From eba1f853edf794ec259ec7b5e5a6efee5ede989f Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Wed, 1 May 2024 23:00:09 -0700 Subject: perf annotate-data: Check memory access with two registers 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 Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240502060011.1838090-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/annotate-data.c | 44 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 39 insertions(+), 5 deletions(-) (limited to 'tools') diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index f1e52a531563..245e3ef3e2ff 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -1031,22 +1031,37 @@ retry: 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 @@ again: 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; -- cgit