diff options
Diffstat (limited to 'kernel/arch/x86/include/asm/thread_info.h')
| -rw-r--r-- | kernel/arch/x86/include/asm/thread_info.h | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/kernel/arch/x86/include/asm/thread_info.h b/kernel/arch/x86/include/asm/thread_info.h new file mode 100644 index 000000000..606144afb --- /dev/null +++ b/kernel/arch/x86/include/asm/thread_info.h @@ -0,0 +1,303 @@ +/* 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, 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; +#include <asm/processor.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 */ + int saved_preempt_count; + int preempt_lazy_count; /* 0 => lazy preemptable + <0 => BUG */ + 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, \ + .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 <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_NEED_RESCHED_LAZY 9 /* lazy rescheduling necessary */ +#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_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) +#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_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 _TIF_NEED_RESCHED_MASK (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY) + +#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__ + +DECLARE_PER_CPU(unsigned long, kernel_stack); + +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; +} + +#else /* !__ASSEMBLY__ */ + +/* Load thread_info address into "reg" */ +#define GET_THREAD_INFO(reg) \ + _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \ + _ASM_SUB $(THREAD_SIZE),reg ; + +/* + * 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)*/ +#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; +} + +/* + * 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) + +#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 */ |