linux/arch/powerpc
Christophe Leroy bd73758803 powerpc: Fix missing declaration of [en/dis]able_kernel_vsx()
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: 16a9dea110 ("amdgpu: Enable initial DCN support on POWER")
Cc: stable@vger.kernel.org # v5.6+
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Incorporate some discussion comments into the change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8d7d285a027e9d21f5ff7f850fa71a2655b0c4af.1615279170.git.christophe.leroy@csgroup.eu
2021-03-10 11:15:00 +11:00
..
boot powerpc/boot: Fix build of dts/fsl 2020-12-21 22:06:09 +11:00
configs Modules updates for v5.12 2021-02-23 10:15:33 -08:00
crypto crypto: powerpc/sha256 - remove unneeded semicolon 2021-02-10 17:55:57 +11:00
include powerpc: Fix missing declaration of [en/dis]able_kernel_vsx() 2021-03-10 11:15:00 +11:00
kernel powerpc/64s/exception: Clean up a missed SRR specifier 2021-03-10 07:59:31 +11:00
kexec powerpc/kexec_file: fix FDT size estimation for kdump kernel 2021-02-11 23:35:07 +11:00
kvm x86: 2021-02-26 10:00:12 -08:00
lib powerpc/sstep: Fix VSX instruction emulation 2021-03-02 22:41:51 +11:00
math-emu
mm powerpc updates for 5.12 2021-02-22 14:34:00 -08:00
net bpf: Rename BPF_XADD and prepare to encode other atomics in .imm 2021-01-14 18:34:29 -08:00
perf powerpc/perf: Fix handling of privilege level checks in perf interrupt context 2021-03-02 22:41:51 +11:00
platforms vio: make remove callback return void 2021-03-02 22:41:23 +11:00
purgatory powerpc/kexec_file: Enable early kernel OPAL calls 2020-07-29 23:47:55 +10:00
sysdev powerpc/xive: Improve error reporting of OPAL calls 2020-12-11 09:53:11 +11:00
tools powerpc/tools: Remove 90 line limit in checkpatch script 2020-09-08 22:57:11 +10:00
xmon powerpc/32s: mfsrin()/mtsrin() become mfsr()/mtsr() 2021-02-09 01:10:15 +11:00
Kbuild powerpc/kexec: Move kexec files into a dedicated subdir. 2019-11-21 15:41:34 +11:00
Kconfig Rework of the X86 irq stack handling: 2021-02-24 16:32:23 -08:00
Kconfig.debug powerpc/xmon: Select CONSOLE_POLL for the 8xx 2021-01-31 22:35:51 +11:00
Makefile Kbuild updates for v5.12 2021-02-25 10:17:31 -08:00
Makefile.postlink powerpc: unrel_branch_check.sh: use nm to find symbol value 2020-09-02 11:00:22 +10:00