On 2017/06/06 02:29PM, Balbir Singh wrote:
> With text moving to read-only migrate optprobes to using
> the patch_instruction infrastructure. Without this optprobes
> will fail and complain.
>
> Signed-off-by: Balbir Singh <bsinghar...@gmail.com>
> ---
> arch/powerpc/kernel/optprobes.c | 58
> ++++++++++++++++++++++++++---------------
> 1 file changed, 37 insertions(+), 21 deletions(-)
>
> diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
> index ec60ed0..1c7326c 100644
> --- a/arch/powerpc/kernel/optprobes.c
> +++ b/arch/powerpc/kernel/optprobes.c
> @@ -158,12 +158,13 @@ void arch_remove_optimized_kprobe(struct
> optimized_kprobe *op)
> void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr)
> {
> /* addis r4,0,(insn)@h */
> - *addr++ = PPC_INST_ADDIS | ___PPC_RT(4) |
> - ((val >> 16) & 0xffff);
> + patch_instruction((unsigned int *)addr, PPC_INST_ADDIS | ___PPC_RT(4) |
We can probably get rid of those casts, seeing as we're not using it in
kprobes.c.
> + ((val >> 16) & 0xffff));
> + addr++;
>
> /* ori r4,r4,(insn)@l */
> - *addr = PPC_INST_ORI | ___PPC_RA(4) | ___PPC_RS(4) |
> - (val & 0xffff);
> + patch_instruction((unsigned int *)addr, PPC_INST_ORI | ___PPC_RA(4) |
> + ___PPC_RS(4) | (val & 0xffff));
> }
>
> /*
> @@ -173,24 +174,28 @@ void patch_imm32_load_insns(unsigned int val,
> kprobe_opcode_t *addr)
> void patch_imm64_load_insns(unsigned long val, kprobe_opcode_t *addr)
> {
> /* lis r3,(op)@highest */
> - *addr++ = PPC_INST_ADDIS | ___PPC_RT(3) |
> - ((val >> 48) & 0xffff);
> + patch_instruction((unsigned int *)addr, PPC_INST_ADDIS | ___PPC_RT(3) |
> + ((val >> 48) & 0xffff));
> + addr++;
>
> /* ori r3,r3,(op)@higher */
> - *addr++ = PPC_INST_ORI | ___PPC_RA(3) | ___PPC_RS(3) |
> - ((val >> 32) & 0xffff);
> + patch_instruction((unsigned int *)addr, PPC_INST_ORI | ___PPC_RA(3) |
> + ___PPC_RS(3) | ((val >> 32) & 0xffff));
> + addr++;
>
> /* rldicr r3,r3,32,31 */
> - *addr++ = PPC_INST_RLDICR | ___PPC_RA(3) | ___PPC_RS(3) |
> - __PPC_SH64(32) | __PPC_ME64(31);
> + patch_instruction((unsigned int *)addr, PPC_INST_RLDICR | ___PPC_RA(3) |
> + ___PPC_RS(3) | __PPC_SH64(32) | __PPC_ME64(31));
> + addr++;
>
> /* oris r3,r3,(op)@h */
> - *addr++ = PPC_INST_ORIS | ___PPC_RA(3) | ___PPC_RS(3) |
> - ((val >> 16) & 0xffff);
> + patch_instruction((unsigned int *)addr, PPC_INST_ORIS | ___PPC_RA(3) |
> + ___PPC_RS(3) | ((val >> 16) & 0xffff));
> + addr++;
>
> /* ori r3,r3,(op)@l */
> - *addr = PPC_INST_ORI | ___PPC_RA(3) | ___PPC_RS(3) |
> - (val & 0xffff);
> + patch_instruction((unsigned int *)addr, PPC_INST_ORI | ___PPC_RA(3) |
> + ___PPC_RS(3) | (val & 0xffff));
> }
>
> int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe
> *p)
> @@ -198,7 +203,8 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe
> *op, struct kprobe *p)
> kprobe_opcode_t *buff, branch_op_callback, branch_emulate_step;
> kprobe_opcode_t *op_callback_addr, *emulate_step_addr;
> long b_offset;
> - unsigned long nip;
> + unsigned long nip, size;
> + int rc, i;
>
> kprobe_ppc_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
>
> @@ -231,8 +237,15 @@ int arch_prepare_optimized_kprobe(struct
> optimized_kprobe *op, struct kprobe *p)
> goto error;
>
> /* Setup template */
> - memcpy(buff, optprobe_template_entry,
> - TMPL_END_IDX * sizeof(kprobe_opcode_t));
> + /* We can optimize this via patch_instruction_window later */
This probably needs a TODO just so it's clear. I do think this would be
good to add since we copy many instructions while setting up the
optprobe, so this is quite slow as it exists today.
> + size = (TMPL_END_IDX * sizeof(kprobe_opcode_t)) / sizeof(int);
That's just TMPL_END_IDX.
Thanks,
Naveen
> + pr_devel("Copying template to %p, size %lu\n", buff, size);
> + for (i = 0; i < size; i++) {
> + rc = patch_instruction((unsigned int *)buff + i,
> + *((unsigned int *)(optprobe_template_entry) + i));
> + if (rc < 0)
> + goto error;
> + }
>
> /*
> * Fixup the template with instructions to:
> @@ -261,8 +274,10 @@ int arch_prepare_optimized_kprobe(struct
> optimized_kprobe *op, struct kprobe *p)
> if (!branch_op_callback || !branch_emulate_step)
> goto error;
>
> - buff[TMPL_CALL_HDLR_IDX] = branch_op_callback;
> - buff[TMPL_EMULATE_IDX] = branch_emulate_step;
> + patch_instruction((unsigned int *)buff + TMPL_CALL_HDLR_IDX,
> + branch_op_callback);
> + patch_instruction((unsigned int *)buff + TMPL_EMULATE_IDX,
> + branch_emulate_step);
>
> /*
> * 3. load instruction to be emulated into relevant register, and
> @@ -272,8 +287,9 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe
> *op, struct kprobe *p)
> /*
> * 4. branch back from trampoline
> */
> - buff[TMPL_RET_IDX] = create_branch((unsigned int *)buff + TMPL_RET_IDX,
> - (unsigned long)nip, 0);
> + patch_instruction((unsigned int *)buff + TMPL_RET_IDX,
> + create_branch((unsigned int *)buff +
> + TMPL_RET_IDX, (unsigned long)nip, 0));
>
> flush_icache_range((unsigned long)buff,
> (unsigned long)(&buff[TMPL_END_IDX]));
> --
> 2.9.4
>
