6.12-stable review patch. If anyone has any objections, please let me know.
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From: Mark Rutland mark.rutland@arm.com
[ Upstream commit f699c66691fb7e08a5a631c5baf5f2a19b7a6468 ]
Historically fpsimd_to_sve() and sve_to_fpsimd() were (conditionally) called by functions which were defined regardless of CONFIG_ARM64_SVE. Hence it was necessary that both fpsimd_to_sve() and sve_to_fpsimd() were always defined and not guarded by ifdeffery.
As a result of the removal of fpsimd_signal_preserve_current_state() in commit:
929fa99b1215966f ("arm64/fpsimd: signal: Always save+flush state early")
... sve_to_fpsimd() has no callers when CONFIG_ARM64_SVE=n, resulting in a build-time warnign that it is unused:
| arch/arm64/kernel/fpsimd.c:676:13: warning: unused function 'sve_to_fpsimd' [-Wunused-function] | 676 | static void sve_to_fpsimd(struct task_struct *task) | | ^~~~~~~~~~~~~ | 1 warning generated.
In contrast, fpsimd_to_sve() still has callers which are defined when CONFIG_ARM64_SVE=n, and it would be awkward to hide this behind ifdeffery and/or to use stub functions.
For now, suppress the warning by marking both fpsimd_to_sve() and sve_to_fpsimd() as 'static inline', as we usually do for stub functions. The compiler will no longer warn if either function is unused.
Aside from suppressing the warning, there should be no functional change as a result of this patch.
Link: https://lore.kernel.org/linux-arm-kernel/20250429194600.GA26883@willie-the-t... Reported-by: Will Deacon will@kernel.org Fixes: 929fa99b1215 ("arm64/fpsimd: signal: Always save+flush state early") Signed-off-by: Mark Rutland mark.rutland@arm.com Cc: Marc Zyngier maz@kernel.org Cc: Mark Brown broonie@kernel.org Cc: Will Deacon will@kernel.org Link: https://lore.kernel.org/r/20250430173240.4023627-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/kernel/fpsimd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 9f4f3d54c2207..c5285ee55bfb0 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -651,7 +651,7 @@ static void __fpsimd_to_sve(void *sst, struct user_fpsimd_state const *fst, * task->thread.uw.fpsimd_state must be up to date before calling this * function. */ -static void fpsimd_to_sve(struct task_struct *task) +static inline void fpsimd_to_sve(struct task_struct *task) { unsigned int vq; void *sst = task->thread.sve_state; @@ -675,7 +675,7 @@ static void fpsimd_to_sve(struct task_struct *task) * bytes of allocated kernel memory. * task->thread.sve_state must be up to date before calling this function. */ -static void sve_to_fpsimd(struct task_struct *task) +static inline void sve_to_fpsimd(struct task_struct *task) { unsigned int vq, vl; void const *sst = task->thread.sve_state;