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