kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add]

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@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@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/include/asm/kexec.h b/arch/s390/include/asm/kexec.h
index 825dd0f7f2211863a5b127c193220f4c6556dfa4..ba9b0e76470c524e7d19ea0697342661974fb363 100644 (file)
--- 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>
 /*
@@ -69,4 +71,12 @@ int *kexec_file_update_kernel(struct kimage *iamge,
 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 5125fca472bb0b44dc8baab1a00e719096e0d8e3..0a41c62369f2cb4e5c1d7917294cdd74957251bb 100644 (file)
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -21,6 +21,7 @@
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
+#include <linux/module.h>
 
 #include <asm/page.h>
 #include <asm/ptrace.h>
@@ -217,6 +218,14 @@ 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 fe9f6f2dd811d2af2484edc74d0538f815082670..29bffbc6d73aa7653d0c02fad87f3d0944329e45 100644 (file)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -174,14 +174,6 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
                                   bool get_value);
 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name);
 
-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);
 
 int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
                               int (*func)(struct resource *, void *));
@@ -206,6 +198,44 @@ 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 */
 
 struct kimage {

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 89d41c0a10f1e5bcba616df508081fad8b3f055b..ab1934a2b2e6e90e201a287a13ad02c9085f5d8a 100644 (file)
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -110,40 +110,6 @@ 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