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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/jump_label.h>
10#include <linux/sched/task_stack.h>
11#include <asm/vector.h>
12#include <asm/cpufeature.h>
13#include <asm/processor.h>
14#include <asm/ptrace.h>
15#include <asm/csr.h>
16
17#ifdef CONFIG_FPU
18extern void __fstate_save(struct task_struct *save_to);
19extern void __fstate_restore(struct task_struct *restore_from);
20
21static inline void __fstate_clean(struct pt_regs *regs)
22{
23 regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN;
24}
25
26static inline void fstate_off(struct task_struct *task,
27 struct pt_regs *regs)
28{
29 regs->status = (regs->status & ~SR_FS) | SR_FS_OFF;
30}
31
32static inline void fstate_save(struct task_struct *task,
33 struct pt_regs *regs)
34{
35 if ((regs->status & SR_FS) == SR_FS_DIRTY) {
36 __fstate_save(task);
37 __fstate_clean(regs);
38 }
39}
40
41static inline void fstate_restore(struct task_struct *task,
42 struct pt_regs *regs)
43{
44 if ((regs->status & SR_FS) != SR_FS_OFF) {
45 __fstate_restore(task);
46 __fstate_clean(regs);
47 }
48}
49
50static inline void __switch_to_fpu(struct task_struct *prev,
51 struct task_struct *next)
52{
53 struct pt_regs *regs;
54
55 regs = task_pt_regs(prev);
56 if (unlikely(regs->status & SR_SD))
57 fstate_save(prev, regs);
58 fstate_restore(next, task_pt_regs(next));
59}
60
61static __always_inline bool has_fpu(void)
62{
63 return riscv_has_extension_likely(RISCV_ISA_EXT_f) ||
64 riscv_has_extension_likely(RISCV_ISA_EXT_d);
65}
66#else
67static __always_inline bool has_fpu(void) { return false; }
68#define fstate_save(task, regs) do { } while (0)
69#define fstate_restore(task, regs) do { } while (0)
70#define __switch_to_fpu(__prev, __next) do { } while (0)
71#endif
72
73extern struct task_struct *__switch_to(struct task_struct *,
74 struct task_struct *);
75
76#define switch_to(prev, next, last) \
77do { \
78 struct task_struct *__prev = (prev); \
79 struct task_struct *__next = (next); \
80 if (has_fpu()) \
81 __switch_to_fpu(__prev, __next); \
82 if (has_vector()) \
83 __switch_to_vector(__prev, __next); \
84 ((last) = __switch_to(__prev, __next)); \
85} while (0)
86
87#endif /* _ASM_RISCV_SWITCH_TO_H */