diff options
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/compiler-clang.h | 9 | ||||
-rw-r--r-- | include/linux/compiler-gcc.h | 7 | ||||
-rw-r--r-- | include/linux/compiler.h | 37 | ||||
-rw-r--r-- | include/linux/kcsan-checks.h | 97 | ||||
-rw-r--r-- | include/linux/kcsan.h | 115 | ||||
-rw-r--r-- | include/linux/sched.h | 4 |
6 files changed, 261 insertions, 8 deletions
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 333a6695a918..a213eb55e725 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -24,6 +24,15 @@ #define __no_sanitize_address #endif +#if __has_feature(thread_sanitizer) +/* emulate gcc's __SANITIZE_THREAD__ flag */ +#define __SANITIZE_THREAD__ +#define __no_sanitize_thread \ + __attribute__((no_sanitize("thread"))) +#else +#define __no_sanitize_thread +#endif + /* * Not all versions of clang implement the the type-generic versions * of the builtin overflow checkers. Fortunately, clang implements diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index d7ee4c6bad48..0eb2a1cc411d 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -145,6 +145,13 @@ #define __no_sanitize_address #endif +#if defined(__SANITIZE_THREAD__) && __has_attribute(__no_sanitize_thread__) +#define __no_sanitize_thread \ + __attribute__((__noinline__)) __attribute__((no_sanitize_thread)) +#else +#define __no_sanitize_thread +#endif + #if GCC_VERSION >= 50100 #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 #endif diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 5e88e7e33abe..c42fa83f23fb 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -178,6 +178,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, #endif #include <uapi/linux/types.h> +#include <linux/kcsan-checks.h> #define __READ_ONCE_SIZE \ ({ \ @@ -193,12 +194,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, } \ }) -static __always_inline -void __read_once_size(const volatile void *p, void *res, int size) -{ - __READ_ONCE_SIZE; -} - #ifdef CONFIG_KASAN /* * We can't declare function 'inline' because __no_sanitize_address confilcts @@ -207,18 +202,44 @@ void __read_once_size(const volatile void *p, void *res, int size) * '__maybe_unused' allows us to avoid defined-but-not-used warnings. */ # define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused +# define __no_sanitize_or_inline __no_kasan_or_inline #else # define __no_kasan_or_inline __always_inline #endif -static __no_kasan_or_inline +#ifdef __SANITIZE_THREAD__ +/* + * Rely on __SANITIZE_THREAD__ instead of CONFIG_KCSAN, to avoid not inlining in + * compilation units where instrumentation is disabled. + */ +# define __no_kcsan_or_inline __no_sanitize_thread notrace __maybe_unused +# define __no_sanitize_or_inline __no_kcsan_or_inline +#else +# define __no_kcsan_or_inline __always_inline +#endif + +#ifndef __no_sanitize_or_inline +#define __no_sanitize_or_inline __always_inline +#endif + +static __no_kcsan_or_inline +void __read_once_size(const volatile void *p, void *res, int size) +{ + kcsan_check_atomic_read(p, size); + __READ_ONCE_SIZE; +} + +static __no_sanitize_or_inline void __read_once_size_nocheck(const volatile void *p, void *res, int size) { __READ_ONCE_SIZE; } -static __always_inline void __write_once_size(volatile void *p, void *res, int size) +static __no_kcsan_or_inline +void __write_once_size(volatile void *p, void *res, int size) { + kcsan_check_atomic_write(p, size); + switch (size) { case 1: *(volatile __u8 *)p = *(__u8 *)res; break; case 2: *(volatile __u16 *)p = *(__u16 *)res; break; diff --git a/include/linux/kcsan-checks.h b/include/linux/kcsan-checks.h new file mode 100644 index 000000000000..e78220661086 --- /dev/null +++ b/include/linux/kcsan-checks.h @@ -0,0 +1,97 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_KCSAN_CHECKS_H +#define _LINUX_KCSAN_CHECKS_H + +#include <linux/types.h> + +/* + * Access type modifiers. + */ +#define KCSAN_ACCESS_WRITE 0x1 +#define KCSAN_ACCESS_ATOMIC 0x2 + +/* + * __kcsan_*: Always calls into runtime when KCSAN is enabled. This may be used + * even in compilation units that selectively disable KCSAN, but must use KCSAN + * to validate access to an address. Never use these in header files! + */ +#ifdef CONFIG_KCSAN +/** + * __kcsan_check_access - check generic access for data race + * + * @ptr address of access + * @size size of access + * @type access type modifier + */ +void __kcsan_check_access(const volatile void *ptr, size_t size, int type); + +#else +static inline void __kcsan_check_access(const volatile void *ptr, size_t size, + int type) { } +#endif + +/* + * kcsan_*: Only calls into runtime when the particular compilation unit has + * KCSAN instrumentation enabled. May be used in header files. + */ +#ifdef __SANITIZE_THREAD__ +#define kcsan_check_access __kcsan_check_access +#else +static inline void kcsan_check_access(const volatile void *ptr, size_t size, + int type) { } +#endif + +/** + * __kcsan_check_read - check regular read access for data races + * + * @ptr address of access + * @size size of access + */ +#define __kcsan_check_read(ptr, size) __kcsan_check_access(ptr, size, 0) + +/** + * __kcsan_check_write - check