arch/s390/include/asm/fpu.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * In-kernel FPU support functions
  *
  *
  * Consider these guidelines before using in-kernel FPU functions:
  *
  *  1. Use kernel_fpu_begin() and kernel_fpu_end() to enclose all in-kernel
  *     use of floating-point or vector registers and instructions.
  *
  *  2. For kernel_fpu_begin(), specify the vector register range you want to
  *     use with the KERNEL_VXR_* constants. Consider these usage guidelines:
  *
  *     a) If your function typically runs in process-context, use the lower
  *	  half of the vector registers, for example, specify KERNEL_VXR_LOW.
  *     b) If your function typically runs in soft-irq or hard-irq context,
  *	  prefer using the upper half of the vector registers, for example,
  *	  specify KERNEL_VXR_HIGH.
  *
  *     If you adhere to these guidelines, an interrupted process context
  *     does not require to save and restore vector registers because of
  *     disjoint register ranges.
  *
  *     Also note that the __kernel_fpu_begin()/__kernel_fpu_end() functions
  *     includes logic to save and restore up to 16 vector registers at once.
  *
  *  3. You can nest kernel_fpu_begin()/kernel_fpu_end() by using different
  *     struct kernel_fpu states.  Vector registers that are in use by outer
  *     levels are saved and restored.  You can minimize the save and restore
  *     effort by choosing disjoint vector register ranges.
  *
  *  5. To use vector floating-point instructions, specify the KERNEL_FPC
  *     flag to save and restore floating-point controls in addition to any
  *     vector register range.
  *
  *  6. To use floating-point registers and instructions only, specify the
  *     KERNEL_FPR flag.  This flag triggers a save and restore of vector
  *     registers V0 to V15 and floating-point controls.
  *
  * Copyright IBM Corp. 2015
  * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  */

 #ifndef _ASM_S390_FPU_H
 #define _ASM_S390_FPU_H

 #include <linux/processor.h>
 #include <linux/preempt.h>
 #include <linux/string.h>
 #include <linux/sched.h>
 #include <asm/sigcontext.h>
 #include <asm/fpu-types.h>
 #include <asm/fpu-insn.h>
 #include <asm/facility.h>

 static inline bool cpu_has_vx(void)
 {
 	return likely(test_facility(129));
 }

 enum {
 	KERNEL_FPC_BIT = 0,
 	KERNEL_VXR_V0V7_BIT,
 	KERNEL_VXR_V8V15_BIT,
 	KERNEL_VXR_V16V23_BIT,
 	KERNEL_VXR_V24V31_BIT,
 };

 #define KERNEL_FPC		BIT(KERNEL_FPC_BIT)
 #define KERNEL_VXR_V0V7		BIT(KERNEL_VXR_V0V7_BIT)
 #define KERNEL_VXR_V8V15	BIT(KERNEL_VXR_V8V15_BIT)
 #define KERNEL_VXR_V16V23	BIT(KERNEL_VXR_V16V23_BIT)
 #define KERNEL_VXR_V24V31	BIT(KERNEL_VXR_V24V31_BIT)

 #define KERNEL_VXR_LOW		(KERNEL_VXR_V0V7   | KERNEL_VXR_V8V15)
 #define KERNEL_VXR_MID		(KERNEL_VXR_V8V15  | KERNEL_VXR_V16V23)
 #define KERNEL_VXR_HIGH		(KERNEL_VXR_V16V23 | KERNEL_VXR_V24V31)

