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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2012 Regents of the University of California
*/
#ifndef _ASM_RISCV_SWITCH_TO_H
#define _ASM_RISCV_SWITCH_TO_H
#include <linux/jump_label.h>
#include <linux/sched/task_stack.h>
#include <linux/mm_types.h>
#include <asm/vector.h>
#include <asm/cpufeature.h>
#include <asm/processor.h>
#include <asm/ptrace.h>
#include <asm/csr.h>
#ifdef CONFIG_FPU
extern void __fstate_save(struct task_struct *save_to);
extern void __fstate_restore(struct task_struct *restore_from);
static inline void __fstate_clean(struct pt_regs *regs)
{
regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN;
}
static inline void fstate_off(struct task_struct *task,
struct pt_regs *regs)
{
regs->status = (regs->status & ~SR_FS) | SR_FS_OFF;
}
static inline void fstate_save(struct task_struct *task,
struct pt_regs *regs)
{
if ((regs->status & SR_FS) == SR_FS_DIRTY) {
__fstate_save(task);
__fstate_clean(regs);
}
}
static inline void fstate_restore(struct task_struct *task,
struct pt_regs *regs)
{
if ((regs->status & SR_FS) != SR_FS_OFF) {
__fstate_restore(task);
__fstate_clean(regs);
}
}
static inline void __switch_to_fpu(struct task_struct *prev,
struct task_struct *next)
{
struct pt_regs *regs;
regs = task_pt_regs(prev);
fstate_save(prev, regs);
fstate_restore(next, task_pt_regs(next));
}
static __always_inline bool has_fpu(void)
{
return riscv_has_extension_likely(RISCV_ISA_EXT_f) ||
riscv_has_extension_likely(RISCV_ISA_EXT_d);
}
#else
static __always_inline bool has_fpu(void) { return false; }
#define fstate_save(task, regs) do { } while (0)
#define fstate_restore(task, regs) do { } while (0)
#define __switch_to_fpu(__prev, __next) do { } while (0)
#endif
extern struct task_struct *__switch_to(struct task_struct *,
struct task_struct *);
static inline bool switch_to_should_flush_icache(struct task_struct *task)
{
#ifdef CONFIG_SMP
bool stale_mm = task->mm && task->mm->context.force_icache_flush;
bool stale_thread = task->thread.force_icache_flush;
bool thread_migrated = smp_processor_id() != task->thread.prev_cpu;
return thread_migrated && (stale_mm || stale_thread);
#else
return false;
#endif
}
#ifdef CONFIG_SMP
#define __set_prev_cpu(thread) ((thread).prev_cpu = smp_processor_id())
#else
#define __set_prev_cpu(thread)
#endif
#define switch_to(prev, next, last) \
do { \
struct task_struct *__prev = (prev); \
struct task_struct *__next = (next); \
__set_prev_cpu(__prev->thread); \
if (has_fpu()) \
__switch_to_fpu(__prev, __next); \
if (has_vector()) \
__switch_to_vector(__prev, __next); \
if (switch_to_should_flush_icache(__next)) \
local_flush_icache_all(); \
((last) = __switch_to(__prev, __next)); \
} while (0)
#endif /* _ASM_RISCV_SWITCH_TO_H */
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