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