From 864b435514b286c0be2a38a02f487aa28d990ef8 Mon Sep 17 00:00:00 2001 From: Jason Gerecke Date: Thu, 11 Feb 2021 13:48:48 -0800 Subject: x86/jump_label: Mark arguments as const to satisfy asm constraints MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Steven Rostedt (VMware) Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20210211214848.536626-1-jason.gerecke@wacom.com --- arch/x86/include/asm/jump_label.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch') 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 #include -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" -- cgit v1.2.3