In preparation for the objtool klp diff subcommand, define the entry
size for the .altinstructions section in its ELF header. This will
allow tooling to extract individual entries.
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org>
---
arch/um/include/shared/common-offsets.h | 2 ++
arch/x86/include/asm/alternative.h | 5 +++--
arch/x86/include/asm/asm.h | 4 ++++
arch/x86/kernel/asm-offsets.c | 2 ++
arch/x86/um/shared/sysdep/kernel-offsets.h | 1 +
kernel/bounds.c | 1 +
scripts/mod/devicetable-offsets.c | 1 +
7 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/um/include/shared/common-offsets.h
b/arch/um/include/shared/common-offsets.h
index 8ca66a1918c3..4e19103afd71 100644
--- a/arch/um/include/shared/common-offsets.h
+++ b/arch/um/include/shared/common-offsets.h
@@ -18,3 +18,5 @@ DEFINE(UM_NSEC_PER_USEC, NSEC_PER_USEC);
DEFINE(UM_KERN_GDT_ENTRY_TLS_ENTRIES, GDT_ENTRY_TLS_ENTRIES);
DEFINE(UM_SECCOMP_ARCH_NATIVE, SECCOMP_ARCH_NATIVE);
+
+DEFINE(ALT_INSTR_SIZE, sizeof(struct alt_instr));
diff --git a/arch/x86/include/asm/alternative.h
b/arch/x86/include/asm/alternative.h
index 15bc07a5ebb3..eb24d9ba30d7 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -197,7 +197,8 @@ static inline int alternatives_text_reserved(void *start,
void *end)
"773:\n"
#define ALTINSTR_ENTRY(ft_flags) \
- ".pushsection .altinstructions,\"a\"\n" \
+ ".pushsection .altinstructions, \"aM\", @progbits, " \
+ __stringify(ALT_INSTR_SIZE) "\n" \
" .long 771b - .\n" /* label */ \
" .long 774f - .\n" /* new instruction */ \
" .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
@@ -360,7 +361,7 @@ void nop_func(void);
741: \
.skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90
;\
742: \
- .pushsection .altinstructions,"a" ; \
+ .pushsection .altinstructions, "aM", @progbits, ALT_INSTR_SIZE ;\
altinstr_entry 740b,743f,flag,742b-740b,744f-743f ; \
.popsection ; \
.pushsection .altinstr_replacement,"ax" ; \
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index f963848024a5..1f26f90a57ce 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -136,6 +136,10 @@ static __always_inline __pure void *rip_rel_ptr(void *p)
#ifdef __KERNEL__
+#ifndef COMPILE_OFFSETS
+#include <asm/asm-offsets.h>
+#endif
+
# include <asm/extable_fixup_types.h>
/* Exception table entry */
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 6259b474073b..b51625c3f64c 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -123,4 +123,6 @@ static void __used common(void)
OFFSET(ARIA_CTX_rounds, aria_ctx, rounds);
#endif
+ BLANK();
+ DEFINE(ALT_INSTR_SIZE, sizeof(struct alt_instr));
}
diff --git a/arch/x86/um/shared/sysdep/kernel-offsets.h
b/arch/x86/um/shared/sysdep/kernel-offsets.h
index 6fd1ed400399..9f6d3d1a248c 100644
--- a/arch/x86/um/shared/sysdep/kernel-offsets.h
+++ b/arch/x86/um/shared/sysdep/kernel-offsets.h
@@ -1,4 +1,5 @@
/* SPDX-License-Identifier: GPL-2.0 */
+#define COMPILE_OFFSETS
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/elf.h>
diff --git a/kernel/bounds.c b/kernel/bounds.c
index 29b2cd00df2c..02b619eb6106 100644
--- a/kernel/bounds.c
+++ b/kernel/bounds.c
@@ -6,6 +6,7 @@
*/
#define __GENERATING_BOUNDS_H
+#define COMPILE_OFFSETS
/* Include headers that define the enum constants of interest */
#include <linux/page-flags.h>
#include <linux/mmzone.h>
diff --git a/scripts/mod/devicetable-offsets.c
b/scripts/mod/devicetable-offsets.c
index d3d00e85edf7..ef2ffb68f69d 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
+#define COMPILE_OFFSETS
#include <linux/kbuild.h>
#include <linux/mod_devicetable.h>
--
2.49.0
