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perf annotate-arm64: Support 'mov' instruction tracking

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Extend update_insn_state_arm64() to support register-to-register and
immediate-to-register 'mov' instructions.

For register-to-register 'mov' (e.g., mov dreg, sreg), propagate data type
information from the source register to the destination register.

For immediate-to-register 'mov' (e.g., mov dreg, #imm), store the immediate
value in the destination register's imm_value field and set its kind to
TSR_KIND_CONST, allowing subsequent instructions to resolve it as a
constant.

A real-world example is shown below:

  ffff8000803eebf8 <get_vma_policy>:
  ffff8000803eec20:  mov  x21, x0          // x0 (struct vm_area_struct*) -> x21
  ffff8000803eec28:  ldr  x2, [x0, #112]
  ffff8000803eec2c:  cbz  x2, ffff8000803eec94 <get_vma_policy+0x9c>
* ffff8000803eec94:  ldr  x0, [x21, #152]

Before this commit, the type of x21 was unknown, causing the subsequent
inference to fail:

  var [0] reg0 offset 0 type='struct vm_area_struct*' size=0x8
  chk [9c] reg21 offset=0x98 ok=0 kind=0 cfa : no type information
  final result: no type information

After this commit, the type of x21 is correctly inferred as 'vm_area_struct':

  var [0] reg0 offset 0 type='struct vm_area_struct*' size=0x8
  mov [28] reg0 -> reg21 type='struct vm_area_struct*' size=0x8
  chk [9c] reg21 offset=0x98 ok=1 kind=1 (struct vm_area_struct*) : Good!
  found by insn track: 0x98(reg21) type-offset=0x98
  final result:  type='struct vm_area_struct' size=0xb0

Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Tengda Wu 2026-10-20 13:45:07 +00:00 committed by Arnaldo Carvalho de Melo
parent 861ecd5c6c
commit cf66ee3a5d
1 changed files with 53 additions and 0 deletions
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53
tools/perf/util/annotate-arch/annotate-arm64.c
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@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <errno.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include <linux/ctype.h>
@ -696,6 +697,7 @@ static int propagate_load_reg_state(struct type_state *state,
tsr->type = type_die;
tsr->kind = TSR_KIND_TYPE;
tsr->offset = 0;
tsr->imm_value = 0;
tsr->ok = true;
pr_debug_dtp("%s [%x] %#x(reg%d) -> reg%d",
@ -909,6 +911,54 @@ static void update_store_insn_state(struct type_state *state,
adjust_reg_index_state(state, dloc, dl, dst);
}
static void update_mov_insn_state(struct type_state *state,
struct disasm_line *dl,
struct annotated_op_loc *src,
struct annotated_op_loc *dst)
{
struct type_state_reg *tsr;
u32 insn_offset = dl->al.offset;
int sreg = src->reg1;
int dreg = dst->reg1;
if (!has_reg_type(state, dreg))
return;
tsr = &state->regs[dreg];
tsr->copied_from = -1;
if (src->imm) {
invalidate_reg_state(tsr);
tsr->kind = TSR_KIND_CONST;
tsr->imm_value = (s64)src->offset;
tsr->offset = 0;
tsr->ok = true;
pr_debug_dtp("mov [%x] imm=%#"PRIx64" -> reg%d\n",
insn_offset, tsr->imm_value, dreg);
return;
}
if (!has_reg_type(state, sreg) || !state->regs[sreg].ok) {
invalidate_reg_state(tsr);
return;
}
tsr->type = state->regs[sreg].type;
tsr->kind = state->regs[sreg].kind;
tsr->imm_value = state->regs[sreg].imm_value;
tsr->offset = state->regs[sreg].offset;
tsr->lifetime_active = state->regs[sreg].lifetime_active;
tsr->lifetime_end = state->regs[sreg].lifetime_end;
tsr->ok = state->regs[sreg].ok;
if (tsr->kind == TSR_KIND_TYPE || tsr->kind == TSR_KIND_POINTER)
tsr->copied_from = sreg;
pr_debug_dtp("mov [%x] reg%d -> reg%d", insn_offset, sreg, dreg);
pr_debug_type_name(&tsr->type, tsr->kind);
}
static void update_insn_state_arm64(struct type_state *state,
struct data_loc_info *dloc, Dwarf_Die *cu_die,
struct disasm_line *dl)
@ -925,6 +975,9 @@ static void update_insn_state_arm64(struct type_state *state,
if (ins__is_call(&dl->ins))
update_call_insn_state(state, dloc, cu_die, dl);
/* Register to register or imm value to register transfers */
else if (!strcmp(dl->ins.name, "mov"))
update_mov_insn_state(state, dl, src, dst);
/* Memory to register transfers */
else if (is_standard_load_insn(dl->ins.name))
update_load_insn_state(state, dloc, dl, src, dst);