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perf annotate-data: Handle direct global variable access

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Like per-cpu base offset array, sometimes it accesses the global
variable directly using the offset.  Allow this type of instructions as
long as it finds a global variable for the address.

  movslq  %edi, %rcx
  mov     -0x7dc94ae0(,%rcx,8), %rcx   <<<--- here

As %rcx has a valid type (i.e. array index) from the first instruction,
it will be checked by the first case in check_matching_type().  But as
it's not a pointer type, the match will fail.  But in this case, it
should check if it accesses the kernel global array variable.

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/20240502060011.1838090-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2024-05-01 23:00:08 -07:00 committed by Arnaldo Carvalho de Melo
parent c1da8411e4
commit 4449c9047d
1 changed files with 15 additions and 12 deletions
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27
tools/perf/util/annotate-data.c
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@ -1256,14 +1256,19 @@ static int check_matching_type(struct type_state *state,
if (state->regs[reg].ok && state->regs[reg].kind == TSR_KIND_TYPE) {
int tag = dwarf_tag(&state->regs[reg].type);
pr_debug_dtp("\n");
/*
* Normal registers should hold a pointer (or array) to
* dereference a memory location.
*/
if (tag != DW_TAG_pointer_type && tag != DW_TAG_array_type)
if (tag != DW_TAG_pointer_type && tag != DW_TAG_array_type) {
if (dloc->op->offset < 0 && reg != state->stack_reg)
goto check_kernel;
pr_debug_dtp("\n");
return -1;
}
pr_debug_dtp("\n");
/* Remove the pointer and get the target type */
if (die_get_real_type(&state->regs[reg].type, type_die) == NULL)
@ -1376,12 +1381,14 @@ static int check_matching_type(struct type_state *state,
return -1;
}
if (map__dso(dloc->ms->map)->kernel && arch__is(dloc->arch, "x86")) {
check_kernel:
if (map__dso(dloc->ms->map)->kernel) {
u64 addr;
int offset;
/* Direct this-cpu access like "%gs:0x34740" */
if (dloc->op->segment == INSN_SEG_X86_GS && dloc->op->imm) {
if (dloc->op->segment == INSN_SEG_X86_GS && dloc->op->imm &&
arch__is(dloc->arch, "x86")) {
pr_debug_dtp(" this-cpu var\n");
addr = dloc->op->offset;
@ -1394,17 +1401,13 @@ static int check_matching_type(struct type_state *state,
return -1;
}
/* Access to per-cpu base like "-0x7dcf0500(,%rdx,8)" */
/* Access to global variable like "-0x7dcf0500(,%rdx,8)" */
if (dloc->op->offset < 0 && reg != state->stack_reg) {
const char *var_name = NULL;
addr = (s64) dloc->op->offset;
if (get_global_var_info(dloc, addr, &var_name, &offset) &&
!strcmp(var_name, "__per_cpu_offset") && offset == 0 &&
get_global_var_type(cu_die, dloc, dloc->ip, addr,
if (get_global_var_type(cu_die, dloc, dloc->ip, addr,
&offset, type_die)) {
pr_debug_dtp(" percpu base\n");
pr_debug_dtp(" global var\n");
dloc->type_offset = offset;
return 1;