Le 09/03/2021 à 09:45, Geert Uytterhoeven a écrit :
Hi Christophe,
On Tue, Mar 9, 2021 at 9:39 AM Christophe Leroy
<christophe.leroy@xxxxxxxxxx> wrote:
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
Fixes: 16a9dea110a6 ("amdgpu: Enable initial DCN support on POWER")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Thanks for your patch!
--- 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(void)
{
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
I'm wondering how this is any better than the current situation: using
BUILD_BUG() will still cause a build failure?
No it won't cause a failure. In drivers/gpu/drm/amd/display/dc/os_types.h you have:
#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.
What about adding "depends on !POWERPC || VSX" instead, to prevent
the issue from happening in the first place?
CONFIG_VSX is not required as pointed by the DC_FP_START() macro above and the matching DC_FP_END()
macro.
Gr{oetje,eeting}s,
Geert
Christophe
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