[tip: objtool/core] jump_label, x86: Factor out the __jump_table generation

From: tip-bot2 for Peter Zijlstra
Date: Wed May 12 2021 - 09:20:34 EST


The following commit has been merged into the objtool/core branch of tip:

Commit-ID: e1aa35c4c4bc71e44dabc9d7d167b807edd7b439
Gitweb: https://git.kernel.org/tip/e1aa35c4c4bc71e44dabc9d7d167b807edd7b439
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 06 May 2021 21:33:56 +02:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 12 May 2021 14:54:55 +02:00

jump_label, x86: Factor out the __jump_table generation

Both arch_static_branch() and arch_static_branch_jump() have the same
blurb to generate the __jump_table entry, share it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210506194157.663132781@xxxxxxxxxxxxx
---
arch/x86/include/asm/jump_label.h | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 01de21e..dfdc2b1 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -14,15 +14,19 @@
#include <linux/stringify.h>
#include <linux/types.h>

+#define JUMP_TABLE_ENTRY \
+ ".pushsection __jump_table, \"aw\" \n\t" \
+ _ASM_ALIGN "\n\t" \
+ ".long 1b - . \n\t" \
+ ".long %l[l_yes] - . \n\t" \
+ _ASM_PTR "%c0 + %c1 - .\n\t" \
+ ".popsection \n\t"
+
static __always_inline bool arch_static_branch(struct static_key * const key, const bool branch)
{
asm_volatile_goto("1:"
".byte " __stringify(BYTES_NOP5) "\n\t"
- ".pushsection __jump_table, \"aw\" \n\t"
- _ASM_ALIGN "\n\t"
- ".long 1b - ., %l[l_yes] - . \n\t"
- _ASM_PTR "%c0 + %c1 - .\n\t"
- ".popsection \n\t"
+ JUMP_TABLE_ENTRY
: : "i" (key), "i" (branch) : : l_yes);

return false;
@@ -33,13 +37,9 @@ l_yes:
static __always_inline bool arch_static_branch_jump(struct static_key * const key, const bool branch)
{
asm_volatile_goto("1:"
- ".byte 0xe9\n\t .long %l[l_yes] - 2f\n\t"
- "2:\n\t"
- ".pushsection __jump_table, \"aw\" \n\t"
- _ASM_ALIGN "\n\t"
- ".long 1b - ., %l[l_yes] - . \n\t"
- _ASM_PTR "%c0 + %c1 - .\n\t"
- ".popsection \n\t"
+ ".byte 0xe9 \n\t"
+ ".long %l[l_yes] - (. + 4) \n\t"
+ JUMP_TABLE_ENTRY
: : "i" (key), "i" (branch) : : l_yes);

return false;