2024-04-09 15:04:15

by Ard Biesheuvel

Subject: [PATCH v2 2/3] vmlinux: Avoid weak reference to notes section

From: Ard Biesheuvel <[email protected]>

Weak references are references that are permitted to remain unsatisfied
in the final link. This means they cannot be implemented using place
relative relocations, resulting in GOT entries when using position
independent code generation.

The notes section should always exist, so the weak annotations can be
omitted.

Signed-off-by: Ard Biesheuvel <[email protected]>
---
kernel/ksysfs.c | 4 ++--
lib/buildid.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 495b69a71a5d..07fb5987b42b 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -228,8 +228,8 @@ KERNEL_ATTR_RW(rcu_normal);
/*
* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
*/
-extern const void __start_notes __weak;
-extern const void __stop_notes __weak;
+extern const void __start_notes;
+extern const void __stop_notes;
#define notes_size (&__stop_notes - &__start_notes)

static ssize_t notes_read(struct file *filp, struct kobject *kobj,
diff --git a/lib/buildid.c b/lib/buildid.c
index 898301b49eb6..7954dd92e36c 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -182,8 +182,8 @@ unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
*/
void __init init_vmlinux_build_id(void)
{
- extern const void __start_notes __weak;
- extern const void __stop_notes __weak;
+ extern const void __start_notes;
+ extern const void __stop_notes;
unsigned int size = &__stop_notes - &__start_notes;

build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
--
2.44.0.478.gd926399ef9-goog

2024-04-09 15:34:24

by Arnd Bergmann

Subject: Re: [PATCH v2 2/3] vmlinux: Avoid weak reference to notes section

On Tue, Apr 9, 2024, at 17:01, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <[email protected]>
>
> Weak references are references that are permitted to remain unsatisfied
> in the final link. This means they cannot be implemented using place
> relative relocations, resulting in GOT entries when using position
> independent code generation.
>
> The notes section should always exist, so the weak annotations can be
> omitted.
>
> Signed-off-by: Ard Biesheuvel <[email protected]>

Acked-by: Arnd Bergmann <[email protected]>