp0_badvaddr, pc);
return;
sigbus:
die_if_kernel("Kernel unaligned instruction access", regs);
force_sig(SIGBUS);
/*
* XXX On return from the signal handler we should advance the epc
*/
exception_exit(prev_state);
}
#ifdef CONFIG_DEBUG_FS
static int __init debugfs_unaligned(void)
{
debugfs_create_u32("unaligned_instructions", S_IRUGO, mips_debugfs_dir,
&unaligned_instructions);
debugfs_create_u32("unaligned_action", S_IRUGO | S_IWUSR,
mips_debugfs_dir, &unaligned_action);
return 0;
}
arch_initcall(debugfs_unaligned);
#endif
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