From: Jiri Olsa <jolsa@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Song Liu <songliubraving@fb.com>,
lkml <linux-kernel@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Michael Petlan <mpetlan@redhat.com>,
Ian Rogers <irogers@google.com>,
Stephane Eranian <eranian@google.com>,
Alexey Budankov <alexey.budankov@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>,
Adrian Hunter <adrian.hunter@intel.com>
Subject: [PATCH 01/25] bpf: Move stack_map_get_build_id into lib
Date: Thu, 26 Nov 2020 18:00:02 +0100 [thread overview]
Message-ID: <20201126170026.2619053-2-jolsa@kernel.org> (raw)
In-Reply-To: <20201126170026.2619053-1-jolsa@kernel.org>
Moving stack_map_get_build_id into lib with
declaration in linux/buildid.h header:
int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id);
This function returns build id for given struct vm_area_struct.
There is no functional change to stack_map_get_build_id function.
Cc: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
include/linux/buildid.h | 11 ++++
kernel/bpf/stackmap.c | 143 ++--------------------------------------
lib/Makefile | 3 +-
lib/buildid.c | 136 ++++++++++++++++++++++++++++++++++++++
4 files changed, 153 insertions(+), 140 deletions(-)
create mode 100644 include/linux/buildid.h
create mode 100644 lib/buildid.c
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
new file mode 100644
index 000000000000..3be5b49719f1
--- /dev/null
+++ b/include/linux/buildid.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_BUILDID_H
+#define _LINUX_BUILDID_H
+
+#include <linux/mm_types.h>
+
+#define BUILD_ID_SIZE 20
+
+int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id);
+
+#endif
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 06065fa27124..7df08f8af5a1 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -7,10 +7,9 @@
#include <linux/kernel.h>
#include <linux/stacktrace.h>
#include <linux/perf_event.h>
-#include <linux/elf.h>
-#include <linux/pagemap.h>
#include <linux/irq_work.h>
#include <linux/btf_ids.h>
+#include <linux/buildid.h>
#include "percpu_freelist.h"
#define STACK_CREATE_FLAG_MASK \
@@ -153,140 +152,6 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
return ERR_PTR(err);
}
-#define BPF_BUILD_ID 3
-/*
- * Parse build id from the note segment. This logic can be shared between
- * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
- * identical.
- */
-static inline int stack_map_parse_build_id(void *page_addr,
- unsigned char *build_id,
- void *note_start,
- Elf32_Word note_size)
-{
- Elf32_Word note_offs = 0, new_offs;
-
- /* check for overflow */
- if (note_start < page_addr || note_start + note_size < note_start)
- return -EINVAL;
-
- /* only supports note that fits in the first page */
- if (note_start + note_size > page_addr + PAGE_SIZE)
- return -EINVAL;
-
- while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
- Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
-
- if (nhdr->n_type == BPF_BUILD_ID &&
- nhdr->n_namesz == sizeof("GNU") &&
- nhdr->n_descsz > 0 &&
- nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
- memcpy(build_id,
- note_start + note_offs +
- ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
- nhdr->n_descsz);
- memset(build_id + nhdr->n_descsz, 0,
- BPF_BUILD_ID_SIZE - nhdr->n_descsz);
- return 0;
- }
- new_offs = note_offs + sizeof(Elf32_Nhdr) +
- ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
- if (new_offs <= note_offs) /* overflow */
- break;
- note_offs = new_offs;
- }
- return -EINVAL;
-}
-
-/* Parse build ID from 32-bit ELF */
-static int stack_map_get_build_id_32(void *page_addr,
- unsigned char *build_id)
-{
- Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
- Elf32_Phdr *phdr;
- int i;
-
- /* only supports phdr that fits in one page */
- if (ehdr->e_phnum >
- (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
