cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

preempt.h (2779B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef __ASM_PREEMPT_H
      3#define __ASM_PREEMPT_H
      4
      5#include <linux/jump_label.h>
      6#include <linux/thread_info.h>
      7
      8#define PREEMPT_NEED_RESCHED	BIT(32)
      9#define PREEMPT_ENABLED	(PREEMPT_NEED_RESCHED)
     10
     11static inline int preempt_count(void)
     12{
     13	return READ_ONCE(current_thread_info()->preempt.count);
     14}
     15
     16static inline void preempt_count_set(u64 pc)
     17{
     18	/* Preserve existing value of PREEMPT_NEED_RESCHED */
     19	WRITE_ONCE(current_thread_info()->preempt.count, pc);
     20}
     21
     22#define init_task_preempt_count(p) do { \
     23	task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
     24} while (0)
     25
     26#define init_idle_preempt_count(p, cpu) do { \
     27	task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
     28} while (0)
     29
     30static inline void set_preempt_need_resched(void)
     31{
     32	current_thread_info()->preempt.need_resched = 0;
     33}
     34
     35static inline void clear_preempt_need_resched(void)
     36{
     37	current_thread_info()->preempt.need_resched = 1;
     38}
     39
     40static inline bool test_preempt_need_resched(void)
     41{
     42	return !current_thread_info()->preempt.need_resched;
     43}
     44
     45static inline void __preempt_count_add(int val)
     46{
     47	u32 pc = READ_ONCE(current_thread_info()->preempt.count);
     48	pc += val;
     49	WRITE_ONCE(current_thread_info()->preempt.count, pc);
     50}
     51
     52static inline void __preempt_count_sub(int val)
     53{
     54	u32 pc = READ_ONCE(current_thread_info()->preempt.count);
     55	pc -= val;
     56	WRITE_ONCE(current_thread_info()->preempt.count, pc);
     57}
     58
     59static inline bool __preempt_count_dec_and_test(void)
     60{
     61	struct thread_info *ti = current_thread_info();
     62	u64 pc = READ_ONCE(ti->preempt_count);
     63
     64	/* Update only the count field, leaving need_resched unchanged */
     65	WRITE_ONCE(ti->preempt.count, --pc);
     66
     67	/*
     68	 * If we wrote back all zeroes, then we're preemptible and in
     69	 * need of a reschedule. Otherwise, we need to reload the
     70	 * preempt_count in case the need_resched flag was cleared by an
     71	 * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE
     72	 * pair.
     73	 */
     74	return !pc || !READ_ONCE(ti->preempt_count);
     75}
     76
     77static inline bool should_resched(int preempt_offset)
     78{
     79	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
     80	return pc == preempt_offset;
     81}
     82
     83#ifdef CONFIG_PREEMPTION
     84
     85void preempt_schedule(void);
     86void preempt_schedule_notrace(void);
     87
     88#ifdef CONFIG_PREEMPT_DYNAMIC
     89
     90DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
     91void dynamic_preempt_schedule(void);
     92#define __preempt_schedule()		dynamic_preempt_schedule()
     93void dynamic_preempt_schedule_notrace(void);
     94#define __preempt_schedule_notrace()	dynamic_preempt_schedule_notrace()
     95
     96#else /* CONFIG_PREEMPT_DYNAMIC */
     97
     98#define __preempt_schedule()		preempt_schedule()
     99#define __preempt_schedule_notrace()	preempt_schedule_notrace()
    100
    101#endif /* CONFIG_PREEMPT_DYNAMIC */
    102#endif /* CONFIG_PREEMPTION */
    103
    104#endif /* __ASM_PREEMPT_H */