commit 3e35142ef99fe6b4fe5d834ad43ee13cca10a2dc upstream.
Since commit d1bcae833b32f1 ("ELF: Don't generate unused section
symbols") [1], binutils (v2.36+) started dropping section symbols that
it thought were unused. This isn't an issue in general, but with
kexec_file.c, gcc is placing kexec_arch_apply_relocations[_add] into a
separate .text.unlikely section and the section symbol ".text.unlikely"
is being dropped. Due to this, recordmcount is unable to find a non-weak
symbol in .text.unlikely to generate a relocation record against.
Address this by dropping the weak attribute from these functions.
Instead, follow the existing pattern of having architectures #define the
name of the function they want to override in their headers.
[1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1
[[email protected]: arch/s390/include/asm/kexec.h needs linux/module.h]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Naveen N. Rao <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
arch/x86/include/asm/kexec.h | 7 +++++++
include/linux/kexec.h | 26 ++++++++++++++++++++++----
kernel/kexec_file.c | 18 ------------------
3 files changed, 29 insertions(+), 22 deletions(-)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 1624a7ffa95d89..3f1f58c1a9ce63 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -20,6 +20,7 @@
#ifndef __ASSEMBLY__
#include <linux/string.h>
+#include <linux/module.h>
#include <asm/page.h>
#include <asm/ptrace.h>
@@ -206,6 +207,12 @@ struct kexec_entry64_regs {
uint64_t r15;
uint64_t rip;
};
+
+#ifdef CONFIG_KEXEC_FILE
+int arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
+ Elf_Shdr *sechdrs, unsigned int relsec);
+#define arch_kexec_apply_relocations_add arch_kexec_apply_relocations_add
+#endif
#endif
typedef void crash_vmclear_fn(void);
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 406c33dcae137a..565be657098b0b 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -148,6 +148,28 @@ struct kexec_file_ops {
kexec_verify_sig_t *verify_sig;
#endif
};
+
+#ifndef arch_kexec_apply_relocations_add
+/* Apply relocations of type RELA */
+static inline int
+arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
+ Elf_Shdr *sechdrs, unsigned int relsec)
+{
+ pr_err("RELA relocation unsupported.\n");
+ return -ENOEXEC;
+}
+#endif
+
+#ifndef arch_kexec_apply_relocations
+/* Apply relocations of type REL */
+static inline int
+arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
+ unsigned int relsec)
+{
+ pr_err("REL relocation unsupported.\n");
+ return -ENOEXEC;
+}
+#endif
#endif
struct kimage {
@@ -320,10 +342,6 @@ void * __weak arch_kexec_kernel_image_load(struct kimage *image);
int __weak arch_kimage_file_post_load_cleanup(struct kimage *image);
int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
unsigned long buf_len);
-int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
- Elf_Shdr *sechdrs, unsigned int relsec);
-int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
- unsigned int relsec);
void arch_kexec_protect_crashkres(void);
void arch_kexec_unprotect_crashkres(void);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 2edaed6803ff79..eb775e699836ad 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -59,24 +59,6 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
}
#endif
-/* Apply relocations of type RELA */
-int __weak
-arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
- unsigned int relsec)
-{
- pr_err("RELA relocation unsupported.\n");
- return -ENOEXEC;
-}
-
-/* Apply relocations of type REL */
-int __weak
-arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
- unsigned int relsec)
-{
- pr_err("REL relocation unsupported.\n");
- return -ENOEXEC;
-}
-
/*
* Free up memory used by kernel, initrd, and command line. This is temporary
* memory allocation which is not needed any more after these buffers have
base-commit: 4ffa4be5a14beeb008bd2b4fbc681222bfec90c7
--
2.36.1
On Tue, Jun 28, 2022 at 09:12:48PM +0530, Naveen N. Rao wrote:
> commit 3e35142ef99fe6b4fe5d834ad43ee13cca10a2dc upstream.
>
> Since commit d1bcae833b32f1 ("ELF: Don't generate unused section
> symbols") [1], binutils (v2.36+) started dropping section symbols that
> it thought were unused. This isn't an issue in general, but with
> kexec_file.c, gcc is placing kexec_arch_apply_relocations[_add] into a
> separate .text.unlikely section and the section symbol ".text.unlikely"
> is being dropped. Due to this, recordmcount is unable to find a non-weak
> symbol in .text.unlikely to generate a relocation record against.
>
> Address this by dropping the weak attribute from these functions.
> Instead, follow the existing pattern of having architectures #define the
> name of the function they want to override in their headers.
>
> [1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1
>
> [[email protected]: arch/s390/include/asm/kexec.h needs linux/module.h]
> Link: https://lkml.kernel.org/r/[email protected]
> Signed-off-by: Michael Ellerman <[email protected]>
> Signed-off-by: Naveen N. Rao <[email protected]>
> Cc: "Eric W. Biederman" <[email protected]>
> Cc: <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
> ---
> arch/x86/include/asm/kexec.h | 7 +++++++
> include/linux/kexec.h | 26 ++++++++++++++++++++++----
> kernel/kexec_file.c | 18 ------------------
> 3 files changed, 29 insertions(+), 22 deletions(-)
>
All now queued up, thanks.
greg k-h