Commit f4e3de75 authored by Heiko Carstens's avatar Heiko Carstens
Browse files

s390/fpu: provide and use lfpc, sfpc, and stfpc inline assemblies 



Instead of open-coding lfpc, sfpc, and stfpc inline assemblies at
several locations, provide an fpu_* function for each instruction and
use the function instead.

Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 88d8136a

arch/s390/include/asm/fpu-insn.h

+26 −0
Original line number Diff line number Diff line
@@ -45,6 +45,15 @@ static __always_inline void fpu_ld(unsigned short fpr, freg_t *reg) 
		     : "memory");

}



static __always_inline void fpu_lfpc(unsigned int *fpc)

{

	instrument_read(fpc, sizeof(*fpc));

	asm volatile("lfpc	%[fpc]"

		     :

		     : [fpc] "Q" (*fpc)

		     : "memory");

}



/**

 * fpu_lfpc_safe - Load floating point control register safely.

 * @fpc: new value for floating point control register
@@ -82,5 +91,22 @@ static __always_inline void fpu_std(unsigned short fpr, freg_t *reg) 
		     : "memory");

}



static __always_inline void fpu_sfpc(unsigned int fpc)

{

	asm volatile("sfpc	%[fpc]"

		     :

		     : [fpc] "d" (fpc)

		     : "memory");

}



static __always_inline void fpu_stfpc(unsigned int *fpc)

{

	instrument_write(fpc, sizeof(*fpc));

	asm volatile("stfpc	%[fpc]"

		     : [fpc] "=Q" (*fpc)

		     :

		     : "memory");

}



#endif /* __ASSEMBLY__ */

#endif	/* __ASM_S390_FPU_INSN_H */

arch/s390/kernel/fpu.c

+5 −9
Original line number Diff line number Diff line
@@ -17,10 +17,8 @@ void __kernel_fpu_begin(struct kernel_fpu *state, u32 flags) 
	 * in use by the previous context.

	 */

	flags &= state->mask;

	if (flags & KERNEL_FPC) {

		/* Save floating point control */

		asm volatile("stfpc %0" : "=Q" (state->fpc));

	}

	if (flags & KERNEL_FPC)

		fpu_stfpc(&state->fpc);

	if (!cpu_has_vx()) {

		if (flags & KERNEL_VXR_LOW)

			save_fp_regs(state->fprs);
@@ -80,10 +78,8 @@ void __kernel_fpu_end(struct kernel_fpu *state, u32 flags) 
	 * current context.

	 */

	flags &= state->mask;

	if (flags & KERNEL_FPC) {

		/* Restore floating-point controls */

		asm volatile("lfpc %0" : : "Q" (state->fpc));

	}

	if (flags & KERNEL_FPC)

		fpu_lfpc(&state->fpc);

	if (!cpu_has_vx()) {

		if (flags & KERNEL_VXR_LOW)

			load_fp_regs(state->fprs);
@@ -176,7 +172,7 @@ void save_fpu_regs(void) 
	state = &current->thread.fpu;

	regs = current->thread.fpu.regs;



	asm volatile("stfpc %0" : "=Q" (state->fpc));

	fpu_stfpc(&state->fpc);

	if (likely(cpu_has_vx())) {

		asm volatile("lgr	1,%0\n"

			     "VSTM	0,15,0,1\n"

arch/s390/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -191,7 +191,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) 
void execve_tail(void)

{

	current->thread.fpu.fpc = 0;

	asm volatile("sfpc %0" : : "d" (0));

	fpu_sfpc(0);

}



struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next)