- return -EINVAL;
-
- phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
-
- for (i = 0; i < ehdr->e_phnum; ++i) {
- if (phdr[i].p_type == PT_NOTE &&
- !stack_map_parse_build_id(page_addr, build_id,
- page_addr + phdr[i].p_offset,
- phdr[i].p_filesz))
- return 0;
- }
- return -EINVAL;
-}
-
-/* Parse build ID from 64-bit ELF */
-static int stack_map_get_build_id_64(void *page_addr,
- unsigned char *build_id)
-{
- Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
- Elf64_Phdr *phdr;
- int i;
-
- /* only supports phdr that fits in one page */
- if (ehdr->e_phnum >
- (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
- return -EINVAL;
-
- phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
-
- for (i = 0; i < ehdr->e_phnum; ++i) {
- if (phdr[i].p_type == PT_NOTE &&
- !stack_map_parse_build_id(page_addr, build_id,
- page_addr + phdr[i].p_offset,
- phdr[i].p_filesz))
- return 0;
- }
- return -EINVAL;
-}
-
-/* Parse build ID of ELF file mapped to vma */
-static int stack_map_get_build_id(struct vm_area_struct *vma,
- unsigned char *build_id)
-{
- Elf32_Ehdr *ehdr;
- struct page *page;
- void *page_addr;
- int ret;
-
- /* only works for page backed storage */
- if (!vma->vm_file)
- return -EINVAL;
-
- page = find_get_page(vma->vm_file->f_mapping, 0);
- if (!page)
- return -EFAULT; /* page not mapped */
-
- ret = -EINVAL;
- page_addr = kmap_atomic(page);
- ehdr = (Elf32_Ehdr *)page_addr;
-
- /* compare magic x7f "ELF" */
- if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
- goto out;
-
- /* only support executable file and shared object file */
- if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
- goto out;
-
- if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
- ret = stack_map_get_build_id_32(page_addr, build_id);
- else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
- ret = stack_map_get_build_id_64(page_addr, build_id);
-out:
- kunmap_atomic(page_addr);
- put_page(page);
- return ret;
-}
-
static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
u64 *ips, u32 trace_nr, bool user)
{
@@ -327,18 +192,18 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
for (i = 0; i < trace_nr; i++) {
id_offs[i].status = BPF_STACK_BUILD_ID_IP;
id_offs[i].ip = ips[i];
- memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
+ memset(id_offs[i].build_id, 0, BUILD_ID_SIZE);
}
return;
}
for (i = 0; i < trace_nr; i++) {
vma = find_vma(current->mm, ips[i]);
- if (!vma || stack_map_get_build_id(vma, id_offs[i].build_id)) {
+ if (!vma || build_id_parse(vma, id_offs[i].build_id)) {
/* per entry fall back to ips */
id_offs[i].status = BPF_STACK_BUILD_ID_IP;
id_offs[i].ip = ips[i];
- memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
+ memset(id_offs[i].build_id, 0, BUILD_ID_SIZE);
continue;
}
id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
diff --git a/lib/Makefile b/lib/Makefile
index ce45af50983a..f4858f5e9215 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -36,7 +36,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
flex_proportions.o ratelimit.o show_mem.o \
is_single_threaded.o plist.o decompress.o kobject_uevent.o \
earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
- nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o
+ nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o \
+ buildid.o
lib-$(CONFIG_PRINTK) += dump_stack.o
lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/buildid.c b/lib/buildid.c
new file mode 100644
index 000000000000..e8d5feb7ef20
--- /dev/null
+++ b/lib/buildid.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/buildid.h>
+#include <linux/elf.h>
+#include <linux/pagemap.h>
+
+#define BUILD_ID 3
+/*
+ * Parse build id from the note segment. This logic can be shared between
+ * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
+ * identical.
