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Commit 24f3fca3 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Greg Kroah-Hartman
Browse files

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: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8ad86015

arch/s390/include/asm/kexec.h

+10 −0
Original line number Diff line number Diff line
@@ -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 */

arch/x86/include/asm/kexec.h

+9 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/kexec.h

+38 −8
Original line number Diff line number Diff line
@@ -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 {

kernel/kexec_file.c

+0 −34
Original line number Diff line number Diff line
@@ -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