/* thread_info.h: low-level thread information * * Copyright (C) 2002 David Howells (dhowells@redhat.com) * - Incorporating suggestions made by Linus Torvalds and Dave Miller */ #ifndef _ASM_X86_THREAD_INFO_H #define _ASM_X86_THREAD_INFO_H #include #include #include #include /* * TOP_OF_KERNEL_STACK_PADDING is a number of unused bytes that we * reserve at the top of the kernel stack. We do it because of a nasty * 32-bit corner case. On x86_32, the hardware stack frame is * variable-length. Except for vm86 mode, struct pt_regs assumes a * maximum-length frame. If we enter from CPL 0, the top 8 bytes of * pt_regs don't actually exist. Ordinarily this doesn't matter, but it * does in at least one case: * * If we take an NMI early enough in SYSENTER, then we can end up with * pt_regs that extends above sp0. On the way out, in the espfix code, * we can read the saved SS value, but that value will be above sp0. * Without this offset, that can result in a page fault. (We are * careful that, in this case, the value we read doesn't matter.) * * In vm86 mode, the hardware frame is much longer still, but we neither * access the extra members from NMI context, nor do we write such a * frame at sp0 at all. * * x86_64 has a fixed-length stack frame. */ #ifdef CONFIG_X86_32 # define TOP_OF_KERNEL_STACK_PADDING 8 #else # define TOP_OF_KERNEL_STACK_PADDING 0 #endif /* * low level task data that entry.S needs immediate access to * - this struct should fit entirely inside of one cache line * - this struct shares the supervisor stack pages */ #ifndef __ASSEMBLY__ struct task_struct; struct exec_domain; #include #include struct thread_info { struct task_struct *task; /* main task structure */ struct exec_domain *exec_domain; /* execution domain */ __u32 flags; /* low level flags */ __u32 status; /* thread synchronous flags */ __u32 cpu; /* current CPU */ int saved_preempt_count; mm_segment_t addr_limit; void __user *sysenter_return; unsigned int sig_on_uaccess_error:1; unsigned int uaccess_err:1; /* uaccess failed */ }; #define INIT_THREAD_INFO(tsk) \ { \ .task = &tsk, \ .exec_domain = &default_exec_domain, \ .flags = 0, \ .cpu = 0, \ .saved_preempt_count = INIT_PREEMPT_COUNT, \ .addr_limit = KERNEL_DS, \ } #define init_thread_info (init_thread_union.thread_info) #define init_stack (init_thread_union.stack) #else /* !__ASSEMBLY__ */ #include #endif /* * thread information flags * - these are process state flags that various assembly files * may need to access * - pending work-to-be-done flags are in LSW * - other flags in MSW * Warning: layout of LSW is hardcoded in entry.S */ #define TIF_SYSCALL_TRACE 0 /* syscall trace active */ #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ #define TIF_SIGPENDING 2 /* signal pending */ #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ #define TIF_SYSCALL_EMU 6 /* syscall emulation active */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SECCOMP 8 /* secure computing */ #define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */ #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ #define TIF_UPROBE 12 /* breakpointed or singlestepping */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* IA32 compatibility process */ #define TIF_FORK 18 /* ret_from_fork */ #define TIF_NOHZ 19 /* in adaptive nohz mode */ #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */ #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */ #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */ #define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */ #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */ #define TIF_X32 30 /* 32-bit native x86-64 binary */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY) #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) #define _TIF_UPROBE (1 << TIF_UPROBE) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) #define _TIF_FORK (1 << TIF_FORK) #define _TIF_NOHZ (1 << TIF_NOHZ) #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP) #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) #define _TIF_ADDR32 (1 << TIF_ADDR32) #define _TIF_X32 (1 << TIF_X32) /* work to do in syscall_trace_enter() */ #define _TIF_WORK_SYSCALL_ENTRY \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT | \ _TIF_NOHZ) /* work to do in syscall_trace_leave() */ #define _TIF_WORK_SYSCALL_EXIT \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP | \ _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ) /* work to do on interrupt/exception return */ #define _TIF_WORK_MASK \ (0x0000FFFF & \ ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT| \ _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU)) /* work to do on any return to user space */ #define _TIF_ALLWORK_MASK \ ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \ _TIF_NOHZ) /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ (_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME | \ _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP) #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY) #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) #define STACK_WARN (THREAD_SIZE/8) #define KERNEL_STACK_OFFSET (5*(BITS_PER_LONG/8)) /* * macros/functions for gaining access to the thread information structure * * preempt_count needs to be 1 initially, until the scheduler is functional. */ #ifndef __ASSEMBLY__ DECLARE_PER_CPU(unsigned long, kernel_stack); static inline struct thread_info *current_thread_info(void) { struct thread_info *ti; ti = (void *)(this_cpu_read_stable(kernel_stack) + KERNEL_STACK_OFFSET - THREAD_SIZE); return ti; } /* * Walks up the stack frames to make sure that the specified object is * entirely contained by a single stack frame. * * Returns: * 1 if within a frame * -1 if placed across a frame boundary (or outside stack) * 0 unable to determine (no frame pointers, etc) */ static inline int arch_within_stack_frames(const void * const stack, const void * const stackend, const void *obj, unsigned long len) { #if defined(CONFIG_FRAME_POINTER) const void *frame = NULL; const void *oldframe; oldframe = __builtin_frame_address(1); if (oldframe) frame = __builtin_frame_address(2); /* * low ----------------------------------------------> high * [saved bp][saved ip][args][local vars][saved bp][saved ip] * ^----------------^ * allow copies only within here */ while (stack <= frame && frame < stackend) { /* * If obj + len extends past the last frame, this * check won't pass and the next frame will be 0, * causing us to bail out and correctly report * the copy as invalid. */ if (obj + len <= frame) return obj >= oldframe + 2 * sizeof(void *) ? 1 : -1; oldframe = frame; frame = *(const void * const *)frame; } return -1; #else return 0; #endif } #else /* !__ASSEMBLY__ */ /* how to get the thread information struct from ASM */ #define GET_THREAD_INFO(reg) \ _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \ _ASM_SUB $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg ; /* * Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in * a certain register (to be used in assembler memory operands). */ #define THREAD_INFO(reg, off) KERNEL_STACK_OFFSET+(off)-THREAD_SIZE(reg) #endif /* * Thread-synchronous status. * * This is different from the flags in that nobody else * ever touches our thread-synchronous status, so we don't * have to worry about atomic accesses. */ #define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ #define TS_RESTORE_SIGMASK 0x0008 /* restore signal mask in do_signal() */ #ifndef __ASSEMBLY__ #define HAVE_SET_RESTORE_SIGMASK 1 static inline void set_restore_sigmask(void) { struct thread_info *ti = current_thread_info(); ti->status |= TS_RESTORE_SIGMASK; WARN_ON(!test_bit(TIF_SIGPENDING, (unsigned long *)&ti->flags)); } static inline void clear_restore_sigmask(void) { current_thread_info()->status &= ~TS_RESTORE_SIGMASK; } static inline bool test_restore_sigmask(void) { return current_thread_info()->status & TS_RESTORE_SIGMASK; } static inline bool test_and_clear_restore_sigmask(void) { struct thread_info *ti = current_thread_info(); if (!(ti->status & TS_RESTORE_SIGMASK)) return false; ti->status &= ~TS_RESTORE_SIGMASK; return true; } static inline bool is_ia32_task(void) { #ifdef CONFIG_X86_32 return true; #endif #ifdef CONFIG_IA32_EMULATION if (current_thread_info()->status & TS_COMPAT) return true; #endif return false; } #endif /* !__ASSEMBLY__ */ #ifndef __ASSEMBLY__ extern void arch_task_cache_init(void); extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); extern void arch_release_task_struct(struct task_struct *tsk); #endif #endif /* _ASM_X86_THREAD_INFO_H */