projects / thirdparty / kernel / stable.git / blame
| Commit | Line | Data |
|---|---|---|
| f05e798a DH |
1 | #ifndef _ASM_X86_SWITCH_TO_H |
| 2 | #define _ASM_X86_SWITCH_TO_H | |
| 3 | ||
| 4 | struct task_struct; /* one of the stranger aspects of C forward declarations */ | |
| 0100301b BG |
5 | |
| 6 | struct task_struct *__switch_to_asm(struct task_struct *prev, | |
| 7 | struct task_struct *next); | |
| 8 | ||
| 35ea7903 | 9 | __visible struct task_struct *__switch_to(struct task_struct *prev, |
| 0100301b | 10 | struct task_struct *next); |
| f05e798a DH |
11 | struct tss_struct; |
| 12 | void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, | |
| 13 | struct tss_struct *tss); | |
| 14 | ||
| e37e43a4 AL |
15 | /* This runs runs on the previous thread's stack. */ |
| 16 | static inline void prepare_switch_to(struct task_struct *prev, | |
| 17 | struct task_struct *next) | |
| 18 | { | |
| 19 | #ifdef CONFIG_VMAP_STACK | |
| 20 | /* | |
| 21 | * If we switch to a stack that has a top-level paging entry | |
| 22 | * that is not present in the current mm, the resulting #PF will | |
| 23 | * will be promoted to a double-fault and we'll panic. Probe | |
| 24 | * the new stack now so that vmalloc_fault can fix up the page | |
| 25 | * tables if needed. This can only happen if we use a stack | |
| 26 | * in vmap space. | |
| 27 | * | |
| 28 | * We assume that the stack is aligned so that it never spans | |
| 29 | * more than one top-level paging entry. | |
| 30 | * | |
| 31 | * To minimize cache pollution, just follow the stack pointer. | |
| 32 | */ | |
| 33 | READ_ONCE(*(unsigned char *)next->thread.sp); | |
| 34 | #endif | |
| 35 | } | |
| 36 | ||
| 616d2483 BG |
37 | asmlinkage void ret_from_fork(void); |
| 38 | ||
| 2c96b2fe JP |
39 | /* |
| 40 | * This is the structure pointed to by thread.sp for an inactive task. The | |
| 41 | * order of the fields must match the code in __switch_to_asm(). | |
| 42 | */ | |
| 7b32aead | 43 | struct inactive_task_frame { |
| 0100301b BG |
44 | #ifdef CONFIG_X86_64 |
| 45 | unsigned long r15; | |
| 46 | unsigned long r14; | |
| 47 | unsigned long r13; | |
| 48 | unsigned long r12; | |
| 49 | #else | |
| 50 | unsigned long si; | |
| 51 | unsigned long di; | |
| 52 | #endif | |
| 53 | unsigned long bx; | |
| 2c96b2fe JP |
54 | |
| 55 | /* | |
| 56 | * These two fields must be together. They form a stack frame header, | |
| 57 | * needed by get_frame_pointer(). | |
| 58 | */ | |
| 7b32aead | 59 | unsigned long bp; |
| 0100301b | 60 | unsigned long ret_addr; |
| 7b32aead BG |
61 | }; |
| 62 | ||
| 0100301b BG |
63 | struct fork_frame { |
| 64 | struct inactive_task_frame frame; | |
| 65 | struct pt_regs regs; | |
| 66 | }; | |
| f05e798a | 67 | |
| f05e798a DH |
68 | #define switch_to(prev, next, last) \ |
| 69 | do { \ | |
| e37e43a4 AL |
70 | prepare_switch_to(prev, next); \ |
| 71 | \ | |
| 0100301b | 72 | ((last) = __switch_to_asm((prev), (next))); \ |
| f05e798a DH |
73 | } while (0) |
| 74 | ||
| bd7dc5a6 AL |
75 | #ifdef CONFIG_X86_32 |
| 76 | static inline void refresh_sysenter_cs(struct thread_struct *thread) | |
| 77 | { | |
| 78 | /* Only happens when SEP is enabled, no need to test "SEP"arately: */ | |
| 79 | if (unlikely(this_cpu_read(cpu_tss.x86_tss.ss1) == thread->sysenter_cs)) | |
| 80 | return; | |
| 81 | ||
| 82 | this_cpu_write(cpu_tss.x86_tss.ss1, thread->sysenter_cs); | |
| 83 | wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0); | |
| 84 | } | |
| 85 | #endif | |
| 86 | ||
| 46f5a10a AL |
87 | /* This is used when switching tasks or entering/exiting vm86 mode. */ |
| 88 | static inline void update_sp0(struct task_struct *task) | |
| 89 | { | |
| 90 | load_sp0(task->thread.sp0); | |
| 91 | } | |
| 92 | ||
| f05e798a | 93 | #endif /* _ASM_X86_SWITCH_TO_H */ |