Re: [PATCH v3 02/12] buildid: Stash away kernels build ID on init

[Stephen Boyd]

Quoting Jessica Yu (2021-04-08 05:05:33)
> +++ Stephen Boyd [30/03/21 20:05 -0700]:
> >+/**
> >+ * init_vmlinux_build_id - Get the running kernel's build ID
> >+ *
> >+ * Return: Running kernel's build ID
> >+ */
> 
> Hm, init_vmlinux_build_id() doesn't return anything, so this comment is
> not accurate - maybe "Get the running kernel's build ID and store it in
> vmlinux_build_id"?
> 
> >+void __init init_vmlinux_build_id(void)

Thanks! I've fixed it for the next round.

Re: [PATCH v3 02/12] buildid: Stash away kernels build ID on init

[Jessica Yu]

+++ Stephen Boyd [30/03/21 20:05 -0700]:
[snipped]

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 
+#include 
#include 
#include 
#include 
@@ -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
+ */


Hm, init_vmlinux_build_id() doesn't return anything, so this comment is
not accurate - maybe "Get the running kernel's build ID and store it in
vmlinux_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);
+}

[PATCH v3 02/12] buildid: Stash away kernels build ID on init

[Stephen Boyd]

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 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Dave Young 
Cc: Baoquan He 
Cc: Vivek Goyal 
Cc: 
Signed-off-by: Stephen Boyd 
---
 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(_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 
+#include 
 #include 
 #include 
 #include 
@@ -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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