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| author | Jason Gerecke <killertofu@gmail.com> | 2021-02-12 00:48:48 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-03-06 14:51:00 +0300 |
| commit | 864b435514b286c0be2a38a02f487aa28d990ef8 (patch) | |
| tree | bb74bf3a26e61bb8e80ff0b2df5129aefc16d7ab /arch/x86/include/asm/jump_label.h | |
| parent | a5aabace5fb8abf2adcfcf0fe54c089b20d71755 (diff) | |
| download | linux-864b435514b286c0be2a38a02f487aa28d990ef8.tar.xz | |
x86/jump_label: Mark arguments as const to satisfy asm constraints
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.gerecke@wacom.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20210211214848.536626-1-jason.gerecke@wacom.com
Diffstat (limited to 'arch/x86/include/asm/jump_label.h')
| -rw-r--r-- | arch/x86/include/asm/jump_label.h | 4 |
1 files 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 @@ l_yes: 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" |