+ */
+static inline int parse_build_id(void *page_addr,
+ unsigned char *build_id,
+ void *note_start,
+ Elf32_Word note_size)
+{
+ Elf32_Word note_offs = 0, new_offs;
+
+ /* check for overflow */
+ if (note_start < page_addr || note_start + note_size < note_start)
+ return -EINVAL;
+
+ /* only supports note that fits in the first page */
+ if (note_start + note_size > page_addr + PAGE_SIZE)
+ return -EINVAL;
+
+ while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
+ Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
+
+ if (nhdr->n_type == BUILD_ID &&
+ nhdr->n_namesz == sizeof("GNU") &&
+ nhdr->n_descsz > 0 &&
+ nhdr->n_descsz <= BUILD_ID_SIZE) {
+ memcpy(build_id,
+ note_start + note_offs +
+ ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
+ nhdr->n_descsz);
+ memset(build_id + nhdr->n_descsz, 0,
+ BUILD_ID_SIZE - nhdr->n_descsz);
+ return 0;
+ }
+ new_offs = note_offs + sizeof(Elf32_Nhdr) +
+ ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
+ if (new_offs <= note_offs) /* overflow */
+ break;
+ note_offs = new_offs;
+ }
+ return -EINVAL;
+}
+
+/* Parse build ID from 32-bit ELF */
+static int get_build_id_32(void *page_addr, unsigned char *build_id)
+{
+ Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
+ Elf32_Phdr *phdr;
+ int i;
+
+ /* only supports phdr that fits in one page */
+ if (ehdr->e_phnum >
+ (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
+ return -EINVAL;
+
+ phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
+
+ for (i = 0; i < ehdr->e_phnum; ++i) {
+ if (phdr[i].p_type == PT_NOTE &&
+ !parse_build_id(page_addr, build_id,
+ page_addr + phdr[i].p_offset,
+ phdr[i].p_filesz))
+ return 0;
+ }
+ return -EINVAL;
+}
+
+/* Parse build ID from 64-bit ELF */
+static int get_build_id_64(void *page_addr, unsigned char *build_id)
+{
+ Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
+ Elf64_Phdr *phdr;
+ int i;
+
+ /* only supports phdr that fits in one page */
+ if (ehdr->e_phnum >
+ (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
+ return -EINVAL;
+
+ phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
+
+ for (i = 0; i < ehdr->e_phnum; ++i) {
+ if (phdr[i].p_type == PT_NOTE &&
+ !parse_build_id(page_addr, build_id,
+ page_addr + phdr[i].p_offset,
+ phdr[i].p_filesz))
+ return 0;
+ }
+ return -EINVAL;
+}
+
+/* Parse build ID of ELF file mapped to vma */
+int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id)
+{
+ Elf32_Ehdr *ehdr;
+ struct page *page;
+ void *page_addr;
+ int ret;
+
+ /* only works for page backed storage */
+ if (!vma->vm_file)
+ return -EINVAL;
+
+ page = find_get_page(vma->vm_file->f_mapping, 0);
+ if (!page)
+ return -EFAULT; /* page not mapped */
+
+ ret = -EINVAL;
+ page_addr = kmap_atomic(page);
+ ehdr = (Elf32_Ehdr *)page_addr;
+
+ /* compare magic x7f "ELF" */
+ if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
+ goto out;
+
+ /* only support executable file and shared object file */
+ if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
+ goto out;
+
+ if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
+ ret = get_build_id_32(page_addr, build_id);
+ else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
+ ret = get_build_id_64(page_addr, build_id);
+out:
+ kunmap_atomic(page_addr);
+ put_page(page);
+ return ret;
+}
--
2.26.2
next prev parent reply other threads:[~2020-11-26 17:01 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 17:00 [PATCHv4 00/25] perf: Add mmap2 build id support Jiri Olsa