 #define KERNEL_VXR		(KERNEL_VXR_LOW	   | KERNEL_VXR_HIGH)
 #define KERNEL_FPR		(KERNEL_FPC	   | KERNEL_VXR_LOW)

 void load_fpu_state(struct fpu *state, int flags);
 void save_fpu_state(struct fpu *state, int flags);
 void __kernel_fpu_begin(struct kernel_fpu *state, int flags);
 void __kernel_fpu_end(struct kernel_fpu *state, int flags);

 static __always_inline void save_vx_regs(__vector128 *vxrs)
 {
 	fpu_vstm(0, 15, &vxrs[0]);
 	fpu_vstm(16, 31, &vxrs[16]);
 }

 static __always_inline void load_vx_regs(__vector128 *vxrs)
 {
 	fpu_vlm(0, 15, &vxrs[0]);
 	fpu_vlm(16, 31, &vxrs[16]);
 }

 static __always_inline void __save_fp_regs(freg_t *fprs, unsigned int offset)
 {
 	fpu_std(0, &fprs[0 * offset]);
 	fpu_std(1, &fprs[1 * offset]);
 	fpu_std(2, &fprs[2 * offset]);
 	fpu_std(3, &fprs[3 * offset]);
 	fpu_std(4, &fprs[4 * offset]);
 	fpu_std(5, &fprs[5 * offset]);
 	fpu_std(6, &fprs[6 * offset]);
 	fpu_std(7, &fprs[7 * offset]);
 	fpu_std(8, &fprs[8 * offset]);
 	fpu_std(9, &fprs[9 * offset]);
 	fpu_std(10, &fprs[10 * offset]);
 	fpu_std(11, &fprs[11 * offset]);
 	fpu_std(12, &fprs[12 * offset]);
 	fpu_std(13, &fprs[13 * offset]);
 	fpu_std(14, &fprs[14 * offset]);
 	fpu_std(15, &fprs[15 * offset]);
 }

 static __always_inline void __load_fp_regs(freg_t *fprs, unsigned int offset)
 {
 	fpu_ld(0, &fprs[0 * offset]);
 	fpu_ld(1, &fprs[1 * offset]);
 	fpu_ld(2, &fprs[2 * offset]);
 	fpu_ld(3, &fprs[3 * offset]);
 	fpu_ld(4, &fprs[4 * offset]);
 	fpu_ld(5, &fprs[5 * offset]);
 	fpu_ld(6, &fprs[6 * offset]);
 	fpu_ld(7, &fprs[7 * offset]);
 	fpu_ld(8, &fprs[8 * offset]);
 	fpu_ld(9, &fprs[9 * offset]);
 	fpu_ld(10, &fprs[10 * offset]);
 	fpu_ld(11, &fprs[11 * offset]);
 	fpu_ld(12, &fprs[12 * offset]);
 	fpu_ld(13, &fprs[13 * offset]);
 	fpu_ld(14, &fprs[14 * offset]);
 	fpu_ld(15, &fprs[15 * offset]);
 }

 static __always_inline void save_fp_regs(freg_t *fprs)
 {
 	__save_fp_regs(fprs, sizeof(freg_t) / sizeof(freg_t));
 }

 static __always_inline void load_fp_regs(freg_t *fprs)
 {
 	__load_fp_regs(fprs, sizeof(freg_t) / sizeof(freg_t));
 }

 static __always_inline void save_fp_regs_vx(__vector128 *vxrs)
 {
 	freg_t *fprs = (freg_t *)&vxrs[0].high;

 	__save_fp_regs(fprs, sizeof(__vector128) / sizeof(freg_t));
 }

 static __always_inline void load_fp_regs_vx(__vector128 *vxrs)
 {
 	freg_t *fprs = (freg_t *)&vxrs[0].high;

 	__load_fp_regs(fprs, sizeof(__vector128) / sizeof(freg_t));
 }

 static inline void load_user_fpu_regs(void)
 {
 	struct thread_struct *thread = &current->thread;

 	if (!thread->ufpu_flags)
 		return;
 	load_fpu_state(&thread->ufpu, thread->ufpu_flags);
 	thread->ufpu_flags = 0;
 }

 static __always_inline void __save_user_fpu_regs(struct thread_struct *thread, int flags)
 {
 	save_fpu_state(&thread->ufpu, flags);
 	__atomic_or(flags, &thread->ufpu_flags);
 }

 static inline void save_user_fpu_regs(void)
 {
 	struct thread_struct *thread = &current->thread;
 	int mask, flags;

