123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_TASK_STACK_H
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#define _LINUX_SCHED_TASK_STACK_H
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/*
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* task->stack (kernel stack) handling interfaces:
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*/
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#include <linux/sched.h>
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#include <linux/magic.h>
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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/*
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* When accessing the stack of a non-current task that might exit, use
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* try_get_task_stack() instead. task_stack_page will return a pointer
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* that could get freed out from under you.
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*/
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static inline void *task_stack_page(const struct task_struct *task)
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{
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return task->stack;
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}
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#define setup_thread_stack(new,old) do { } while(0)
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static inline unsigned long *end_of_stack(const struct task_struct *task)
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{
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return task->stack;
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}
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#elif !defined(__HAVE_THREAD_FUNCTIONS)
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#define task_stack_page(task) ((void *)(task)->stack)
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static inline void setup_thread_stack(struct task_struct *p, struct task_struct *org)
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{
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*task_thread_info(p) = *task_thread_info(org);
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task_thread_info(p)->task = p;
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}
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/*
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* Return the address of the last usable long on the stack.
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*
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* When the stack grows down, this is just above the thread
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* info struct. Going any lower will corrupt the threadinfo.
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*
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* When the stack grows up, this is the highest address.
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* Beyond that position, we corrupt data on the next page.
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*/
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static inline unsigned long *end_of_stack(struct task_struct *p)
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{
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#ifdef CONFIG_STACK_GROWSUP
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return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1;
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#else
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return (unsigned long *)(task_thread_info(p) + 1);
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#endif
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}
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#endif
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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static inline void *try_get_task_stack(struct task_struct *tsk)
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{
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return atomic_inc_not_zero(&tsk->stack_refcount) ?
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task_stack_page(tsk) : NULL;
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}
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extern void put_task_stack(struct task_struct *tsk);
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#else
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static inline void *try_get_task_stack(struct task_struct *tsk)
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{
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return task_stack_page(tsk);
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}
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static inline void put_task_stack(struct task_struct *tsk) {}
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#endif
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#define task_stack_end_corrupted(task) \
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(*(end_of_stack(task)) != STACK_END_MAGIC)
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static inline int object_is_on_stack(const void *obj)
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{
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void *stack = task_stack_page(current);
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return (obj >= stack) && (obj < (stack + THREAD_SIZE));
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}
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extern void thread_stack_cache_init(void);
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#ifdef CONFIG_DEBUG_STACK_USAGE
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static inline unsigned long stack_not_used(struct task_struct *p)
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{
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unsigned long *n = end_of_stack(p);
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do { /* Skip over canary */
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# ifdef CONFIG_STACK_GROWSUP
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n--;
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# else
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n++;
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# endif
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} while (!*n);
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# ifdef CONFIG_STACK_GROWSUP
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return (unsigned long)end_of_stack(p) - (unsigned long)n;
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# else
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return (unsigned long)n - (unsigned long)end_of_stack(p);
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# endif
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}
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#endif
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extern void set_task_stack_end_magic(struct task_struct *tsk);
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#ifndef __HAVE_ARCH_KSTACK_END
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static inline int kstack_end(void *addr)
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{
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/* Reliable end of stack detection:
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* Some APM bios versions misalign the stack
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*/
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return !(((unsigned long)addr+sizeof(void*)-1) & (THREAD_SIZE-sizeof(void*)));
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}
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#endif
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#endif /* _LINUX_SCHED_TASK_STACK_H */
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