2020-11-26 17:00 ` Jiri Olsa [this message]
2020-11-26 17:00 ` [PATCH 02/25] bpf: Add size arg to build_id_parse function Jiri Olsa
2020-12-03 19:24 ` Jiri Olsa
2020-12-03 21:23 ` Song Liu
2020-12-04 23:30 ` Jiri Olsa
2020-11-26 17:00 ` [PATCH 03/25] perf: Add build id data in mmap2 event Jiri Olsa
2020-11-26 17:00 ` [PATCH 04/25] tools headers uapi: Sync tools/include/uapi/linux/perf_event.h Jiri Olsa
2020-11-26 17:00 ` [PATCH 05/25] tools lib: Adopt memchr_inv() from kernel Jiri Olsa
2020-11-26 17:42 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 06/25] perf tools: Do not swap mmap2 fields in case it contains build id Jiri Olsa
2020-11-26 17:30 ` Arnaldo Carvalho de Melo
2020-11-27 19:46 ` Jiri Olsa
2020-11-26 17:00 ` [PATCH 07/25] perf tools: Add build_id__is_defined function Jiri Olsa
2020-11-26 17:43 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 08/25] perf tools: Add filename__decompress function Jiri Olsa
2020-11-26 17:44 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 09/25] perf tools: Add support to read build id from compressed elf Jiri Olsa
2020-11-26 17:46 ` Arnaldo Carvalho de Melo
2020-11-27 19:45 ` Jiri Olsa
2020-11-26 17:00 ` [PATCH 10/25] perf tools: Add check for existing link in buildid dir Jiri Olsa
2020-11-26 17:47 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 11/25] perf tools: Use struct extra_kernel_map in machine__process_kernel_mmap_event Jiri Olsa
2020-11-26 17:48 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 12/25] perf tools: Try to load vmlinux from buildid database Jiri Olsa
2020-11-26 17:50 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 13/25] perf tools: Store build id from mmap2 events Jiri Olsa
2020-11-26 17:00 ` [PATCH 14/25] perf tools: Allow mmap2 event to synthesize kernel image Jiri Olsa
2020-11-26 17:00 ` [PATCH 15/25] perf tools: Allow mmap2 event to synthesize modules Jiri Olsa
2020-11-26 17:00 ` [PATCH 16/25] perf tools: Synthesize build id for kernel/modules/tasks Jiri Olsa
2020-11-26 17:00 ` [PATCH 17/25] perf tools: Add support to display build id for mmap2 events Jiri Olsa
2020-11-26 17:00 ` [PATCH 18/25] perf tools: Use machine__for_each_dso in perf_session__cache_build_ids Jiri Olsa
2020-11-26 17:52 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 19/25] perf tools: Add __perf_session__cache_build_ids function Jiri Olsa
2020-11-26 17:53 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 20/25] perf tools: Add is_perf_data function Jiri Olsa
2020-11-26 17:51 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 21/25] perf tools: Add build_id_cache__add function Jiri Olsa
2020-11-26 17:53 ` Arnaldo Carvalho de Melo
2020-11-26 17:00 ` [PATCH 22/25] perf buildid-cache: Add support to add build ids from perf data Jiri Olsa
2020-11-26 17:57 ` Arnaldo Carvalho de Melo
2020-11-27 19:49 ` Jiri Olsa
2020-11-26 17:00 ` [PATCH 23/25] perf buildid-cache: Add --debuginfod option Jiri Olsa
2020-11-26 17:00 ` [PATCH 24/25] perf buildid-list: Add support for mmap2's buildid events Jiri Olsa
2020-11-26 17:00 ` [PATCH 25/25] perf record: Add --buildid-mmap option to enable mmap's build id Jiri Olsa
2020-11-26 17:40 ` Arnaldo Carvalho de Melo
2020-11-27 4:41 ` [PATCHv4 00/25] perf: Add mmap2 build id support Namhyung Kim
-- strict thread matches above, loose matches on Subject: below --
2020-11-23 23:04 [PATCHv3 " Jiri Olsa
2020-11-23 23:04 ` [PATCH 01/25] bpf: Move stack_map_get_build_id into lib Jiri Olsa
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