From 20c080830b6f538366d7ff18b64de704dd551e61 Mon Sep 17 00:00:00 2001
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Date: Fri, 1 Jul 2022 13:04:04 +0530
Subject: [PATCH] kexec_file: drop weak attribute from functions

References: bsc#1196444
Patch-mainline: v6.0-rc1
Git-commit: 65d9a9a60fd71be964effb2e94747a6acb6e7015

As requested
(http://lkml.kernel.org/r/87ee0q7b92.fsf@email.froward.int.ebiederm.org),
this series converts weak functions in kexec to use the #ifdef approach.

Quoting the 3e35142ef99fe ("kexec_file: drop weak attribute from
arch_kexec_apply_relocations[_add]") changelog:

: 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.

This patch (of 2);

Drop __weak attribute from functions in kexec_file.c:
- arch_kexec_kernel_image_probe()
- arch_kimage_file_post_load_cleanup()
- arch_kexec_kernel_image_load()
- arch_kexec_locate_mem_hole()
- arch_kexec_kernel_verify_sig()

arch_kexec_kernel_image_load() calls into kexec_image_load_default(), so
drop the static attribute for the latter.

arch_kexec_kernel_verify_sig() is not overridden by any architecture, so
drop the __weak attribute.

Link: https://lkml.kernel.org/r/cover.1656659357.git.naveen.n.rao@linux.vnet.ibm.com
Link: https://lkml.kernel.org/r/2cd7ca1fe4d6bb6ca38e3283c717878388ed6788.1656659357.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Suggested-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Note: before commit 277c8389386e ("s390/kexec_file: move kernel image size check")
in v 5.16 there is an additional intance of arch_kexec_kernel_image_probe on s390
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/arm64/include/asm/kexec.h   |  4 ++-
 arch/powerpc/include/asm/kexec.h |  9 +++++++
 arch/s390/include/asm/kexec.h    |  6 +++++
 arch/x86/include/asm/kexec.h     |  6 +++++
 include/linux/kexec.h            | 44 +++++++++++++++++++++++++++-----
 kernel/kexec_file.c              | 35 ++-----------------------
 6 files changed, 64 insertions(+), 40 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..6db1051653a4 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -106,7 +106,9 @@ extern const struct kexec_file_ops kexec_image_ops;
 
 struct kimage;
 
-extern int arch_kimage_file_post_load_cleanup(struct kimage *image);
+int arch_kimage_file_post_load_cleanup(struct kimage *image);
+#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
+
 extern int load_other_segments(struct kimage *image,
 		unsigned long kernel_load_addr, unsigned long kernel_size,
 		char *initrd, unsigned long initrd_len,
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 9ab344d29a54..eb3ea43c5646 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -131,6 +131,15 @@ int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
 #ifdef CONFIG_PPC64
 struct kexec_buf;
 
+int arch_kexec_kernel_image_probe(struct kimage *image, void *buf, unsigned long buf_len);
+#define arch_kexec_kernel_image_probe arch_kexec_kernel_image_probe
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image);
+#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
+
+int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
+#define arch_kexec_locate_mem_hole arch_kexec_locate_mem_hole
+
 int load_crashdump_segments_ppc64(struct kimage *image,
 				  struct kexec_buf *kbuf);
 int setup_purgatory_ppc64(struct kimage *image, const void *slave_code,
diff --git a/arch/s390/include/asm/kexec.h b/arch/s390/include/asm/kexec.h
index 63098df81c9f..407b649ca519 100644
--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -92,5 +92,11 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 				     const Elf_Shdr *relsec,
 				     const Elf_Shdr *symtab);
 #define arch_kexec_apply_relocations_add arch_kexec_apply_relocations_add
+
+int arch_kexec_kernel_image_probe(struct kimage *image, void *buf, unsigned long buf_len);
+#define arch_kexec_kernel_image_probe arch_kexec_kernel_image_probe
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image);
+#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
 #endif
 #endif /*_S390_KEXEC_H */
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index e5fba0be9497..08b7a73083d4 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -211,6 +211,12 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 				     const Elf_Shdr *relsec,
 				     const Elf_Shdr *symtab);
 #define arch_kexec_apply_relocations_add arch_kexec_apply_relocations_add
+
+void *arch_kexec_kernel_image_load(struct kimage *image);
+#define arch_kexec_kernel_image_load arch_kexec_kernel_image_load
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image);
+#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup
 #endif
 #endif
 
