mirror of https://gitee.com/openkylin/linux.git
76 lines
2.0 KiB
C
76 lines
2.0 KiB
C
#ifndef _ASM_X86_SWITCH_TO_H
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#define _ASM_X86_SWITCH_TO_H
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struct task_struct; /* one of the stranger aspects of C forward declarations */
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struct task_struct *__switch_to_asm(struct task_struct *prev,
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struct task_struct *next);
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__visible struct task_struct *__switch_to(struct task_struct *prev,
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struct task_struct *next);
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struct tss_struct;
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void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
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struct tss_struct *tss);
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/* This runs runs on the previous thread's stack. */
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static inline void prepare_switch_to(struct task_struct *prev,
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struct task_struct *next)
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{
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#ifdef CONFIG_VMAP_STACK
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/*
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* If we switch to a stack that has a top-level paging entry
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* that is not present in the current mm, the resulting #PF will
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* will be promoted to a double-fault and we'll panic. Probe
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* the new stack now so that vmalloc_fault can fix up the page
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* tables if needed. This can only happen if we use a stack
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* in vmap space.
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*
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* We assume that the stack is aligned so that it never spans
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* more than one top-level paging entry.
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*
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* To minimize cache pollution, just follow the stack pointer.
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*/
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READ_ONCE(*(unsigned char *)next->thread.sp);
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#endif
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}
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asmlinkage void ret_from_fork(void);
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/*
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* This is the structure pointed to by thread.sp for an inactive task. The
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* order of the fields must match the code in __switch_to_asm().
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*/
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struct inactive_task_frame {
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#ifdef CONFIG_X86_64
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unsigned long r15;
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unsigned long r14;
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unsigned long r13;
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unsigned long r12;
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#else
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unsigned long si;
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unsigned long di;
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#endif
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unsigned long bx;
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/*
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* These two fields must be together. They form a stack frame header,
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* needed by get_frame_pointer().
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*/
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unsigned long bp;
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unsigned long ret_addr;
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};
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struct fork_frame {
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struct inactive_task_frame frame;
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struct pt_regs regs;
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};
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#define switch_to(prev, next, last) \
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do { \
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prepare_switch_to(prev, next); \
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\
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((last) = __switch_to_asm((prev), (next))); \
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} while (0)
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#endif /* _ASM_X86_SWITCH_TO_H */
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