regular write access for data races + * + * @ptr address of access + * @size size of access + */ +#define __kcsan_check_write(ptr, size) \ + __kcsan_check_access(ptr, size, KCSAN_ACCESS_WRITE) + +/** + * kcsan_check_read - check regular read access for data races + * + * @ptr address of access + * @size size of access + */ +#define kcsan_check_read(ptr, size) kcsan_check_access(ptr, size, 0) + +/** + * kcsan_check_write - check regular write access for data races + * + * @ptr address of access + * @size size of access + */ +#define kcsan_check_write(ptr, size) \ + kcsan_check_access(ptr, size, KCSAN_ACCESS_WRITE) + +/* + * Check for atomic accesses: if atomic access are not ignored, this simply + * aliases to kcsan_check_access, otherwise becomes a no-op. + */ +#ifdef CONFIG_KCSAN_IGNORE_ATOMICS +#define kcsan_check_atomic_read(...) \ + do { \ + } while (0) +#define kcsan_check_atomic_write(...) \ + do { \ + } while (0) +#else +#define kcsan_check_atomic_read(ptr, size) \ + kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC) +#define kcsan_check_atomic_write(ptr, size) \ + kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC | KCSAN_ACCESS_WRITE) +#endif + +#endif /* _LINUX_KCSAN_CHECKS_H */ diff --git a/include/linux/kcsan.h b/include/linux/kcsan.h new file mode 100644 index 000000000000..9047048fee84 --- /dev/null +++ b/include/linux/kcsan.h @@ -0,0 +1,115 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_KCSAN_H +#define _LINUX_KCSAN_H + +#include <linux/kcsan-checks.h> +#include <linux/types.h> + +#ifdef CONFIG_KCSAN + +/* + * Context for each thread of execution: for tasks, this is stored in + * task_struct, and interrupts access internal per-CPU storage. + */ +struct kcsan_ctx { + int disable_count; /* disable counter */ + int atomic_next; /* number of following atomic ops */ + + /* + * We distinguish between: (a) nestable atomic regions that may contain + * other nestable regions; and (b) flat atomic regions that do not keep + * track of nesting. Both (a) and (b) are entirely independent of each + * other, and a flat region may be started in a nestable region or + * vice-versa. + * + * This is required because, for example, in the annotations for + * seqlocks, we declare seqlock writer critical sections as (a) nestable + * atomic regions, but reader critical sections as (b) flat atomic + * regions, but have encountered cases where seqlock reader critical + * sections are contained within writer critical sections (the opposite + * may be possible, too). + * + * To support these cases, we independently track the depth of nesting + * for (a), and whether the leaf level is flat for (b). + */ + int atomic_nest_count; + bool in_flat_atomic; +}; + +/** + * kcsan_init - initialize KCSAN runtime + */ +void kcsan_init(void); + +/** + * kcsan_disable_current - disable KCSAN for the current context + * + * Supports nesting. + */ +void kcsan_disable_current(void); + +/** + * kcsan_enable_current - re-enable KCSAN for the current context + * + * Supports nesting. + */ +void kcsan_enable_current(void); + +/** + * kcsan_nestable_atomic_begin - begin nestable atomic region + * + * Accesses within the atomic region may appear to race with other accesses but + * should be considered atomic. + */ +void kcsan_nestable_atomic_begin(void); + +/** + * kcsan_nestable_atomic_end - end nestable atomic region + */ +void kcsan_nestable_atomic_end(void); + +/** + * kcsan_flat_atomic_begin - begin flat atomic region + * + * Accesses within the atomic region may appear to race with other accesses but + * should be considered atomic. + */ +void kcsan_flat_atomic_begin(void); + +/** + * kcsan_flat_atomic_end - end flat atomic region + */ +void kcsan_flat_atomic_end(void); + +/** + * kcsan_atomic_next - consider following accesses as atomic + * + * Force treating the next n memory accesses for the current context as atomic + * operations. + * + * @n number of following memory accesses to treat as atomic. + */ +void kcsan_atomic_next(int n); + +#else /* CONFIG_KCSAN */ + +static inline void kcsan_init(void) { } + +static inline void kcsan_disable_current(void) { } + +static inline void kcsan_enable_current(void) { } + +static inline void kcsan_nestable_atomic_begin(void) { } + +static inline void kcsan_nestable_atomic_end(void) { } + +static inline void kcsan_flat_atomic_begin(void) { } + +static inline void kcsan_flat_atomic_end(void) { } + +static inline void kcsan_atomic_next(int n) { } + +#endif /* CONFIG_KCSAN */ + +#endif /* _LINUX_KCSAN_H */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 67a1d86981a9..ae4f341c1db4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -31,6 +31,7 @@ #include <linux/task_io_accounting.h> #include <linux/posix-timers.h> #include <linux/rseq.h> +#include <linux/kcsan.h> /* task_struct member predeclarations (sorted alphabetically): */ struct audit_context; @@ -1172,6 +1173,9 @@ struct task_struct { #ifdef CONFIG_KASAN unsigned int kasan_depth; #endif +#ifdef CONFIG_KCSAN + struct kcsan_ctx kcsan_ctx; +#endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* Index of current stored address in ret_stack: */ |