1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 Regents of the University of California
4 */
5
6#ifndef _ASM_RISCV_SWITCH_TO_H
7#define _ASM_RISCV_SWITCH_TO_H
8
9#include <linux/sched/task_stack.h>
10#include <asm/processor.h>
11#include <asm/ptrace.h>
12#include <asm/csr.h>
13
14#ifdef CONFIG_FPU
15extern void __fstate_save(struct task_struct *save_to);
16extern void __fstate_restore(struct task_struct *restore_from);
17
18static inline void __fstate_clean(struct pt_regs *regs)
19{
20	regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN;
21}
22
23static inline void fstate_off(struct task_struct *task,
24			      struct pt_regs *regs)
25{
26	regs->status = (regs->status & ~SR_FS) | SR_FS_OFF;
27}
28
29static inline void fstate_save(struct task_struct *task,
30			       struct pt_regs *regs)
31{
32	if ((regs->status & SR_FS) == SR_FS_DIRTY) {
33		__fstate_save(task);
34		__fstate_clean(regs);
35	}
36}
37
38static inline void fstate_restore(struct task_struct *task,
39				  struct pt_regs *regs)
40{
41	if ((regs->status & SR_FS) != SR_FS_OFF) {
42		__fstate_restore(task);
43		__fstate_clean(regs);
44	}
45}
46
47static inline void __switch_to_aux(struct task_struct *prev,
48				   struct task_struct *next)
49{
50	struct pt_regs *regs;
51
52	regs = task_pt_regs(prev);
53	if (unlikely(regs->status & SR_SD))
54		fstate_save(prev, regs);
55	fstate_restore(next, task_pt_regs(next));
56}
57
58extern bool has_fpu;
59#else
60#define has_fpu false
61#define fstate_save(task, regs) do { } while (0)
62#define fstate_restore(task, regs) do { } while (0)
63#define __switch_to_aux(__prev, __next) do { } while (0)
64#endif
65
66extern struct task_struct *__switch_to(struct task_struct *,
67				       struct task_struct *);
68
69#define switch_to(prev, next, last)			\
70do {							\
71	struct task_struct *__prev = (prev);		\
72	struct task_struct *__next = (next);		\
73	if (has_fpu)					\
74		__switch_to_aux(__prev, __next);	\
75	((last) = __switch_to(__prev, __next));		\
76} while (0)
77
78#endif /* _ASM_RISCV_SWITCH_TO_H */
79