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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
51 static inline unsigned long current_stack_pointer(void)
55 asm("mov %%rsp,%0" : "=g" (sp
));
57 asm("mov %%esp,%0" : "=g" (sp
));
63 #include <asm/cpufeature.h>
64 #include <linux/atomic.h>
67 unsigned long flags
; /* low level flags */
70 #define INIT_THREAD_INFO(tsk) \
75 #define init_stack (init_thread_union.stack)
77 #else /* !__ASSEMBLY__ */
79 #include <asm/asm-offsets.h>
84 * thread information flags
85 * - these are process state flags that various assembly files
88 #define TIF_SYSCALL_TRACE 0 /* syscall trace active */
89 #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
90 #define TIF_SIGPENDING 2 /* signal pending */
91 #define TIF_NEED_RESCHED 3 /* rescheduling necessary */
92 #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/
93 #define TIF_SYSCALL_EMU 6 /* syscall emulation active */
94 #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
95 #define TIF_SECCOMP 8 /* secure computing */
96 #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
97 #define TIF_UPROBE 12 /* breakpointed or singlestepping */
98 #define TIF_PATCH_PENDING 13 /* pending live patching update */
99 #define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
100 #define TIF_NOTSC 16 /* TSC is not accessible in userland */
101 #define TIF_IA32 17 /* IA32 compatibility process */
102 #define TIF_NOHZ 19 /* in adaptive nohz mode */
103 #define TIF_MEMDIE 20 /* is terminating due to OOM killer */
104 #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
105 #define TIF_IO_BITMAP 22 /* uses I/O bitmap */
106 #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
107 #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
108 #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
109 #define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
110 #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
111 #define TIF_X32 30 /* 32-bit native x86-64 binary */
112 #define TIF_FSCHECK 31 /* Check FS is USER_DS on return */
114 #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
115 #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
116 #define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
117 #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
118 #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
119 #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
120 #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
121 #define _TIF_SECCOMP (1 << TIF_SECCOMP)
122 #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
123 #define _TIF_UPROBE (1 << TIF_UPROBE)
124 #define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
125 #define _TIF_NOCPUID (1 << TIF_NOCPUID)
126 #define _TIF_NOTSC (1 << TIF_NOTSC)
127 #define _TIF_IA32 (1 << TIF_IA32)
128 #define _TIF_NOHZ (1 << TIF_NOHZ)
129 #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
130 #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
131 #define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
132 #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
133 #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
134 #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
135 #define _TIF_ADDR32 (1 << TIF_ADDR32)
136 #define _TIF_X32 (1 << TIF_X32)
137 #define _TIF_FSCHECK (1 << TIF_FSCHECK)
140 * work to do in syscall_trace_enter(). Also includes TIF_NOHZ for
141 * enter_from_user_mode()
143 #define _TIF_WORK_SYSCALL_ENTRY \
144 (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
145 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
148 /* work to do on any return to user space */
149 #define _TIF_ALLWORK_MASK \
150 (_TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
151 _TIF_NEED_RESCHED | _TIF_SINGLESTEP | _TIF_SYSCALL_EMU | \
152 _TIF_SYSCALL_AUDIT | _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | \
153 _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT | \
156 /* flags to check in __switch_to() */
157 #define _TIF_WORK_CTXSW \
158 (_TIF_IO_BITMAP|_TIF_NOCPUID|_TIF_NOTSC|_TIF_BLOCKSTEP)
160 #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
161 #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
163 #define STACK_WARN (THREAD_SIZE/8)
166 * macros/functions for gaining access to the thread information structure
168 * preempt_count needs to be 1 initially, until the scheduler is functional.
173 * Walks up the stack frames to make sure that the specified object is
174 * entirely contained by a single stack frame.
177 * GOOD_FRAME if within a frame
178 * BAD_STACK if placed across a frame boundary (or outside stack)
179 * NOT_STACK unable to determine (no frame pointers, etc)
181 static inline int arch_within_stack_frames(const void * const stack
,
182 const void * const stackend
,
183 const void *obj
, unsigned long len
)
185 #if defined(CONFIG_FRAME_POINTER)
186 const void *frame
= NULL
;
187 const void *oldframe
;
189 oldframe
= __builtin_frame_address(1);
191 frame
= __builtin_frame_address(2);
193 * low ----------------------------------------------> high
194 * [saved bp][saved ip][args][local vars][saved bp][saved ip]
196 * allow copies only within here
198 while (stack
<= frame
&& frame
< stackend
) {
200 * If obj + len extends past the last frame, this
201 * check won't pass and the next frame will be 0,
202 * causing us to bail out and correctly report
203 * the copy as invalid.
205 if (obj
+ len
<= frame
)
206 return obj
>= oldframe
+ 2 * sizeof(void *) ?
207 GOOD_FRAME
: BAD_STACK
;
209 frame
= *(const void * const *)frame
;
217 #else /* !__ASSEMBLY__ */
220 # define cpu_current_top_of_stack (cpu_tss_rw + TSS_sp1)
226 #define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */
231 #define in_ia32_syscall() true
233 #define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
234 current->thread.status & TS_COMPAT)
238 * Force syscall return via IRET by making it look as if there was
239 * some work pending. IRET is our most capable (but slowest) syscall
240 * return path, which is able to restore modified SS, CS and certain
241 * EFLAGS values that other (fast) syscall return instructions
242 * are not able to restore properly.
244 #define force_iret() set_thread_flag(TIF_NOTIFY_RESUME)
246 extern void arch_task_cache_init(void);
247 extern int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
);
248 extern void arch_release_task_struct(struct task_struct
*tsk
);
249 extern void arch_setup_new_exec(void);
250 #define arch_setup_new_exec arch_setup_new_exec
251 #endif /* !__ASSEMBLY__ */
253 #endif /* _ASM_X86_THREAD_INFO_H */