cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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switch_to.h (2107B)

      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/processor.h>
     12#include <asm/ptrace.h>
     13#include <asm/csr.h>
     14
     15#ifdef CONFIG_FPU
     16extern void __fstate_save(struct task_struct *save_to);
     17extern void __fstate_restore(struct task_struct *restore_from);
     18
     19static inline void __fstate_clean(struct pt_regs *regs)
     20{
     21	regs->status = (regs->status & ~SR_FS) | SR_FS_CLEAN;
     22}
     23
     24static inline void fstate_off(struct task_struct *task,
     25			      struct pt_regs *regs)
     26{
     27	regs->status = (regs->status & ~SR_FS) | SR_FS_OFF;
     28}
     29
     30static inline void fstate_save(struct task_struct *task,
     31			       struct pt_regs *regs)
     32{
     33	if ((regs->status & SR_FS) == SR_FS_DIRTY) {
     34		__fstate_save(task);
     35		__fstate_clean(regs);
     36	}
     37}
     38
     39static inline void fstate_restore(struct task_struct *task,
     40				  struct pt_regs *regs)
     41{
     42	if ((regs->status & SR_FS) != SR_FS_OFF) {
     43		__fstate_restore(task);
     44		__fstate_clean(regs);
     45	}
     46}
     47
     48static inline void __switch_to_aux(struct task_struct *prev,
     49				   struct task_struct *next)
     50{
     51	struct pt_regs *regs;
     52
     53	regs = task_pt_regs(prev);
     54	if (unlikely(regs->status & SR_SD))
     55		fstate_save(prev, regs);
     56	fstate_restore(next, task_pt_regs(next));
     57}
     58
     59extern struct static_key_false cpu_hwcap_fpu;
     60static __always_inline bool has_fpu(void)
     61{
     62	return static_branch_likely(&cpu_hwcap_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 */