| /* 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 <linux/compiler.h> |
| #include <asm/page.h> |
| #include <asm/percpu.h> |
| #include <asm/types.h> |
| |
| /* |
| * 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, so add 16 |
| * bytes to make room for the real-mode segments. |
| * |
| * x86_64 has a fixed-length stack frame. |
| */ |
| #ifdef CONFIG_X86_32 |
| # ifdef CONFIG_VM86 |
| # define TOP_OF_KERNEL_STACK_PADDING 16 |
| # else |
| # define TOP_OF_KERNEL_STACK_PADDING 8 |
| # endif |
| #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; |
| #include <asm/cpufeature.h> |
| #include <linux/atomic.h> |
| |
| struct thread_info { |
| struct task_struct *task; /* main task structure */ |
| __u32 flags; /* low level flags */ |
| __u32 status; /* thread synchronous flags */ |
| __u32 cpu; /* current CPU */ |
| }; |
| |
| #define INIT_THREAD_INFO(tsk) \ |
| { \ |
| .task = &tsk, \ |
| .flags = 0, \ |
| .cpu = 0, \ |
| } |
| |
| #define init_thread_info (init_thread_union.thread_info) |
| #define init_stack (init_thread_union.stack) |
| |
| #else /* !__ASSEMBLY__ */ |
| |
| #include <asm/asm-offsets.h> |
| |
| #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_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_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(). Also includes TIF_NOHZ for |
| * enter_from_user_mode() |
| */ |
| #define _TIF_WORK_SYSCALL_ENTRY \ |
| (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ |
| _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \ |
| _TIF_NOHZ) |
| |
| /* work to do on any return to user space */ |
| #define _TIF_ALLWORK_MASK \ |
| ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \ |
| _TIF_NOHZ) |
| |
| /* 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) |
| |
| /* |
| * macros/functions for gaining access to the thread information structure |
| * |
| * preempt_count needs to be 1 initially, until the scheduler is functional. |
| */ |
| #ifndef __ASSEMBLY__ |
| |
| static inline struct thread_info *current_thread_info(void) |
| { |
| return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE); |
| } |
| |
| static inline unsigned long current_stack_pointer(void) |
| { |
| unsigned long sp; |
| #ifdef CONFIG_X86_64 |
| asm("mov %%rsp,%0" : "=g" (sp)); |
| #else |
| asm("mov %%esp,%0" : "=g" (sp)); |
| #endif |
| return sp; |
| } |
| |
| /* |
| * 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__ */ |
| |
| #ifdef CONFIG_X86_64 |
| # define cpu_current_top_of_stack (cpu_tss + TSS_sp0) |
| #endif |
| |
| /* |
| * ASM operand which evaluates to a 'thread_info' address of |
| * the current task, if it is known that "reg" is exactly "off" |
| * bytes below the top of the stack currently. |
| * |
| * ( The kernel stack's size is known at build time, it is usually |
| * 2 or 4 pages, and the bottom of the kernel stack contains |
| * the thread_info structure. So to access the thread_info very |
| * quickly from assembly code we can calculate down from the |
| * top of the kernel stack to the bottom, using constant, |
| * build-time calculations only. ) |
| * |
| * For example, to fetch the current thread_info->flags value into %eax |
| * on x86-64 defconfig kernels, in syscall entry code where RSP is |
| * currently at exactly SIZEOF_PTREGS bytes away from the top of the |
| * stack: |
| * |
| * mov ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS), %eax |
| * |
| * will translate to: |
| * |
| * 8b 84 24 b8 c0 ff ff mov -0x3f48(%rsp), %eax |
| * |
| * which is below the current RSP by almost 16K. |
| */ |
| #define ASM_THREAD_INFO(field, reg, off) ((field)+(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)*/ |
| #ifdef CONFIG_COMPAT |
| #define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ |
| #endif |
| |
| #ifndef __ASSEMBLY__ |
| |
| static inline bool in_ia32_syscall(void) |
| { |
| #ifdef CONFIG_X86_32 |
| return true; |
| #endif |
| #ifdef CONFIG_IA32_EMULATION |
| if (current_thread_info()->status & TS_COMPAT) |
| return true; |
| #endif |
| return false; |
| } |
| |
| /* |
| * Force syscall return via IRET by making it look as if there was |
| * some work pending. IRET is our most capable (but slowest) syscall |
| * return path, which is able to restore modified SS, CS and certain |
| * EFLAGS values that other (fast) syscall return instructions |
| * are not able to restore properly. |
| */ |
| #define force_iret() set_thread_flag(TIF_NOTIFY_RESUME) |
| |
| 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 /* !__ASSEMBLY__ */ |
| |
| #endif /* _ASM_X86_THREAD_INFO_H */ |