diff options
Diffstat (limited to 'include/linux/scs.h')
| -rw-r--r-- | include/linux/scs.h | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/include/linux/scs.h b/include/linux/scs.h index 6dec390cf154..4ab5bdc898cf 100644 --- a/include/linux/scs.h +++ b/include/linux/scs.h @@ -15,24 +15,18 @@ #ifdef CONFIG_SHADOW_CALL_STACK -/* - * In testing, 1 KiB shadow stack size (i.e. 128 stack frames on a 64-bit - * architecture) provided ~40% safety margin on stack usage while keeping - * memory allocation overhead reasonable. - */ -#define SCS_SIZE SZ_1K +#define SCS_ORDER 0 +#define SCS_SIZE (PAGE_SIZE << SCS_ORDER) #define GFP_SCS (GFP_KERNEL | __GFP_ZERO) /* An illegal pointer value to mark the end of the shadow stack. */ #define SCS_END_MAGIC (0x5f6UL + POISON_POINTER_DELTA) -/* Allocate a static per-CPU shadow stack */ -#define DEFINE_SCS(name) \ - DEFINE_PER_CPU(unsigned long [SCS_SIZE/sizeof(long)], name) \ - #define task_scs(tsk) (task_thread_info(tsk)->scs_base) #define task_scs_sp(tsk) (task_thread_info(tsk)->scs_sp) +void *scs_alloc(int node); +void scs_free(void *s); void scs_init(void); int scs_prepare(struct task_struct *tsk, int node); void scs_release(struct task_struct *tsk); @@ -59,13 +53,33 @@ static inline bool task_scs_end_corrupted(struct task_struct *tsk) return sz >= SCS_SIZE - 1 || READ_ONCE_NOCHECK(*magic) != SCS_END_MAGIC; } +DECLARE_STATIC_KEY_FALSE(dynamic_scs_enabled); + +static inline bool scs_is_dynamic(void) +{ + if (!IS_ENABLED(CONFIG_DYNAMIC_SCS)) + return false; + return static_branch_likely(&dynamic_scs_enabled); +} + +static inline bool scs_is_enabled(void) +{ + if (!IS_ENABLED(CONFIG_DYNAMIC_SCS)) + return true; + return scs_is_dynamic(); +} + #else /* CONFIG_SHADOW_CALL_STACK */ +static inline void *scs_alloc(int node) { return NULL; } +static inline void scs_free(void *s) {} static inline void scs_init(void) {} static inline void scs_task_reset(struct task_struct *tsk) {} static inline int scs_prepare(struct task_struct *tsk, int node) { return 0; } static inline void scs_release(struct task_struct *tsk) {} static inline bool task_scs_end_corrupted(struct task_struct *tsk) { return false; } +static inline bool scs_is_enabled(void) { return false; } +static inline bool scs_is_dynamic(void) { return false; } #endif /* CONFIG_SHADOW_CALL_STACK */ |