1afaef01cSAlexander Popov /* SPDX-License-Identifier: GPL-2.0 */ 2afaef01cSAlexander Popov #ifndef _LINUX_STACKLEAK_H 3afaef01cSAlexander Popov #define _LINUX_STACKLEAK_H 4afaef01cSAlexander Popov 5afaef01cSAlexander Popov #include <linux/sched.h> 6afaef01cSAlexander Popov #include <linux/sched/task_stack.h> 7afaef01cSAlexander Popov 8afaef01cSAlexander Popov /* 9afaef01cSAlexander Popov * Check that the poison value points to the unused hole in the 10afaef01cSAlexander Popov * virtual memory map for your platform. 11afaef01cSAlexander Popov */ 12afaef01cSAlexander Popov #define STACKLEAK_POISON -0xBEEF 13afaef01cSAlexander Popov #define STACKLEAK_SEARCH_DEPTH 128 14afaef01cSAlexander Popov 15afaef01cSAlexander Popov #ifdef CONFIG_GCC_PLUGIN_STACKLEAK 16afaef01cSAlexander Popov #include <asm/stacktrace.h> 17afaef01cSAlexander Popov 18*9ec79840SMark Rutland /* 19*9ec79840SMark Rutland * The lowest address on tsk's stack which we can plausibly erase. 20*9ec79840SMark Rutland */ 21*9ec79840SMark Rutland static __always_inline unsigned long 22*9ec79840SMark Rutland stackleak_task_low_bound(const struct task_struct *tsk) 23*9ec79840SMark Rutland { 24*9ec79840SMark Rutland /* 25*9ec79840SMark Rutland * The lowest unsigned long on the task stack contains STACK_END_MAGIC, 26*9ec79840SMark Rutland * which we must not corrupt. 27*9ec79840SMark Rutland */ 28*9ec79840SMark Rutland return (unsigned long)end_of_stack(tsk) + sizeof(unsigned long); 29*9ec79840SMark Rutland } 30*9ec79840SMark Rutland 31afaef01cSAlexander Popov static inline void stackleak_task_init(struct task_struct *t) 32afaef01cSAlexander Popov { 33*9ec79840SMark Rutland t->lowest_stack = stackleak_task_low_bound(t); 34c8d12627SAlexander Popov # ifdef CONFIG_STACKLEAK_METRICS 35c8d12627SAlexander Popov t->prev_lowest_stack = t->lowest_stack; 36c8d12627SAlexander Popov # endif 37afaef01cSAlexander Popov } 38964c9dffSAlexander Popov 39afaef01cSAlexander Popov #else /* !CONFIG_GCC_PLUGIN_STACKLEAK */ 40afaef01cSAlexander Popov static inline void stackleak_task_init(struct task_struct *t) { } 41afaef01cSAlexander Popov #endif 42afaef01cSAlexander Popov 43afaef01cSAlexander Popov #endif 44