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d76967af6672..422eaa63a0a6 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -182,21 +182,53 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
 				   void *buf, unsigned int size,
 				   bool get_value);
 void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name);
+void *kexec_image_load_default(struct kimage *image);
+
+#ifndef arch_kexec_kernel_image_probe
+static inline int
+arch_kexec_kernel_image_probe(struct kimage *image, void *buf, unsigned long buf_len)
+{
+	return kexec_image_probe_default(image, buf, buf_len);
+}
+#endif
+
+#ifndef arch_kimage_file_post_load_cleanup
+static inline int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+	return kexec_image_post_load_cleanup_default(image);
+}
+#endif
+
+#ifndef arch_kexec_kernel_image_load
+static inline void *arch_kexec_kernel_image_load(struct kimage *image)
+{
+	return kexec_image_load_default(image);
+}
+#endif
 
-/* Architectures may override the below functions */
-int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
-				  unsigned long buf_len);
-void *arch_kexec_kernel_image_load(struct kimage *image);
-int arch_kimage_file_post_load_cleanup(struct kimage *image);
 #ifdef CONFIG_KEXEC_SIG
 int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
 				 unsigned long buf_len);
 #endif
-int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
 
 extern int kexec_add_buffer(struct kexec_buf *kbuf);
 int kexec_locate_mem_hole(struct kexec_buf *kbuf);
 
+#ifndef arch_kexec_locate_mem_hole
+/**
+ * arch_kexec_locate_mem_hole - Find free memory to place the segments.
+ * @kbuf:                       Parameters for the memory search.
+ *
+ * On success, kbuf->mem will have the start address of the memory region found.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static inline int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
+{
+	return kexec_locate_mem_hole(kbuf);
+}
+#endif
+
 /* Alignment required for elf header segment */
 #define ELF_CORE_HEADER_ALIGN   4096
 
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 383fc13796b8..d6ecfc337744 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -52,14 +52,7 @@ int kexec_image_probe_default(struct kimage *image, void *buf,
 	return ret;
 }
 
-/* Architectures can provide this probe function */
-int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
-					 unsigned long buf_len)
-{
-	return kexec_image_probe_default(image, buf, buf_len);
-}
-
-static void *kexec_image_load_default(struct kimage *image)
+void *kexec_image_load_default(struct kimage *image)
 {
 	if (!image->fops || !image->fops->load)
 		return ERR_PTR(-ENOEXEC);
@@ -70,11 +63,6 @@ static void *kexec_image_load_default(struct kimage *image)
 				 image->cmdline_buf_len);
 }
 
-void * __weak arch_kexec_kernel_image_load(struct kimage *image)
-{
-	return kexec_image_load_default(image);
-}
-
 int kexec_image_post_load_cleanup_default(struct kimage *image)
 {
 	if (!image->fops || !image->fops->cleanup)
@@ -83,11 +71,6 @@ int kexec_image_post_load_cleanup_default(struct kimage *image)
 	return image->fops->cleanup(image->image_loader_data);
 }
 
-int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
-{
-	return kexec_image_post_load_cleanup_default(image);
-}
-
 #ifdef CONFIG_KEXEC_SIG
 static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
 					  unsigned long buf_len)
@@ -100,8 +83,7 @@ static int kexec_image_verify_sig_default(struct kimage *image, void *buf,
 	return image->fops->verify_sig(buf, buf_len);
 }
 
-int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
-					unsigned long buf_len)
+int arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, unsigned long buf_len)
 {
 	return kexec_image_verify_sig_default(image, buf, buf_len);
 }
@@ -619,19 +601,6 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
 	return ret == 1 ? 0 : -EADDRNOTAVAIL;
 }
 
-/**
- * arch_kexec_locate_mem_hole - Find free memory to place the segments.
- * @kbuf:                       Parameters for the memory search.
- *
- * On success, kbuf->mem will have the start address of the memory region found.
- *
- * Return: 0 on success, negative errno on error.
- */
-int __weak arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
-{
-	return kexec_locate_mem_hole(kbuf);
-}
-
 /**
  * kexec_add_buffer - place a buffer in a kexec segment
  * @kbuf:	Buffer contents and memory parameters.
-- 
2.35.3