1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */ 2*4882a593Smuzhiyun #ifndef _LINUX_SCHED_TASK_STACK_H 3*4882a593Smuzhiyun #define _LINUX_SCHED_TASK_STACK_H 4*4882a593Smuzhiyun 5*4882a593Smuzhiyun /* 6*4882a593Smuzhiyun * task->stack (kernel stack) handling interfaces: 7*4882a593Smuzhiyun */ 8*4882a593Smuzhiyun 9*4882a593Smuzhiyun #include <linux/sched.h> 10*4882a593Smuzhiyun #include <linux/magic.h> 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun #ifdef CONFIG_THREAD_INFO_IN_TASK 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun /* 15*4882a593Smuzhiyun * When accessing the stack of a non-current task that might exit, use 16*4882a593Smuzhiyun * try_get_task_stack() instead. task_stack_page will return a pointer 17*4882a593Smuzhiyun * that could get freed out from under you. 18*4882a593Smuzhiyun */ task_stack_page(const struct task_struct * task)19*4882a593Smuzhiyunstatic inline void *task_stack_page(const struct task_struct *task) 20*4882a593Smuzhiyun { 21*4882a593Smuzhiyun return task->stack; 22*4882a593Smuzhiyun } 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun #define setup_thread_stack(new,old) do { } while(0) 25*4882a593Smuzhiyun end_of_stack(const struct task_struct * task)26*4882a593Smuzhiyunstatic inline unsigned long *end_of_stack(const struct task_struct *task) 27*4882a593Smuzhiyun { 28*4882a593Smuzhiyun #ifdef CONFIG_STACK_GROWSUP 29*4882a593Smuzhiyun return (unsigned long *)((unsigned long)task->stack + THREAD_SIZE) - 1; 30*4882a593Smuzhiyun #else 31*4882a593Smuzhiyun return task->stack; 32*4882a593Smuzhiyun #endif 33*4882a593Smuzhiyun } 34*4882a593Smuzhiyun 35*4882a593Smuzhiyun #elif !defined(__HAVE_THREAD_FUNCTIONS) 36*4882a593Smuzhiyun 37*4882a593Smuzhiyun #define task_stack_page(task) ((void *)(task)->stack) 38*4882a593Smuzhiyun setup_thread_stack(struct task_struct * p,struct task_struct * org)39*4882a593Smuzhiyunstatic inline void setup_thread_stack(struct task_struct *p, struct task_struct *org) 40*4882a593Smuzhiyun { 41*4882a593Smuzhiyun *task_thread_info(p) = *task_thread_info(org); 42*4882a593Smuzhiyun task_thread_info(p)->task = p; 43*4882a593Smuzhiyun } 44*4882a593Smuzhiyun 45*4882a593Smuzhiyun /* 46*4882a593Smuzhiyun * Return the address of the last usable long on the stack. 47*4882a593Smuzhiyun * 48*4882a593Smuzhiyun * When the stack grows down, this is just above the thread 49*4882a593Smuzhiyun * info struct. Going any lower will corrupt the threadinfo. 50*4882a593Smuzhiyun * 51*4882a593Smuzhiyun * When the stack grows up, this is the highest address. 52*4882a593Smuzhiyun * Beyond that position, we corrupt data on the next page. 53*4882a593Smuzhiyun */ end_of_stack(struct task_struct * p)54*4882a593Smuzhiyunstatic inline unsigned long *end_of_stack(struct task_struct *p) 55*4882a593Smuzhiyun { 56*4882a593Smuzhiyun #ifdef CONFIG_STACK_GROWSUP 57*4882a593Smuzhiyun return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1; 58*4882a593Smuzhiyun #else 59*4882a593Smuzhiyun return (unsigned long *)(task_thread_info(p) + 1); 60*4882a593Smuzhiyun #endif 61*4882a593Smuzhiyun } 62*4882a593Smuzhiyun 63*4882a593Smuzhiyun #endif 64*4882a593Smuzhiyun 65*4882a593Smuzhiyun #ifdef CONFIG_THREAD_INFO_IN_TASK try_get_task_stack(struct task_struct * tsk)66*4882a593Smuzhiyunstatic inline void *try_get_task_stack(struct task_struct *tsk) 67*4882a593Smuzhiyun { 68*4882a593Smuzhiyun return refcount_inc_not_zero(&tsk->stack_refcount) ? 