[PATCH v5.4] kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add]
Naveen N. Rao
naveen.n.rao at linux.vnet.ibm.com
Wed Jun 29 01:42:49 AEST 2022
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
[akpm at linux-foundation.org: arch/s390/include/asm/kexec.h needs linux/module.h]
Link: https://lkml.kernel.org/r/20220519091237.676736-1-naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm at xmission.com>
Cc: <stable at vger.kernel.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---
arch/s390/include/asm/kexec.h | 10 ++++++++
arch/x86/include/asm/kexec.h | 9 +++++++
include/linux/kexec.h | 46 +++++++++++++++++++++++++++++------
kernel/kexec_file.c | 34 --------------------------
4 files changed, 57 insertions(+), 42 deletions(-)
diff --git a/arch/s390/include/asm/kexec.h b/arch/s390/include/asm/kexec.h
index 7f3c9ac34bd8d1..63098df81c9f2a 100644
--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -9,6 +9,8 @@
#ifndef _S390_KEXEC_H
#define _S390_KEXEC_H
+#include <linux/module.h>
+
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/setup.h>
@@ -83,4 +85,12 @@ struct kimage_arch {
extern const struct kexec_file_ops s390_kexec_image_ops;
extern const struct kexec_file_ops s390_kexec_elf_ops;
+#ifdef CONFIG_KEXEC_FILE
+struct purgatory_info;
+int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
+ Elf_Shdr *section,
+ const Elf_Shdr *relsec,
+ const Elf_Shdr *symtab);
+#define arch_kexec_apply_relocations_add arch_kexec_apply_relocations_add
+#endif
#endif /*_S390_KEXEC_H */
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 5e7d6b46de97d6..367da081f7d9d9 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -22,6 +22,7 @@
#include <linux/string.h>
#include <linux/kernel.h>
+#include <linux/module.h>
#include <asm/page.h>
#include <asm/ptrace.h>
@@ -201,6 +202,14 @@ extern int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages,
extern void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages);
#define arch_kexec_pre_free_pages arch_kexec_pre_free_pages
+#ifdef CONFIG_KEXEC_FILE
+struct purgatory_info;
+int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
+ Elf_Shdr *section,
+ const Elf_Shdr *relsec,
+ const Elf_Shdr *symtab);
+#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 a1cffce3de8cd7..64f23bab6255da 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -186,14 +186,6 @@ void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name);
int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
unsigned long buf_len);
void * __weak arch_kexec_kernel_image_load(struct kimage *image);
-int __weak arch_kexec_apply_relocations_add(struct purgatory_info *pi,
- Elf_Shdr *section,
- const Elf_Shdr *relsec,
- const Elf_Shdr *symtab);
-int __weak arch_kexec_apply_relocations(struct purgatory_info *pi,
- Elf_Shdr *section,
- const Elf_Shdr *relsec,
- const Elf_Shdr *symtab);
extern int kexec_add_buffer(struct kexec_buf *kbuf);
int kexec_locate_mem_hole(struct kexec_buf *kbuf);
@@ -216,6 +208,44 @@ extern int crash_exclude_mem_range(struct crash_mem *mem,
unsigned long long mend);
extern int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map,
void **addr, unsigned long *sz);
+
+#ifndef arch_kexec_apply_relocations_add
+/*
+ * arch_kexec_apply_relocations_add - apply relocations of type RELA
+ * @pi: Purgatory to be relocated.
+ * @section: Section relocations applying to.
+ * @relsec: Section containing RELAs.
+ * @symtab: Corresponding symtab.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static inline int
+arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
+ const Elf_Shdr *relsec, const Elf_Shdr *symtab)
+{
+ pr_err("RELA relocation unsupported.\n");
+ return -ENOEXEC;
+}
+#endif
+
+#ifndef arch_kexec_apply_relocations
+/*
+ * arch_kexec_apply_relocations - apply relocations of type REL
+ * @pi: Purgatory to be relocated.
+ * @section: Section relocations applying to.
+ * @relsec: Section containing RELs.
+ * @symtab: Corresponding symtab.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static inline int
+arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
+ const Elf_Shdr *relsec, const Elf_Shdr *symtab)
+{
+ pr_err("REL relocation unsupported.\n");
+ return -ENOEXEC;
+}
+#endif
#endif /* CONFIG_KEXEC_FILE */
#ifdef CONFIG_KEXEC_ELF
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b17998fa03f125..5b58149bcd900b 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -107,40 +107,6 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
}
#endif
-/*
- * arch_kexec_apply_relocations_add - apply relocations of type RELA
- * @pi: Purgatory to be relocated.
- * @section: Section relocations applying to.
- * @relsec: Section containing RELAs.
- * @symtab: Corresponding symtab.
- *
- * Return: 0 on success, negative errno on error.
- */
-int __weak
-arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section,
- const Elf_Shdr *relsec, const Elf_Shdr *symtab)
-{
- pr_err("RELA relocation unsupported.\n");
- return -ENOEXEC;
-}
-
-/*
- * arch_kexec_apply_relocations - apply relocations of type REL
- * @pi: Purgatory to be relocated.
- * @section: Section relocations applying to.
- * @relsec: Section containing RELs.
- * @symtab: Corresponding symtab.
- *
- * Return: 0 on success, negative errno on error.
- */
-int __weak
-arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
- const Elf_Shdr *relsec, const Elf_Shdr *symtab)
-{
- 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: 23db944f754e99abf814a79a2273b0191d35e4ff
--
2.36.1
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