This is a note to let you know that I've just added the patch titled powerpc: Fix missing declaration of [en/dis]able_kernel_vsx() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-fix-missing-declaration-of-able_kernel_vsx.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From bd73758803c2eedc037c2268b65a19542a832594 Mon Sep 17 00:00:00 2001 From: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Date: Tue, 9 Mar 2021 08:39:39 +0000 Subject: powerpc: Fix missing declaration of [en/dis]able_kernel_vsx() From: Christophe Leroy <christophe.leroy@xxxxxxxxxx> commit bd73758803c2eedc037c2268b65a19542a832594 upstream. Add stub instances of enable_kernel_vsx() and disable_kernel_vsx() when CONFIG_VSX is not set, to avoid following build failure. CC [M] drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dcn_calcs.o In file included from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dm_services_types.h:29, from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dm_services.h:37, from drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dcn_calcs.c:27: drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dcn_calcs.c: In function 'dcn_bw_apply_registry_override': ./drivers/gpu/drm/amd/amdgpu/../display/dc/os_types.h:64:3: error: implicit declaration of function 'enable_kernel_vsx'; did you mean 'enable_kernel_fp'? [-Werror=implicit-function-declaration] 64 | enable_kernel_vsx(); \ | ^~~~~~~~~~~~~~~~~ drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dcn_calcs.c:640:2: note: in expansion of macro 'DC_FP_START' 640 | DC_FP_START(); | ^~~~~~~~~~~ ./drivers/gpu/drm/amd/amdgpu/../display/dc/os_types.h:75:3: error: implicit declaration of function 'disable_kernel_vsx'; did you mean 'disable_kernel_fp'? [-Werror=implicit-function-declaration] 75 | disable_kernel_vsx(); \ | ^~~~~~~~~~~~~~~~~~ drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dcn_calcs.c:676:2: note: in expansion of macro 'DC_FP_END' 676 | DC_FP_END(); | ^~~~~~~~~ cc1: some warnings being treated as errors make[5]: *** [drivers/gpu/drm/amd/amdgpu/../display/dc/calcs/dcn_calcs.o] Error 1 This works because the caller is checking if VSX is available using cpu_has_feature(): #define DC_FP_START() { \ if (cpu_has_feature(CPU_FTR_VSX_COMP)) { \ preempt_disable(); \ enable_kernel_vsx(); \ } else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP)) { \ preempt_disable(); \ enable_kernel_altivec(); \ } else if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE)) { \ preempt_disable(); \ enable_kernel_fp(); \ } \ When CONFIG_VSX is not selected, cpu_has_feature(CPU_FTR_VSX_COMP) constant folds to 'false' so the call to enable_kernel_vsx() is discarded and the build succeeds. Fixes: 16a9dea110a6 ("amdgpu: Enable initial DCN support on POWER") Cc: stable@xxxxxxxxxxxxxxx # v5.6+ Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> [mpe: Incorporate some discussion comments into the change log] Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/8d7d285a027e9d21f5ff7f850fa71a2655b0c4af.1615279170.git.christophe.leroy@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/include/asm/switch_to.h | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -71,6 +71,16 @@ static inline void disable_kernel_vsx(vo { msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX); } +#else +static inline void enable_kernel_vsx(void) +{ + BUILD_BUG(); +} + +static inline void disable_kernel_vsx(void) +{ + BUILD_BUG(); +} #endif #ifdef CONFIG_SPE Patches currently in stable-queue which might be from christophe.leroy@xxxxxxxxxx are queue-5.10/powerpc-fix-missing-declaration-of-able_kernel_vsx.patch queue-5.10/powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch