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powerpc: Enable OPTPROBES on PPC32 

For that, create a 32 bits version of patch_imm64_load_insns()
and create a patch_imm_load_insns() which calls
patch_imm32_load_insns() on PPC32 and patch_imm64_load_insns()
on PPC64.

Adapt optprobes_head.S for PPC32. Use PPC_LL/PPC_STL macros instead
of raw ld/std, opt out things linked to paca and use stmw/lmw to
save/restore registers.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bad58c66859b2a475c0ad516b53164ae3b4853cd.1618927318.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-04-20 14:02:07 +00:00 committed by Michael Ellerman
parent 693557ebf4
commit eacf4c0202
3 changed files with 56 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/Kconfig
View File

@ -229,7 +229,7 @@ config PPC
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
select HAVE_HARDLOCKUP_DETECTOR_ARCH if PPC64 && PPC_BOOK3S && SMP
select HAVE_OPTPROBES if PPC64
select HAVE_OPTPROBES
select HAVE_PERF_EVENTS
select HAVE_PERF_EVENTS_NMI if PPC64
select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH

24
arch/powerpc/kernel/optprobes.c
View File

@ -141,11 +141,21 @@ void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
}
}
static void patch_imm32_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)
{
patch_instruction((struct ppc_inst *)addr,
ppc_inst(PPC_RAW_LIS(reg, IMM_H(val))));
addr++;
patch_instruction((struct ppc_inst *)addr,
ppc_inst(PPC_RAW_ORI(reg, reg, IMM_L(val))));
}
/*
* Generate instructions to load provided immediate 64-bit value
* to register 'reg' and patch these instructions at 'addr'.
*/
static void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)
static void patch_imm64_load_insns(unsigned long long val, int reg, kprobe_opcode_t *addr)
{
/* lis reg,(op)@highest */
patch_instruction((struct ppc_inst *)addr,
@ -177,6 +187,14 @@ static void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t *
___PPC_RS(reg) | (val & 0xffff)));
}
static void patch_imm_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)
{
if (IS_ENABLED(CONFIG_PPC64))
patch_imm64_load_insns(val, reg, addr);
else
patch_imm32_load_insns(val, reg, addr);
}
int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
{
struct ppc_inst branch_op_callback, branch_emulate_step, temp;
@ -230,7 +248,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
* Fixup the template with instructions to:
* 1. load the address of the actual probepoint
*/
patch_imm64_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);
patch_imm_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);
/*
* 2. branch to optimized_callback() and emulate_step()
@ -264,7 +282,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
* 3. load instruction to be emulated into relevant register, and
*/
temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
patch_imm64_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);
patch_imm_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);
/*
* 4. branch back from trampoline

65
arch/powerpc/kernel/optprobes_head.S
View File

@ -9,6 +9,16 @@
#include <asm/ptrace.h>
#include <asm/asm-offsets.h>
#ifdef CONFIG_PPC64
#define SAVE_30GPRS(base) SAVE_10GPRS(2,base); SAVE_10GPRS(12,base); SAVE_10GPRS(22,base)
#define REST_30GPRS(base) REST_10GPRS(2,base); REST_10GPRS(12,base); REST_10GPRS(22,base)
#define TEMPLATE_FOR_IMM_LOAD_INSNS nop; nop; nop; nop; nop
#else
#define SAVE_30GPRS(base) stmw r2, GPR2(base)
#define REST_30GPRS(base) lmw r2, GPR2(base)
#define TEMPLATE_FOR_IMM_LOAD_INSNS nop; nop; nop
#endif
#define OPT_SLOT_SIZE 65536
.balign 4
@ -30,39 +40,41 @@ optinsn_slot:
.global optprobe_template_entry
optprobe_template_entry:
/* Create an in-memory pt_regs */
stdu r1,-INT_FRAME_SIZE(r1)
PPC_STLU r1,-INT_FRAME_SIZE(r1)
SAVE_GPR(0,r1)
/* Save the previous SP into stack */
addi r0,r1,INT_FRAME_SIZE
std r0,GPR1(r1)
SAVE_10GPRS(2,r1)
SAVE_10GPRS(12,r1)
SAVE_10GPRS(22,r1)
PPC_STL r0,GPR1(r1)
SAVE_30GPRS(r1)
/* Save SPRS */
mfmsr r5
std r5,_MSR(r1)
PPC_STL r5,_MSR(r1)
li r5,0x700
std r5,_TRAP(r1)
PPC_STL r5,_TRAP(r1)
li r5,0
std r5,ORIG_GPR3(r1)
std r5,RESULT(r1)
PPC_STL r5,ORIG_GPR3(r1)
PPC_STL r5,RESULT(r1)
mfctr r5
std r5,_CTR(r1)
PPC_STL r5,_CTR(r1)
mflr r5
std r5,_LINK(r1)
PPC_STL r5,_LINK(r1)
mfspr r5,SPRN_XER
std r5,_XER(r1)
PPC_STL r5,_XER(r1)
mfcr r5
std r5,_CCR(r1)
PPC_STL r5,_CCR(r1)
#ifdef CONFIG_PPC64
lbz r5,PACAIRQSOFTMASK(r13)
std r5,SOFTE(r1)
#endif
/*
* We may get here from a module, so load the kernel TOC in r2.
* The original TOC gets restored when pt_regs is restored
* further below.
*/
#ifdef CONFIG_PPC64
ld r2,PACATOC(r13)
#endif
.global optprobe_template_op_address
optprobe_template_op_address:
@ -70,11 +82,8 @@ optprobe_template_op_address:
* Parameters to optimized_callback():
* 1. optimized_kprobe structure in r3
*/
nop
nop
nop
nop
nop
TEMPLATE_FOR_IMM_LOAD_INSNS
/* 2. pt_regs pointer in r4 */
addi r4,r1,STACK_FRAME_OVERHEAD
@ -92,11 +101,7 @@ optprobe_template_call_handler:
.global optprobe_template_insn
optprobe_template_insn:
/* 2, Pass instruction to be emulated in r4 */
nop
nop
nop
nop
nop
TEMPLATE_FOR_IMM_LOAD_INSNS
.global optprobe_template_call_emulate
optprobe_template_call_emulate:
@ -107,20 +112,18 @@ optprobe_template_call_emulate:
* All done.
* Now, restore the registers...
*/
ld r5,_MSR(r1)
PPC_LL r5,_MSR(r1)
mtmsr r5
ld r5,_CTR(r1)
PPC_LL r5,_CTR(r1)
mtctr r5
ld r5,_LINK(r1)
PPC_LL r5,_LINK(r1)
mtlr r5
ld r5,_XER(r1)
PPC_LL r5,_XER(r1)
mtxer r5
ld r5,_CCR(r1)
PPC_LL r5,_CCR(r1)
mtcr r5
REST_GPR(0,r1)
REST_10GPRS(2,r1)
REST_10GPRS(12,r1)
REST_10GPRS(22,r1)
REST_30GPRS(r1)
/* Restore the previous SP */
addi r1,r1,INT_FRAME_SIZE