From patchwork Tue Mar 19 05:51:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13596146 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1620B7FBAF; Tue, 19 Mar 2024 05:51:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710827488; cv=none; b=tGuQ7JLrjw+XUkwQg6kG/WFaPnbo3T/hy40h07Fzy7WMOxsVxmubh6OCjqHF6+0beQcfuKMD7CAMfo9GLdedtbUgkNgDig2AmQHQM7ELDm622E7U+ykKsMHuf+gnKBe6N3kfyoQUh0f7gUGbXbe9aBxs2NAR92iJNkiBEqyzy3o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710827488; c=relaxed/simple; bh=uJSdghEGLKMsHLGxhc9BRL8wS6WYTQdxoEBPQ8UAYQ0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GoHNcoF+GmZjO9h3Iiii7PgUqe3fWH3gykKzeZVTCFHHgFsMgG3oA6u5gB8K9BXCPHRfmFrk/Txzk4gnTgACe/BYT5qI8Ke6CqgU0PaYC+lzzgUgonF3aSVhEP9IemxYTeekYC8WuDjuYSePOWVj0qOdwzxrHrITa3KRgLlupio= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hInb/Drm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hInb/Drm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74F2AC43390; Tue, 19 Mar 2024 05:51:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710827487; bh=uJSdghEGLKMsHLGxhc9BRL8wS6WYTQdxoEBPQ8UAYQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hInb/DrmioxpC/1b7/UzJjjH3S6SZXRm5+NvXmMkdpP7JdiNPwPzW/CgECrt99GvY WmuldXyzJMwtk40n/QQ2ONF2418mBqW7Zw0e7oLN0rkSB254XqIlWXDm0ABEP/OKU1 6NV/YUeVNRoYlNJSYqtTMkii+8SKg338p+T2k8KZgm55W56DJdGSIfI92ByX2KowqZ M2m4bASKV0mDFFcA8HjVusbUrJ3e+Il9HH66nCq+yr0DerAksUJyT/N/NBzQqyiD6Q Jfye6q9ShAs8WdQZVBPQswKw1RpDun2pud2Maco9073Hvo9oQSfnUCZuhVWlqeExX6 7zVJjx58hK0FA== From: Namhyung Kim To: Arnaldo Carvalho de Melo , Ian Rogers Cc: Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Linus Torvalds , Stephane Eranian , Masami Hiramatsu , linux-toolchains@vger.kernel.org, linux-trace-devel@vger.kernel.org Subject: [PATCH 17/23] perf annotate-data: Handle this-cpu variables in kernel Date: Mon, 18 Mar 2024 22:51:09 -0700 Message-ID: <20240319055115.4063940-18-namhyung@kernel.org> X-Mailer: git-send-email 2.44.0.291.gc1ea87d7ee-goog In-Reply-To: <20240319055115.4063940-1-namhyung@kernel.org> References: <20240319055115.4063940-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On x86, the kernel gets the current task using the current macro like below: #define current get_current() static __always_inline struct task_struct *get_current(void) { return this_cpu_read_stable(pcpu_hot.current_task); } So it returns the current_task field of struct pcpu_hot which is the first member. On my build, it's located at 0x32940. $ nm vmlinux | grep pcpu_hot 0000000000032940 D pcpu_hot And the current macro generates the instructions like below: mov %gs:0x32940, %rcx So the %gs segment register points to the beginning of the per-cpu region of this cpu and it points the variable with a constant. Let's update the instruction location info to have a segment register and handle %gs in kernel to look up a global variable. Pretend it as a global variable by changing the register number to DWARF_REG_PC. Signed-off-by: Namhyung Kim --- tools/perf/util/annotate-data.c | 21 +++++++++++++++++++-- tools/perf/util/annotate.c | 7 +++++++ 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index f5329a78a97d..d57622ddd5d3 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -790,7 +790,7 @@ static void delete_var_types(struct die_var_type *var_types) /* It's at the target address, check if it has a matching type */ static bool check_matching_type(struct type_state *state, struct data_loc_info *dloc, int reg, - Dwarf_Die *type_die) + Dwarf_Die *cu_die, Dwarf_Die *type_die) { Dwarf_Word size; u32 insn_offset = dloc->ip - dloc->ms->sym->start; @@ -864,6 +864,23 @@ static bool check_matching_type(struct type_state *state, return true; } + if (map__dso(dloc->ms->map)->kernel && arch__is(dloc->arch, "x86")) { + u64 addr; + int offset; + + if (dloc->op->segment == INSN_SEG_X86_GS && dloc->op->imm) { + pr_debug_dtp(" this-cpu var\n"); + + addr = dloc->op->offset; + + if (get_global_var_type(cu_die, dloc, dloc->ip, addr, + &offset, type_die)) { + dloc->type_offset = offset; + return true; + } + } + } + pr_debug_dtp("\n"); return false; } @@ -897,7 +914,7 @@ static bool find_data_type_insn(struct data_loc_info *dloc, int reg, if (this_ip == dloc->ip) { found = check_matching_type(&state, dloc, reg, - type_die); + cu_die, type_die); goto out; } diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c index 3aa3a3b987ad..e4121acb4f88 100644 --- a/tools/perf/util/annotate.c +++ b/tools/perf/util/annotate.c @@ -3921,6 +3921,13 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he) op_loc->offset, dl); } + /* This CPU access in kernel - pretend PC-relative addressing */ + if (map__dso(ms->map)->kernel && arch__is(arch, "x86") && + op_loc->segment == INSN_SEG_X86_GS && op_loc->imm) { + dloc.var_addr = op_loc->offset; + op_loc->reg1 = DWARF_REG_PC; + } + mem_type = find_data_type(&dloc); if (mem_type) istat->good++;