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perf annotate-data: Check memory access with two registers

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The following instruction pattern is used to access a global variable.

  mov     $0x231c0, %rax
  movsql  %edi, %rcx
  mov     -0x7dc94ae0(,%rcx,8), %rcx
  cmpl    $0x0, 0xa60(%rcx,%rax,1)     <<<--- here

The first instruction set the address of the per-cpu variable (here, it
is 'runqueues' of type 'struct rq').  The second instruction seems like
a cpu number of the per-cpu base.  The third instruction get the base
offset of per-cpu area for that cpu.  The last instruction compares the
value of the per-cpu variable at the offset of 0xa60.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240502060011.1838090-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2024-05-01 23:00:09 -07:00 committed by Arnaldo Carvalho de Melo
parent 4449c9047d
commit eba1f853ed
1 changed files with 39 additions and 5 deletions
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44
tools/perf/util/annotate-data.c
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@ -1031,22 +1031,37 @@ static void update_insn_state_x86(struct type_state *state,
else if (has_reg_type(state, sreg) &&
state->regs[sreg].kind == TSR_KIND_PERCPU_BASE) {
u64 ip = dloc->ms->sym->start + dl->al.offset;
u64 var_addr = src->offset;
int offset;
if (src->multi_regs) {
int reg2 = (sreg == src->reg1) ? src->reg2 : src->reg1;
if (has_reg_type(state, reg2) && state->regs[reg2].ok &&
state->regs[reg2].kind == TSR_KIND_CONST)
var_addr += state->regs[reg2].imm_value;
}
/*
* In kernel, %gs points to a per-cpu region for the
* current CPU. Access with a constant offset should
* be treated as a global variable access.
*/
if (get_global_var_type(cu_die, dloc, ip, src->offset,
if (get_global_var_type(cu_die, dloc, ip, var_addr,
&offset, &type_die) &&
die_get_member_type(&type_die, offset, &type_die)) {
tsr->type = type_die;
tsr->kind = TSR_KIND_TYPE;
tsr->ok = true;
pr_debug_dtp("mov [%x] percpu %#x(reg%d) -> reg%d",
insn_offset, src->offset, sreg, dst->reg1);
if (src->multi_regs) {
pr_debug_dtp("mov [%x] percpu %#x(reg%d,reg%d) -> reg%d",
insn_offset, src->offset, src->reg1,
src->reg2, dst->reg1);
} else {
pr_debug_dtp("mov [%x] percpu %#x(reg%d) -> reg%d",
insn_offset, src->offset, sreg, dst->reg1);
}
pr_debug_type_name(&tsr->type, tsr->kind);
} else {
tsr->ok = false;
@ -1340,6 +1355,17 @@ static int check_matching_type(struct type_state *state,
pr_debug_dtp(" percpu var\n");
if (dloc->op->multi_regs) {
int reg2 = dloc->op->reg2;
if (dloc->op->reg2 == reg)
reg2 = dloc->op->reg1;
if (has_reg_type(state, reg2) && state->regs[reg2].ok &&
state->regs[reg2].kind == TSR_KIND_CONST)
var_addr += state->regs[reg2].imm_value;
}
if (get_global_var_type(cu_die, dloc, dloc->ip, var_addr,
&var_offset, type_die)) {
dloc->type_offset = var_offset;
@ -1527,8 +1553,16 @@ static int find_data_type_block(struct data_loc_info *dloc, int reg,
found = find_data_type_insn(dloc, reg, &basic_blocks, var_types,
cu_die, type_die);
if (found > 0) {
pr_debug_dtp("found by insn track: %#x(reg%d) type-offset=%#x\n",
dloc->op->offset, reg, dloc->type_offset);
char buf[64];
if (dloc->op->multi_regs)
snprintf(buf, sizeof(buf), "reg%d, reg%d",
dloc->op->reg1, dloc->op->reg2);
else
snprintf(buf, sizeof(buf), "reg%d", dloc->op->reg1);
pr_debug_dtp("found by insn track: %#x(%s) type-offset=%#x\n",
dloc->op->offset, buf, dloc->type_offset);
pr_debug_type_name(type_die, TSR_KIND_TYPE);
ret = 0;
break;