 	mask = __atomic_or(KERNEL_FPC | KERNEL_VXR, &thread->kfpu_flags);
 	flags = ~READ_ONCE(thread->ufpu_flags) & (KERNEL_FPC | KERNEL_VXR);
 	if (flags)
 		__save_user_fpu_regs(thread, flags);
 	barrier();
 	WRITE_ONCE(thread->kfpu_flags, mask);
 }

 static __always_inline void _kernel_fpu_begin(struct kernel_fpu *state, int flags)
 {
 	struct thread_struct *thread = &current->thread;
 	int mask, uflags;

 	mask = __atomic_or(flags, &thread->kfpu_flags);
 	state->hdr.mask = mask;
 	uflags = READ_ONCE(thread->ufpu_flags);
 	if ((uflags & flags) != flags)
 		__save_user_fpu_regs(thread, ~uflags & flags);
 	if (mask & flags)
 		__kernel_fpu_begin(state, flags);
 }

 static __always_inline void _kernel_fpu_end(struct kernel_fpu *state, int flags)
 {
 	int mask = state->hdr.mask;

 	if (mask & flags)
 		__kernel_fpu_end(state, flags);
 	barrier();
 	WRITE_ONCE(current->thread.kfpu_flags, mask);
 }

 void __kernel_fpu_invalid_size(void);

 static __always_inline void kernel_fpu_check_size(int flags, unsigned int size)
 {
 	unsigned int cnt = 0;

 	if (flags & KERNEL_VXR_V0V7)
 		cnt += 8;
 	if (flags & KERNEL_VXR_V8V15)
 		cnt += 8;
 	if (flags & KERNEL_VXR_V16V23)
 		cnt += 8;
 	if (flags & KERNEL_VXR_V24V31)
 		cnt += 8;
 	if (cnt != size)
 		__kernel_fpu_invalid_size();
 }

 #define kernel_fpu_begin(state, flags)					\
 {									\
 	typeof(state) s = (state);					\
 	int _flags = (flags);						\
 									\
 	kernel_fpu_check_size(_flags, ARRAY_SIZE(s->vxrs));		\
 	_kernel_fpu_begin((struct kernel_fpu *)s, _flags);		\
 }

 #define kernel_fpu_end(state, flags)					\
 {									\
 	typeof(state) s = (state);					\
 	int _flags = (flags);						\
 									\
 	kernel_fpu_check_size(_flags, ARRAY_SIZE(s->vxrs));		\
 	_kernel_fpu_end((struct kernel_fpu *)s, _flags);		\
 }

 static inline void save_kernel_fpu_regs(struct thread_struct *thread)
 {
 	if (!thread->kfpu_flags)
 		return;
 	save_fpu_state(&thread->kfpu, thread->kfpu_flags);
 }

 static inline void restore_kernel_fpu_regs(struct thread_struct *thread)
 {
 	if (!thread->kfpu_flags)
 		return;
 	load_fpu_state(&thread->kfpu, thread->kfpu_flags);
 }

 static inline void convert_vx_to_fp(freg_t *fprs, __vector128 *vxrs)
 {
 	int i;

 	for (i = 0; i < __NUM_FPRS; i++)
 		fprs[i].ui = vxrs[i].high;
 }

 static inline void convert_fp_to_vx(__vector128 *vxrs, freg_t *fprs)
 {
 	int i;

 	for (i = 0; i < __NUM_FPRS; i++)
 		vxrs[i].high = fprs[i].ui;
 }

 static inline void fpregs_store(_s390_fp_regs *fpregs, struct fpu *fpu)
 {
 	fpregs->pad = 0;
 	fpregs->fpc = fpu->fpc;
 	convert_vx_to_fp((freg_t *)&fpregs->fprs, fpu->vxrs);
 }

 static inline void fpregs_load(_s390_fp_regs *fpregs, struct fpu *fpu)
 {
 	fpu->fpc = fpregs->fpc;
 	convert_fp_to_vx(fpu->vxrs, (freg_t *)&fpregs->fprs);
 }

