From 4449c9047dc6f9f68333a720958cd7b58225910d Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Wed, 1 May 2024 23:00:08 -0700 Subject: [PATCH] perf annotate-data: Handle direct global variable access 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 Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240502060011.1838090-4-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/annotate-data.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index 4dd0911904f21..f1e52a531563a 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -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; -- 2.30.2