In preparation for the objtool klp diff subcommand, define the entry
size for the discard.unwind_hints section in its ELF header. This will
allow tooling to extract individual entries.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/kernel/unwind_orc.c | 2 ++
include/linux/objtool.h | 9 ++++++---
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 977ee75e047c..4624d6d916a2 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -199,6 +199,8 @@ static struct orc_entry *orc_find(unsigned long ip)
{
static struct orc_entry *orc;
+ BUILD_BUG_ON(UNWIND_HINT_SIZE != sizeof(struct unwind_hint));
+
if (ip == 0)
return &null_orc_entry;
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 366ad004d794..483dd3131826 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -8,11 +8,14 @@
#include <asm/asm.h>
+#define UNWIND_HINT_SIZE 12
+
#ifndef __ASSEMBLY__
-#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
"987: \n\t" \
- ".pushsection .discard.unwind_hints\n\t" \
+ ".pushsection .discard.unwind_hints, \"M\", @progbits, "\
+ __stringify(UNWIND_HINT_SIZE) "\n\t" \
/* struct unwind_hint */ \
".long 987b - .\n\t" \
".short " __stringify(sp_offset) "\n\t" \
@@ -88,7 +91,7 @@
*/
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.Lhere_\@:
- .pushsection .discard.unwind_hints
+ .pushsection .discard.unwind_hints, "M", @progbits, UNWIND_HINT_SIZE
/* struct unwind_hint */
.long .Lhere_\@ - .
.short \sp_offset
--
2.49.0