 #endif /* _ASM_S390_FPU_H */
	/* SPDX-License-Identifier: GPL-2.0 */
	/*
	* In-kernel FPU support functions
	*
	*
	* Consider these guidelines before using in-kernel FPU functions:
	*
	* 1. Use kernel_fpu_begin() and kernel_fpu_end() to enclose all in-kernel
	* use of floating-point or vector registers and instructions.
	*
	* 2. For kernel_fpu_begin(), specify the vector register range you want to
	* use with the KERNEL_VXR_* constants. Consider these usage guidelines:
	*
	* a) If your function typically runs in process-context, use the lower
	* half of the vector registers, for example, specify KERNEL_VXR_LOW.
	* b) If your function typically runs in soft-irq or hard-irq context,
	* prefer using the upper half of the vector registers, for example,
	* specify KERNEL_VXR_HIGH.
	*
	* If you adhere to these guidelines, an interrupted process context
	* does not require to save and restore vector registers because of
	* disjoint register ranges.
	*
	* Also note that the __kernel_fpu_begin()/__kernel_fpu_end() functions
	* includes logic to save and restore up to 16 vector registers at once.
	*
	* 3. You can nest kernel_fpu_begin()/kernel_fpu_end() by using different
	* struct kernel_fpu states. Vector registers that are in use by outer
	* levels are saved and restored. You can minimize the save and restore
	* effort by choosing disjoint vector register ranges.
	*
	* 5. To use vector floating-point instructions, specify the KERNEL_FPC
	* flag to save and restore floating-point controls in addition to any
	* vector register range.
	*
	* 6. To use floating-point registers and instructions only, specify the
	* KERNEL_FPR flag. This flag triggers a save and restore of vector
	* registers V0 to V15 and floating-point controls.
	*
	* Copyright IBM Corp. 2015
	* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
	*/

	#ifndef _ASM_S390_FPU_H
	#define _ASM_S390_FPU_H

	#include <linux/processor.h>
	#include <linux/preempt.h>
	#include <linux/string.h>
	#include <linux/sched.h>
	#include <asm/sigcontext.h>
	#include <asm/fpu-types.h>
	#include <asm/fpu-insn.h>
	#include <asm/facility.h>

	static inline bool cpu_has_vx(void)
	{
	return likely(test_facility(129));
	}

	enum {
	KERNEL_FPC_BIT = 0,
	KERNEL_VXR_V0V7_BIT,
	KERNEL_VXR_V8V15_BIT,
	KERNEL_VXR_V16V23_BIT,
	KERNEL_VXR_V24V31_BIT,
	};

	#define KERNEL_FPC BIT(KERNEL_FPC_BIT)
	#define KERNEL_VXR_V0V7 BIT(KERNEL_VXR_V0V7_BIT)
	#define KERNEL_VXR_V8V15 BIT(KERNEL_VXR_V8V15_BIT)
	#define KERNEL_VXR_V16V23 BIT(KERNEL_VXR_V16V23_BIT)
	#define KERNEL_VXR_V24V31 BIT(KERNEL_VXR_V24V31_BIT)

	#define KERNEL_VXR_LOW (KERNEL_VXR_V0V7 \| KERNEL_VXR_V8V15)
	#define KERNEL_VXR_MID (KERNEL_VXR_V8V15 \| KERNEL_VXR_V16V23)
	#define KERNEL_VXR_HIGH (KERNEL_VXR_V16V23 \| KERNEL_VXR_V24V31)

