Re: [PATCH V2 7/9] tools/perf: Update instruction tracking with add instruction

From: Christophe Leroy
Date: Tue May 07 2024 - 05:59:44 EST




Le 06/05/2024 à 14:19, Athira Rajeev a écrit :
> Update instruction tracking with add instruction. Apart from "mr"
> instruction, the register state is carried on by other insns, ie,
> "add, addi, addis". Since these are not memory instructions and doesn't
> fall in the range of (32 to 63), add these as part of nmemonic table.
> For now, add* instructions are added. There is possibility of getting
> more added here. But to extract regs, still the binary code will be
> used. So associate this with "load_store_ops" itself and no other
> changes required.

Looks fragile.

How do you handle addc, adde, addic ?
And also addme, addze, which only have two operands instead of 3 ?

>
> Signed-off-by: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
> ---
> .../perf/arch/powerpc/annotate/instructions.c | 21 +++++++++++++++++++
> tools/perf/util/disasm.c | 1 +
> 2 files changed, 22 insertions(+)
>
> diff --git a/tools/perf/arch/powerpc/annotate/instructions.c b/tools/perf/arch/powerpc/annotate/instructions.c
> index cce7023951fe..1f35d8a65bb4 100644
> --- a/tools/perf/arch/powerpc/annotate/instructions.c
> +++ b/tools/perf/arch/powerpc/annotate/instructions.c
> @@ -1,6 +1,17 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <linux/compiler.h>
>
> +/*
> + * powerpc instruction nmemonic table to associate load/store instructions with
> + * move_ops. mov_ops is used to identify add/mr to do instruction tracking.
> + */
> +static struct ins powerpc__instructions[] = {
> + { .name = "mr", .ops = &load_store_ops, },
> + { .name = "addi", .ops = &load_store_ops, },
> + { .name = "addis", .ops = &load_store_ops, },
> + { .name = "add", .ops = &load_store_ops, },
> +};
> +
> static struct ins_ops *powerpc__associate_instruction_ops(struct arch *arch, const char *name)
> {
> int i;
> @@ -75,6 +86,9 @@ static void update_insn_state_powerpc(struct type_state *state,
> if (annotate_get_insn_location(dloc->arch, dl, &loc) < 0)
> return;
>
> + if (!strncmp(dl->ins.name, "add", 3))
> + goto regs_check;
> +
> if (strncmp(dl->ins.name, "mr", 2))
> return;
>
> @@ -85,6 +99,7 @@ static void update_insn_state_powerpc(struct type_state *state,
> dst->reg1 = src_reg;
> }
>
> +regs_check:
> if (!has_reg_type(state, dst->reg1))
> return;
>
> @@ -115,6 +130,12 @@ static void update_insn_state_powerpc(struct type_state *state __maybe_unused, s
> static int powerpc__annotate_init(struct arch *arch, char *cpuid __maybe_unused)
> {
> if (!arch->initialized) {
> + arch->nr_instructions = ARRAY_SIZE(powerpc__instructions);
> + arch->instructions = calloc(arch->nr_instructions, sizeof(struct ins));
> + if (!arch->instructions)
> + return -ENOMEM;
> + memcpy(arch->instructions, powerpc__instructions, sizeof(struct ins) * arch->nr_instructions);
> + arch->nr_instructions_allocated = arch->nr_instructions;
> arch->initialized = true;
> arch->associate_instruction_ops = powerpc__associate_instruction_ops;
> arch->objdump.comment_char = '#';
> diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
> index ac6b8b8da38a..32cf506a9010 100644
> --- a/tools/perf/util/disasm.c
> +++ b/tools/perf/util/disasm.c
> @@ -36,6 +36,7 @@ static struct ins_ops mov_ops;
> static struct ins_ops nop_ops;
> static struct ins_ops lock_ops;
> static struct ins_ops ret_ops;
> +static struct ins_ops load_store_ops;
>
> static int jump__scnprintf(struct ins *ins, char *bf, size_t size,
> struct ins_operands *ops, int max_ins_name);