Thread (15 messages) 15 messages, 4 authors, 2022-09-27
STALE1396d

[PATCH 5.15 2/6] kexec_file: drop weak attribute from functions

From: Michal Suchanek <hidden>
Date: 2022-09-23 17:11:05
Also in: kexec, linux-s390, linuxppc-dev, lkml, stable
Subsystem: arm64 port (aarch64 architecture), kexec, linux for powerpc (32-bit and 64-bit), s390 architecture, the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Catalin Marinas, Will Deacon, Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Madhavan Srinivasan, Michael Ellerman, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

From: "Naveen N. Rao" <redacted>

commit 65d9a9a60fd71be964effb2e94747a6acb6e7015 upstream.

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 <redacted>
Suggested-by: Eric Biederman <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Michal Suchanek <redacted>
---
 arch/arm64/include/asm/kexec.h   |  4 ++-
 arch/powerpc/include/asm/kexec.h |  9 +++++++
 arch/s390/include/asm/kexec.h    |  3 +++
 arch/x86/include/asm/kexec.h     |  6 +++++
 include/linux/kexec.h            | 44 +++++++++++++++++++++++++++-----
 kernel/kexec_file.c              | 35 ++-----------------------
 6 files changed, 61 insertions(+), 40 deletions(-)
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 00dbcc71aeb2..91d81824f869 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -103,7 +103,9 @@ 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 88d0d7cf3a79..6152fa220054 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -119,6 +119,15 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
 #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..d13bd221cd37 100644
--- a/arch/s390/include/asm/kexec.h
+++ b/arch/s390/include/asm/kexec.h
@@ -92,5 +92,8 @@ 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_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 c7c924e15011..5b6e2ae54906 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -193,6 +193,12 @@ 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 cf042d41c87b..f1e5327a7bf8 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 f7a4fd4d243f..620021679405 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -62,14 +62,7 @@ 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);
@@ -80,11 +73,6 @@ 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)
@@ -93,11 +81,6 @@ 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)
@@ -110,8 +93,7 @@ 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);
 }
@@ -616,19 +598,6 @@ 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


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