	#define KERNEL_VXR (KERNEL_VXR_LOW \| KERNEL_VXR_HIGH)
	#define KERNEL_FPR (KERNEL_FPC \| KERNEL_VXR_LOW)

	void load_fpu_state(struct fpu *state, int flags);
	void save_fpu_state(struct fpu *state, int flags);
	void __kernel_fpu_begin(struct kernel_fpu *state, int flags);
	void __kernel_fpu_end(struct kernel_fpu *state, int flags);

	static __always_inline void save_vx_regs(__vector128 *vxrs)
	{
	fpu_vstm(0, 15, &vxrs[0]);
	fpu_vstm(16, 31, &vxrs[16]);
	}

	static __always_inline void load_vx_regs(__vector128 *vxrs)
	{
	fpu_vlm(0, 15, &vxrs[0]);
	fpu_vlm(16, 31, &vxrs[16]);
	}

	static __always_inline void __save_fp_regs(freg_t *fprs, unsigned int offset)
	{
	fpu_std(0, &fprs[0 * offset]);
	fpu_std(1, &fprs[1 * offset]);
	fpu_std(2, &fprs[2 * offset]);
	fpu_std(3, &fprs[3 * offset]);
	fpu_std(4, &fprs[4 * offset]);
	fpu_std(5, &fprs[5 * offset]);
	fpu_std(6, &fprs[6 * offset]);
	fpu_std(7, &fprs[7 * offset]);
	fpu_std(8, &fprs[8 * offset]);
	fpu_std(9, &fprs[9 * offset]);
	fpu_std(10, &fprs[10 * offset]);
	fpu_std(11, &fprs[11 * offset]);
	fpu_std(12, &fprs[12 * offset]);
	fpu_std(13, &fprs[13 * offset]);
	fpu_std(14, &fprs[14 * offset]);
	fpu_std(15, &fprs[15 * offset]);
	}

	static __always_inline void __load_fp_regs(freg_t *fprs, unsigned int offset)
	{
	fpu_ld(0, &fprs[0 * offset]);
	fpu_ld(1, &fprs[1 * offset]);
	fpu_ld(2, &fprs[2 * offset]);
	fpu_ld(3, &fprs[3 * offset]);
	fpu_ld(4, &fprs[4 * offset]);
	fpu_ld(5, &fprs[5 * offset]);
	fpu_ld(6, &fprs[6 * offset]);
	fpu_ld(7, &fprs[7 * offset]);
	fpu_ld(8, &fprs[8 * offset]);
	fpu_ld(9, &fprs[9 * offset]);
	fpu_ld(10, &fprs[10 * offset]);
	fpu_ld(11, &fprs[11 * offset]);
	fpu_ld(12, &fprs[12 * offset]);
	fpu_ld(13, &fprs[13 * offset]);
	fpu_ld(14, &fprs[14 * offset]);
	fpu_ld(15, &fprs[15 * offset]);
	}

	static __always_inline void save_fp_regs(freg_t *fprs)
	{
	__save_fp_regs(fprs, sizeof(freg_t) / sizeof(freg_t));
	}

	static __always_inline void load_fp_regs(freg_t *fprs)
	{
	__load_fp_regs(fprs, sizeof(freg_t) / sizeof(freg_t));
	}

	static __always_inline void save_fp_regs_vx(__vector128 *vxrs)
	{
	freg_t fprs = (freg_t )&vxrs[0].high;

	__save_fp_regs(fprs, sizeof(__vector128) / sizeof(freg_t));
	}

	static __always_inline void load_fp_regs_vx(__vector128 *vxrs)
	{
	freg_t fprs = (freg_t )&vxrs[0].high;

	__load_fp_regs(fprs, sizeof(__vector128) / sizeof(freg_t));
	}

	static inline void load_user_fpu_regs(void)
	{
	struct thread_struct *thread = &current->thread;

	if (!thread->ufpu_flags)
	return;
	load_fpu_state(&thread->ufpu, thread->ufpu_flags);
	thread->ufpu_flags = 0;
	}

	static __always_inline void __save_user_fpu_regs(struct thread_struct *thread, int flags)
	{
	save_fpu_state(&thread->ufpu, flags);
	__atomic_or(flags, &thread->ufpu_flags);
	}

	static inline void save_user_fpu_regs(void)
	{
	struct thread_struct *thread = &current->thread;
	int mask, flags;

