[PATCH v3 02/12] buildid: Stash away kernels build ID on init
Stephen Boyd
swboyd at chromium.org
Wed Mar 31 04:05:10 BST 2021
Parse the kernel's build ID at initialization so that other code can
print a hex format string representation of the running kernel's build
ID. This will be used in the kdump and dump_stack code so that
developers can easily locate the vmlinux debug symbols for a
crash/stacktrace.
Cc: Jiri Olsa <jolsa at kernel.org>
Cc: Alexei Starovoitov <ast at kernel.org>
Cc: Jessica Yu <jeyu at kernel.org>
Cc: Evan Green <evgreen at chromium.org>
Cc: Hsin-Yi Wang <hsinyi at chromium.org>
Cc: Dave Young <dyoung at redhat.com>
Cc: Baoquan He <bhe at redhat.com>
Cc: Vivek Goyal <vgoyal at redhat.com>
Cc: <kexec at lists.infradead.org>
Signed-off-by: Stephen Boyd <swboyd at chromium.org>
---
include/linux/buildid.h | 3 +++
init/main.c | 1 +
lib/buildid.c | 17 +++++++++++++++++
3 files changed, 21 insertions(+)
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index ebce93f26d06..0312660089c3 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -10,4 +10,7 @@ int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
__u32 *size);
int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size);
+extern unsigned char vmlinux_build_id[];
+void init_vmlinux_build_id(void);
+
#endif
diff --git a/init/main.c b/init/main.c
index 53b278845b88..eaede2f41327 100644
--- a/init/main.c
+++ b/init/main.c
@@ -857,6 +857,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
set_task_stack_end_magic(&init_task);
smp_setup_processor_id();
debug_objects_early_init();
+ init_vmlinux_build_id();
cgroup_init_early();
diff --git a/lib/buildid.c b/lib/buildid.c
index 010ab0674cb9..b939bbc59233 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/buildid.h>
+#include <linux/cache.h>
#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
@@ -171,3 +172,19 @@ int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
{
return parse_build_id_buf(build_id, NULL, buf, buf_size);
}
+
+unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
+
+/**
+ * init_vmlinux_build_id - Get the running kernel's build ID
+ *
+ * Return: Running kernel's build ID
+ */
+void __init init_vmlinux_build_id(void)
+{
+ extern const void __start_notes __weak;
+ extern const void __stop_notes __weak;
+ unsigned int size = &__stop_notes - &__start_notes;
+
+ build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
+}
--
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