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/* SPDX-License-Identifier: GPL-2.0 */
/*
* The Kernel Concurrency Sanitizer (KCSAN) infrastructure. For more info please
* see Documentation/dev-tools/kcsan.rst.
*
* Copyright (C) 2019, Google LLC.
*/
#ifndef _KERNEL_KCSAN_KCSAN_H
#define _KERNEL_KCSAN_KCSAN_H
#include <linux/atomic.h>
#include <linux/kcsan.h>
#include <linux/sched.h>
/* The number of adjacent watchpoints to check. */
#define KCSAN_CHECK_ADJACENT 1
#define NUM_SLOTS (1 + 2*KCSAN_CHECK_ADJACENT)
extern unsigned int kcsan_udelay_task;
extern unsigned int kcsan_udelay_interrupt;
/*
* Globally enable and disable KCSAN.
*/
extern bool kcsan_enabled;
/*
* Save/restore IRQ flags state trace dirtied by KCSAN.
*/
void kcsan_save_irqtrace(struct task_struct *task);
void kcsan_restore_irqtrace(struct task_struct *task);
/*
* Statistics counters displayed via debugfs; should only be modified in
* slow-paths.
*/
enum kcsan_counter_id {
/*
* Number of watchpoints currently in use.
*/
KCSAN_COUNTER_USED_WATCHPOINTS,
/*
* Total number of watchpoints set up.
*/
KCSAN_COUNTER_SETUP_WATCHPOINTS,
/*
* Total number of data races.
*/
KCSAN_COUNTER_DATA_RACES,
/*
* Total number of ASSERT failures due to races. If the observed race is
* due to two conflicting ASSERT type accesses, then both will be
* counted.
*/
KCSAN_COUNTER_ASSERT_FAILURES,
/*
* Number of times no watchpoints were available.
*/
KCSAN_COUNTER_NO_CAPACITY,
/*
* A thread checking a watchpoint raced with another checking thread;
* only one will be reported.
*/
KCSAN_COUNTER_REPORT_RACES,
/*
* Observed data value change, but writer thread unknown.
*/
KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN,
/*
* The access cannot be encoded to a valid watchpoint.
*/
KCSAN_COUNTER_UNENCODABLE_ACCESSES,
/*
* Watchpoint encoding caused a watchpoint to fire on mismatching
* accesses.
*/
KCSAN_COUNTER_ENCODING_FALSE_POSITIVES,
KCSAN_COUNTER_COUNT, /* number of counters */
};
extern atomic_long_t kcsan_counters[KCSAN_COUNTER_COUNT];
/*
* Returns true if data races in the function symbol that maps to func_addr
* (offsets are ignored) should *not* be reported.
*/
extern bool kcsan_skip_report_debugfs(unsigned long func_addr);
/*
* Value-change states.
*/
enum kcsan_value_change {
/*
* Did not observe a value-change, however, it is valid to report the
* race, depending on preferences.
*/
KCSAN_VALUE_CHANGE_MAYBE,
/*
* Did not observe a value-change, and it is invalid to report the race.
*/
KCSAN_VALUE_CHANGE_FALSE,
/*
* The value was observed to change, and the race should be reported.
*/
KCSAN_VALUE_CHANGE_TRUE,
};
/*
* The calling thread hit and consumed a watchpoint: set the access information
* to be consumed by the reporting thread. No report is printed yet.
*/
void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type,
int watchpoint_idx);
/*
* The calling thread observed that the watchpoint it set up was hit and
* consumed: print the full report based on information set by the racing
* thread.
*/
void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type,
enum kcsan_value_change value_change, int watchpoint_idx);
/*
* No other thread was observed to race with the access, but the data value
* before and after the stall differs. Reports a race of "unknown origin".
*/
void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type);
#endif /* _KERNEL_KCSAN_KCSAN_H */
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