	mask = __atomic_or(KERNEL_FPC \| KERNEL_VXR, &thread->kfpu_flags);
	flags = ~READ_ONCE(thread->ufpu_flags) & (KERNEL_FPC \| KERNEL_VXR);
	if (flags)
	__save_user_fpu_regs(thread, flags);
	barrier();
	WRITE_ONCE(thread->kfpu_flags, mask);
	}

	static __always_inline void _kernel_fpu_begin(struct kernel_fpu *state, int flags)
	{
	struct thread_struct *thread = &current->thread;
	int mask, uflags;

	mask = __atomic_or(flags, &thread->kfpu_flags);
	state->hdr.mask = mask;
	uflags = READ_ONCE(thread->ufpu_flags);
	if ((uflags & flags) != flags)
	__save_user_fpu_regs(thread, ~uflags & flags);
	if (mask & flags)
	__kernel_fpu_begin(state, flags);
	}

	static __always_inline void _kernel_fpu_end(struct kernel_fpu *state, int flags)
	{
	int mask = state->hdr.mask;

	if (mask & flags)
	__kernel_fpu_end(state, flags);
	barrier();
	WRITE_ONCE(current->thread.kfpu_flags, mask);
	}

	void __kernel_fpu_invalid_size(void);

	static __always_inline void kernel_fpu_check_size(int flags, unsigned int size)
	{
	unsigned int cnt = 0;

	if (flags & KERNEL_VXR_V0V7)
	cnt += 8;
	if (flags & KERNEL_VXR_V8V15)
	cnt += 8;
	if (flags & KERNEL_VXR_V16V23)
	cnt += 8;
	if (flags & KERNEL_VXR_V24V31)
	cnt += 8;
	if (cnt != size)
	__kernel_fpu_invalid_size();
	}

	#define kernel_fpu_begin(state, flags) \
	{ \
	typeof(state) s = (state); \
	int _flags = (flags); \
	\
	kernel_fpu_check_size(_flags, ARRAY_SIZE(s->vxrs)); \
	_kernel_fpu_begin((struct kernel_fpu *)s, _flags); \
	}

	#define kernel_fpu_end(state, flags) \
	{ \
	typeof(state) s = (state); \
	int _flags = (flags); \
	\
	kernel_fpu_check_size(_flags, ARRAY_SIZE(s->vxrs)); \
	_kernel_fpu_end((struct kernel_fpu *)s, _flags); \
	}

	static inline void save_kernel_fpu_regs(struct thread_struct *thread)
	{
	if (!thread->kfpu_flags)
	return;
	save_fpu_state(&thread->kfpu, thread->kfpu_flags);
	}

	static inline void restore_kernel_fpu_regs(struct thread_struct *thread)
	{
	if (!thread->kfpu_flags)
	return;
	load_fpu_state(&thread->kfpu, thread->kfpu_flags);
	}

	static inline void convert_vx_to_fp(freg_t fprs, __vector128 vxrs)
	{
	int i;

	for (i = 0; i < __NUM_FPRS; i++)
	fprs[i].ui = vxrs[i].high;
	}

	static inline void convert_fp_to_vx(__vector128 vxrs, freg_t fprs)
	{
	int i;

	for (i = 0; i < __NUM_FPRS; i++)
	vxrs[i].high = fprs[i].ui;
	}

	static inline void fpregs_store(_s390_fp_regs fpregs, struct fpu fpu)
	{
	fpregs->pad = 0;
	fpregs->fpc = fpu->fpc;
	convert_vx_to_fp((freg_t *)&fpregs->fprs, fpu->vxrs);
	}

	static inline void fpregs_load(_s390_fp_regs fpregs, struct fpu fpu)
	{
	fpu->fpc = fpregs->fpc;
	convert_fp_to_vx(fpu->vxrs, (freg_t *)&fpregs->fprs);
	}

	#endif /* _ASM_S390_FPU_H */