1/* thread_info.h: i386 low-level thread information 2 * 3 * Copyright (C) 2002 David Howells (dhowells@redhat.com) 4 * - Incorporating suggestions made by Linus Torvalds and Dave Miller 5 */ 6 7#ifndef _ASM_THREAD_INFO_H 8#define _ASM_THREAD_INFO_H 9 10#ifdef __KERNEL__ 11 12#include <linux/compiler.h> 13#include <asm/page.h> 14 15#ifndef __ASSEMBLY__ 16#include <asm/processor.h> 17#endif 18 19/* 20 * low level task data that entry.S needs immediate access to 21 * - this struct should fit entirely inside of one cache line 22 * - this struct shares the supervisor stack pages 23 * - if the contents of this structure are changed, the assembly constants must also be changed 24 */ 25#ifndef __ASSEMBLY__ 26 27struct thread_info { 28 struct task_struct *task; /* main task structure */ 29 struct exec_domain *exec_domain; /* execution domain */ 30 unsigned long flags; /* low level flags */ 31 unsigned long status; /* thread-synchronous flags */ 32 __u32 cpu; /* current CPU */ 33 int preempt_count; /* 0 => preemptable, <0 => BUG */ 34 35 36 mm_segment_t addr_limit; /* thread address space: 37 0-0xBFFFFFFF for user-thead 38 0-0xFFFFFFFF for kernel-thread 39 */ 40 void *sysenter_return; 41 struct restart_block restart_block; 42 43 unsigned long previous_esp; /* ESP of the previous stack in case 44 of nested (IRQ) stacks 45 */ 46 __u8 supervisor_stack[0]; 47}; 48 49#else /* !__ASSEMBLY__ */ 50 51#include <asm/asm-offsets.h> 52 53#endif 54 55#define PREEMPT_ACTIVE 0x10000000 56#ifdef CONFIG_4KSTACKS 57#define THREAD_SIZE (4096) 58#else 59#define THREAD_SIZE (8192) 60#endif 61 62#define STACK_WARN (THREAD_SIZE/8) 63/* 64 * macros/functions for gaining access to the thread information structure 65 * 66 * preempt_count needs to be 1 initially, until the scheduler is functional. 67 */ 68#ifndef __ASSEMBLY__ 69 70#define INIT_THREAD_INFO(tsk) \ 71{ \ 72 .task = &tsk, \ 73 .exec_domain = &default_exec_domain, \ 74 .flags = 0, \ 75 .cpu = 0, \ 76 .preempt_count = 1, \ 77 .addr_limit = KERNEL_DS, \ 78 .restart_block = { \ 79 .fn = do_no_restart_syscall, \ 80 }, \ 81} 82 83#define init_thread_info (init_thread_union.thread_info) 84#define init_stack (init_thread_union.stack) 85 86 87/* how to get the current stack pointer from C */ 88register unsigned long current_stack_pointer asm("esp") __attribute_used__; 89 90/* how to get the thread information struct from C */ 91static inline struct thread_info *current_thread_info(void) 92{ 93 return (struct thread_info *)(current_stack_pointer & ~(THREAD_SIZE - 1)); 94} 95 96/* thread information allocation */ 97#ifdef CONFIG_DEBUG_STACK_USAGE 98#define alloc_thread_info(tsk) ((struct thread_info *) \ 99 __get_free_pages(GFP_KERNEL| __GFP_ZERO, get_order(THREAD_SIZE))) 100#else 101#define alloc_thread_info(tsk) ((struct thread_info *) \ 102 __get_free_pages(GFP_KERNEL, get_order(THREAD_SIZE))) 103#endif 104 105#define free_thread_info(info) free_pages((unsigned long)(info), get_order(THREAD_SIZE)) 106 107#else /* !__ASSEMBLY__ */ 108 109/* how to get the thread information struct from ASM */ 110#define GET_THREAD_INFO(reg) \ 111 movl $-THREAD_SIZE, reg; \ 112 andl %esp, reg 113 114/* use this one if reg already contains %esp */ 115#define GET_THREAD_INFO_WITH_ESP(reg) \ 116 andl $-THREAD_SIZE, reg 117 118#endif 119 120/* 121 * thread information flags 122 * - these are process state flags that various assembly files may need to access 123 * - pending work-to-be-done flags are in LSW 124 * - other flags in MSW 125 */ 126#define TIF_SYSCALL_TRACE 0 /* syscall trace active */ 127#define TIF_NOTIFY_RESUME 1 /* resumption notification requested */ 128#define TIF_SIGPENDING 2 /* signal pending */ 129#define TIF_NEED_RESCHED 3 /* rescheduling necessary */ 130#define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */ 131#define TIF_IRET 5 /* return with iret */ 132#define TIF_SYSCALL_EMU 6 /* syscall emulation active */ 133#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ 134#define TIF_SECCOMP 8 /* secure computing */ 135#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */ 136#define TIF_MEMDIE 16 137#define TIF_DEBUG 17 /* uses debug registers */ 138#define TIF_IO_BITMAP 18 /* uses I/O bitmap */ 139#define TIF_FREEZE 19 /* is freezing for suspend */ 140 141#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE) 142#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME) 143#define _TIF_SIGPENDING (1<<TIF_SIGPENDING) 144#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED) 145#define _TIF_SINGLESTEP (1<<TIF_SINGLESTEP) 146#define _TIF_IRET (1<<TIF_IRET) 147#define _TIF_SYSCALL_EMU (1<<TIF_SYSCALL_EMU) 148#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT) 149#define _TIF_SECCOMP (1<<TIF_SECCOMP) 150#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK) 151#define _TIF_DEBUG (1<<TIF_DEBUG) 152#define _TIF_IO_BITMAP (1<<TIF_IO_BITMAP) 153#define _TIF_FREEZE (1<<TIF_FREEZE) 154 155/* work to do on interrupt/exception return */ 156#define _TIF_WORK_MASK \ 157 (0x0000FFFF & ~(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ 158 _TIF_SECCOMP | _TIF_SYSCALL_EMU)) 159/* work to do on any return to u-space */ 160#define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP) 161 162/* flags to check in __switch_to() */ 163#define _TIF_WORK_CTXSW (_TIF_DEBUG|_TIF_IO_BITMAP) 164 165/* 166 * Thread-synchronous status. 167 * 168 * This is different from the flags in that nobody else 169 * ever touches our thread-synchronous status, so we don't 170 * have to worry about atomic accesses. 171 */ 172#define TS_USEDFPU 0x0001 /* FPU was used by this task this quantum (SMP) */ 173#define TS_POLLING 0x0002 /* True if in idle loop and not sleeping */ 174 175#define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING) 176 177#endif /* __KERNEL__ */ 178 179#endif /* _ASM_THREAD_INFO_H */ 180