Release 4.8 arch/x86/include/asm/thread_info.h
/* 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);
}
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| Total | 24 | 100.00% | 3 | 100.00% |
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;
}
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| Total | 26 | 100.00% | 1 | 100.00% |
/*
* 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
}
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| Total | 131 | 100.00% | 1 | 100.00% |
#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;
}
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/*
* 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 */
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| Person | Tokens | Prop | Commits | CommitProp |
| christoph lameter | christoph lameter | 224 | 34.36% | 7 | 14.00% |
| kees cook | kees cook | 132 | 20.25% | 1 | 2.00% |
| andy lutomirski | andy lutomirski | 59 | 9.05% | 8 | 16.00% |
| srikar dronamraju | srikar dronamraju | 45 | 6.90% | 2 | 4.00% |
| suresh siddha | suresh siddha | 31 | 4.75% | 1 | 2.00% |
| h. peter anvin | h. peter anvin | 22 | 3.37% | 3 | 6.00% |
| peter zijlstra | peter zijlstra | 19 | 2.91% | 2 | 4.00% |
| brian gerst | brian gerst | 18 | 2.76% | 2 | 4.00% |
| thomas gleixner | thomas gleixner | 18 | 2.76% | 2 | 4.00% |
| frederic weisbecker | frederic weisbecker | 16 | 2.45% | 3 | 6.00% |
| roland mcgrath | roland mcgrath | 13 | 1.99% | 2 | 4.00% |
| jeremy fitzhardinge | jeremy fitzhardinge | 10 | 1.53% | 2 | 4.00% |
| avi kivity | avi kivity | 10 | 1.53% | 1 | 2.00% |
| denys vlasenko | denys vlasenko | 7 | 1.07% | 2 | 4.00% |
| jan beulich | jan beulich | 7 | 1.07% | 1 | 2.00% |
| josh stone | josh stone | 5 | 0.77% | 1 | 2.00% |
| ingo molnar | ingo molnar | 5 | 0.77% | 2 | 4.00% |
| steven rostedt | steven rostedt | 4 | 0.61% | 1 | 2.00% |
| borislav petkov | borislav petkov | 2 | 0.31% | 2 | 4.00% |
| oleg nesterov | oleg nesterov | 1 | 0.15% | 1 | 2.00% |
| andreas dilger | andreas dilger | 1 | 0.15% | 1 | 2.00% |
| arun sharma | arun sharma | 1 | 0.15% | 1 | 2.00% |
| dmitry safonov | dmitry safonov | 1 | 0.15% | 1 | 2.00% |
| joe korty | joe korty | 1 | 0.15% | 1 | 2.00% |
| Total | 652 | 100.00% | 50 | 100.00% |
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