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linux/arch/powerpc/include/asm/switch_to.h
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

117 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
*/
#ifndef _ASM_POWERPC_SWITCH_TO_H
#define _ASM_POWERPC_SWITCH_TO_H
#include <linux/sched.h>
#include <asm/reg.h>
struct thread_struct;
struct task_struct;
struct pt_regs;
extern struct task_struct *__switch_to(struct task_struct *,
struct task_struct *);
#define switch_to(prev, next, last) ((last) = __switch_to((prev), (next)))
extern struct task_struct *_switch(struct thread_struct *prev,
struct thread_struct *next);
extern void switch_booke_debug_regs(struct debug_reg *new_debug);
extern int emulate_altivec(struct pt_regs *);
#ifdef CONFIG_PPC_BOOK3S_64
void restore_math(struct pt_regs *regs);
#else
static inline void restore_math(struct pt_regs *regs)
{
}
#endif
void restore_tm_state(struct pt_regs *regs);
extern void flush_all_to_thread(struct task_struct *);
extern void giveup_all(struct task_struct *);
#ifdef CONFIG_PPC_FPU
extern void enable_kernel_fp(void);
extern void flush_fp_to_thread(struct task_struct *);
extern void giveup_fpu(struct task_struct *);
extern void save_fpu(struct task_struct *);
static inline void disable_kernel_fp(void)
{
msr_check_and_clear(MSR_FP);
}
#else
static inline void save_fpu(struct task_struct *t) { }
static inline void flush_fp_to_thread(struct task_struct *t) { }
#endif
#ifdef CONFIG_ALTIVEC
extern void enable_kernel_altivec(void);
extern void flush_altivec_to_thread(struct task_struct *);
extern void giveup_altivec(struct task_struct *);
extern void save_altivec(struct task_struct *);
static inline void disable_kernel_altivec(void)
{
msr_check_and_clear(MSR_VEC);
}
#else
static inline void save_altivec(struct task_struct *t) { }
static inline void __giveup_altivec(struct task_struct *t) { }
#endif
#ifdef CONFIG_VSX
extern void enable_kernel_vsx(void);
extern void flush_vsx_to_thread(struct task_struct *);
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
#ifdef CONFIG_SPE
extern void enable_kernel_spe(void);
extern void flush_spe_to_thread(struct task_struct *);
extern void giveup_spe(struct task_struct *);
extern void __giveup_spe(struct task_struct *);
static inline void disable_kernel_spe(void)
{
msr_check_and_clear(MSR_SPE);
}
#else
static inline void __giveup_spe(struct task_struct *t) { }
#endif
static inline void clear_task_ebb(struct task_struct *t)
{
#ifdef CONFIG_PPC_BOOK3S_64
/* EBB perf events are not inherited, so clear all EBB state. */
t->thread.ebbrr = 0;
t->thread.ebbhr = 0;
t->thread.bescr = 0;
t->thread.mmcr2 = 0;
t->thread.mmcr0 = 0;
t->thread.siar = 0;
t->thread.sdar = 0;
t->thread.sier = 0;
t->thread.used_ebb = 0;
#endif
}
extern int set_thread_tidr(struct task_struct *t);
#endif /* _ASM_POWERPC_SWITCH_TO_H */