69*4882a593Smuzhiyun task_stack_page(tsk) : NULL; 70*4882a593Smuzhiyun } 71*4882a593Smuzhiyun 72*4882a593Smuzhiyun extern void put_task_stack(struct task_struct *tsk); 73*4882a593Smuzhiyun #else try_get_task_stack(struct task_struct * tsk)74*4882a593Smuzhiyunstatic inline void *try_get_task_stack(struct task_struct *tsk) 75*4882a593Smuzhiyun { 76*4882a593Smuzhiyun return task_stack_page(tsk); 77*4882a593Smuzhiyun } 78*4882a593Smuzhiyun put_task_stack(struct task_struct * tsk)79*4882a593Smuzhiyunstatic inline void put_task_stack(struct task_struct *tsk) {} 80*4882a593Smuzhiyun #endif 81*4882a593Smuzhiyun 82*4882a593Smuzhiyun #define task_stack_end_corrupted(task) \ 83*4882a593Smuzhiyun (*(end_of_stack(task)) != STACK_END_MAGIC) 84*4882a593Smuzhiyun object_is_on_stack(const void * obj)85*4882a593Smuzhiyunstatic inline int object_is_on_stack(const void *obj) 86*4882a593Smuzhiyun { 87*4882a593Smuzhiyun void *stack = task_stack_page(current); 88*4882a593Smuzhiyun 89*4882a593Smuzhiyun return (obj >= stack) && (obj < (stack + THREAD_SIZE)); 90*4882a593Smuzhiyun } 91*4882a593Smuzhiyun 92*4882a593Smuzhiyun extern void thread_stack_cache_init(void); 93*4882a593Smuzhiyun 94*4882a593Smuzhiyun #ifdef CONFIG_DEBUG_STACK_USAGE stack_not_used(struct task_struct * p)95*4882a593Smuzhiyunstatic inline unsigned long stack_not_used(struct task_struct *p) 96*4882a593Smuzhiyun { 97*4882a593Smuzhiyun unsigned long *n = end_of_stack(p); 98*4882a593Smuzhiyun 99*4882a593Smuzhiyun do { /* Skip over canary */ 100*4882a593Smuzhiyun # ifdef CONFIG_STACK_GROWSUP 101*4882a593Smuzhiyun n--; 102*4882a593Smuzhiyun # else 103*4882a593Smuzhiyun n++; 104*4882a593Smuzhiyun # endif 105*4882a593Smuzhiyun } while (!*n); 106*4882a593Smuzhiyun 107*4882a593Smuzhiyun # ifdef CONFIG_STACK_GROWSUP 108*4882a593Smuzhiyun return (unsigned long)end_of_stack(p) - (unsigned long)n; 109*4882a593Smuzhiyun # else 110*4882a593Smuzhiyun return (unsigned long)n - (unsigned long)end_of_stack(p); 111*4882a593Smuzhiyun # endif 112*4882a593Smuzhiyun } 113*4882a593Smuzhiyun #endif 114*4882a593Smuzhiyun extern void set_task_stack_end_magic(struct task_struct *tsk); 115*4882a593Smuzhiyun 116*4882a593Smuzhiyun #ifndef __HAVE_ARCH_KSTACK_END kstack_end(void * addr)117*4882a593Smuzhiyunstatic inline int kstack_end(void *addr) 118*4882a593Smuzhiyun { 119*4882a593Smuzhiyun /* Reliable end of stack detection: 120*4882a593Smuzhiyun * Some APM bios versions misalign the stack 121*4882a593Smuzhiyun */ 122*4882a593Smuzhiyun return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*))); 123*4882a593Smuzhiyun } 124*4882a593Smuzhiyun #endif 125*4882a593Smuzhiyun 126*4882a593Smuzhiyun #endif /* _LINUX_SCHED_TASK_STACK_H */ 127