1 /* thread_info.h: low-level thread information
3 * Copyright (C) 2002 David Howells (dhowells@redhat.com)
4 * - Incorporating suggestions made by Linus Torvalds and Dave Miller
7 #ifndef _ASM_X86_THREAD_INFO_H
8 #define _ASM_X86_THREAD_INFO_H
10 #include <linux/compiler.h>
12 #include <asm/percpu.h>
13 #include <asm/types.h>
16 * TOP_OF_KERNEL_STACK_PADDING is a number of unused bytes that we
17 * reserve at the top of the kernel stack. We do it because of a nasty
18 * 32-bit corner case. On x86_32, the hardware stack frame is
19 * variable-length. Except for vm86 mode, struct pt_regs assumes a
20 * maximum-length frame. If we enter from CPL 0, the top 8 bytes of
21 * pt_regs don't actually exist. Ordinarily this doesn't matter, but it
22 * does in at least one case:
24 * If we take an NMI early enough in SYSENTER, then we can end up with
25 * pt_regs that extends above sp0. On the way out, in the espfix code,
26 * we can read the saved SS value, but that value will be above sp0.
27 * Without this offset, that can result in a page fault. (We are
28 * careful that, in this case, the value we read doesn't matter.)
30 * In vm86 mode, the hardware frame is much longer still, so add 16
31 * bytes to make room for the real-mode segments.
33 * x86_64 has a fixed-length stack frame.
37 # define TOP_OF_KERNEL_STACK_PADDING 16
39 # define TOP_OF_KERNEL_STACK_PADDING 8
42 # define TOP_OF_KERNEL_STACK_PADDING 0
46 * low level task data that entry.S needs immediate access to
47 * - this struct should fit entirely inside of one cache line
48 * - this struct shares the supervisor stack pages
52 #include <asm/cpufeature.h>
53 #include <linux/atomic.h>
55 #define init_stack (init_thread_union.stack)
57 #else /* !__ASSEMBLY__ */
59 #include <asm/asm-offsets.h>
64 * thread information flags
65 * - these are process state flags that various assembly files
67 * - pending work-to-be-done flags are in LSW
68 * - other flags in MSW
69 * Warning: layout of LSW is hardcoded in entry.S
71 #define TIF_SYSCALL_TRACE 0 /* syscall trace active */
72 #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
73 #define TIF_SIGPENDING 2 /* signal pending */
74 #define TIF_NEED_RESCHED 3 /* rescheduling necessary */
75 #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/
76 #define TIF_SYSCALL_EMU 6 /* syscall emulation active */
77 #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
78 #define TIF_SECCOMP 8 /* secure computing */
79 #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
80 #define TIF_UPROBE 12 /* breakpointed or singlestepping */
81 #define TIF_NOTSC 16 /* TSC is not accessible in userland */
82 #define TIF_IA32 17 /* IA32 compatibility process */
83 #define TIF_NOHZ 19 /* in adaptive nohz mode */
84 #define TIF_MEMDIE 20 /* is terminating due to OOM killer */
85 #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
86 #define TIF_IO_BITMAP 22 /* uses I/O bitmap */
87 #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
88 #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
89 #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
90 #define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
91 #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
92 #define TIF_X32 30 /* 32-bit native x86-64 binary */
94 #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
95 #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
96 #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
97 #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
98 #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
99 #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
100 #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
101 #define _TIF_SECCOMP (1 << TIF_SECCOMP)
102 #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
103 #define _TIF_UPROBE (1 << TIF_UPROBE)
104 #define _TIF_NOTSC (1 << TIF_NOTSC)
105 #define _TIF_IA32 (1 << TIF_IA32)
106 #define _TIF_NOHZ (1 << TIF_NOHZ)
107 #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
108 #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
109 #define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
110 #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
111 #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
112 #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
113 #define _TIF_ADDR32 (1 << TIF_ADDR32)
114 #define _TIF_X32 (1 << TIF_X32)
117 * work to do in syscall_trace_enter(). Also includes TIF_NOHZ for
118 * enter_from_user_mode()
120 #define _TIF_WORK_SYSCALL_ENTRY \
121 (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
122 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
125 /* work to do on any return to user space */
126 #define _TIF_ALLWORK_MASK \
127 ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \
130 /* flags to check in __switch_to() */
131 #define _TIF_WORK_CTXSW \
132 (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP)
134 #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
135 #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
137 #define STACK_WARN (THREAD_SIZE/8)
140 * macros/functions for gaining access to the thread information structure
142 * preempt_count needs to be 1 initially, until the scheduler is functional.
146 static inline unsigned long current_stack_pointer(void)
150 asm("mov %%rsp,%0" : "=g" (sp));
152 asm("mov %%esp,%0" : "=g" (sp));
158 * Walks up the stack frames to make sure that the specified object is
159 * entirely contained by a single stack frame.
162 * 1 if within a frame
163 * -1 if placed across a frame boundary (or outside stack)
164 * 0 unable to determine (no frame pointers, etc)
166 static inline int arch_within_stack_frames(const void * const stack,
167 const void * const stackend,
168 const void *obj, unsigned long len)
170 #if defined(CONFIG_FRAME_POINTER)
171 const void *frame = NULL;
172 const void *oldframe;
174 oldframe = __builtin_frame_address(1);
176 frame = __builtin_frame_address(2);
178 * low ----------------------------------------------> high
179 * [saved bp][saved ip][args][local vars][saved bp][saved ip]
181 * allow copies only within here
183 while (stack <= frame && frame < stackend) {
185 * If obj + len extends past the last frame, this
186 * check won't pass and the next frame will be 0,
187 * causing us to bail out and correctly report
188 * the copy as invalid.
190 if (obj + len <= frame)
191 return obj >= oldframe + 2 * sizeof(void *) ? 1 : -1;
193 frame = *(const void * const *)frame;
201 #else /* !__ASSEMBLY__ */
204 # define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
210 #define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */
215 #define in_ia32_syscall() true
217 #define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
218 current->thread.status & TS_COMPAT)
222 * Force syscall return via IRET by making it look as if there was
223 * some work pending. IRET is our most capable (but slowest) syscall
224 * return path, which is able to restore modified SS, CS and certain
225 * EFLAGS values that other (fast) syscall return instructions
226 * are not able to restore properly.
228 #define force_iret() set_thread_flag(TIF_NOTIFY_RESUME)
230 extern void arch_task_cache_init(void);
231 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
232 extern void arch_release_task_struct(struct task_struct *tsk);
233 #endif /* !__ASSEMBLY__ */
235 #endif /* _ASM_X86_THREAD_INFO_H */