When compiling an external kernel module with `-O0` or `-O1`, the following
compile error may be reported:
./arch/x86/include/asm/jump_label.h:25:2: error: impossible constraint in
‘asm’
25 | asm_volatile_goto("1:"
| ^~~~~~~~~~~~~~~~~
It appears that these lower optimization levels prevent GCC from detecting
that the key/branch arguments can be treated as constants and used as
immediate operands. To work around this, explicitly add the `const` label.
Signed-off-by: Jason Gerecke <jason.gere...@wacom.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Ard Biesheuvel <a...@kernel.org>
---
Marked RFC since I'm not familiar with this subsystem or the asm blocks that
are impacted. Extra-close inspection would be appreciated.
arch/x86/include/asm/jump_label.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/jump_label.h
b/arch/x86/include/asm/jump_label.h
index 06c3cc22a058..7f2006645d84 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -20,7 +20,7 @@
#include <linux/stringify.h>
#include <linux/types.h>
-static __always_inline bool arch_static_branch(struct static_key *key, bool
branch)
+static __always_inline bool arch_static_branch(struct static_key * const key,
const bool branch)
{
asm_volatile_goto("1:"
".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
@@ -36,7 +36,7 @@ static __always_inline bool arch_static_branch(struct
static_key *key, bool bran
return true;
}
-static __always_inline bool arch_static_branch_jump(struct static_key *key,
bool branch)
+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"
--
2.30.1
