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2052e8d4 CL |
1 | /* thread_info.h: low-level thread information |
2 | * | |
3 | * Copyright (C) 2002 David Howells (dhowells@redhat.com) | |
4 | * - Incorporating suggestions made by Linus Torvalds and Dave Miller | |
5 | */ | |
6 | ||
1965aae3 PA |
7 | #ifndef _ASM_X86_THREAD_INFO_H |
8 | #define _ASM_X86_THREAD_INFO_H | |
2052e8d4 | 9 | |
2052e8d4 CL |
10 | #include <linux/compiler.h> |
11 | #include <asm/page.h> | |
198d208d | 12 | #include <asm/percpu.h> |
12a638e1 CL |
13 | #include <asm/types.h> |
14 | ||
3ee4298f AL |
15 | /* |
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: | |
23 | * | |
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.) | |
29 | * | |
5ed92a8a BG |
30 | * In vm86 mode, the hardware frame is much longer still, so add 16 |
31 | * bytes to make room for the real-mode segments. | |
3ee4298f AL |
32 | * |
33 | * x86_64 has a fixed-length stack frame. | |
34 | */ | |
35 | #ifdef CONFIG_X86_32 | |
5ed92a8a BG |
36 | # ifdef CONFIG_VM86 |
37 | # define TOP_OF_KERNEL_STACK_PADDING 16 | |
38 | # else | |
39 | # define TOP_OF_KERNEL_STACK_PADDING 8 | |
40 | # endif | |
3ee4298f AL |
41 | #else |
42 | # define TOP_OF_KERNEL_STACK_PADDING 0 | |
43 | #endif | |
44 | ||
2052e8d4 CL |
45 | /* |
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 | |
2052e8d4 CL |
49 | */ |
50 | #ifndef __ASSEMBLY__ | |
006c484b | 51 | struct task_struct; |
cd4d09ec | 52 | #include <asm/cpufeature.h> |
60063497 | 53 | #include <linux/atomic.h> |
2052e8d4 CL |
54 | |
55 | struct thread_info { | |
56 | struct task_struct *task; /* main task structure */ | |
affa219b | 57 | __u32 flags; /* low level flags */ |
006c484b | 58 | __u32 status; /* thread synchronous flags */ |
2052e8d4 | 59 | __u32 cpu; /* current CPU */ |
2052e8d4 | 60 | }; |
3351cc03 CL |
61 | |
62 | #define INIT_THREAD_INFO(tsk) \ | |
63 | { \ | |
64 | .task = &tsk, \ | |
3351cc03 CL |
65 | .flags = 0, \ |
66 | .cpu = 0, \ | |
3351cc03 CL |
67 | } |
68 | ||
69 | #define init_thread_info (init_thread_union.thread_info) | |
70 | #define init_stack (init_thread_union.stack) | |
71 | ||
2052e8d4 CL |
72 | #else /* !__ASSEMBLY__ */ |
73 | ||
74 | #include <asm/asm-offsets.h> | |
75 | ||
76 | #endif | |
77 | ||
e57549b0 CL |
78 | /* |
79 | * thread information flags | |
80 | * - these are process state flags that various assembly files | |
81 | * may need to access | |
82 | * - pending work-to-be-done flags are in LSW | |
83 | * - other flags in MSW | |
84 | * Warning: layout of LSW is hardcoded in entry.S | |
85 | */ | |
86 | #define TIF_SYSCALL_TRACE 0 /* syscall trace active */ | |
59e52130 | 87 | #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ |
e57549b0 CL |
88 | #define TIF_SIGPENDING 2 /* signal pending */ |
89 | #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ | |
90 | #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ | |
e57549b0 | 91 | #define TIF_SYSCALL_EMU 6 /* syscall emulation active */ |
e57549b0 CL |
92 | #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ |
93 | #define TIF_SECCOMP 8 /* secure computing */ | |
7c68af6e | 94 | #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ |
0326f5a9 | 95 | #define TIF_UPROBE 12 /* breakpointed or singlestepping */ |
e57549b0 | 96 | #define TIF_NOTSC 16 /* TSC is not accessible in userland */ |
6bd33008 | 97 | #define TIF_IA32 17 /* IA32 compatibility process */ |
bf5a3c13 | 98 | #define TIF_NOHZ 19 /* in adaptive nohz mode */ |
0ddc9324 | 99 | #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ |
f80c5b39 | 100 | #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ |
e57549b0 | 101 | #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ |
e57549b0 | 102 | #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */ |
ea8e61b7 | 103 | #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */ |
b407fc57 | 104 | #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */ |
66700001 | 105 | #define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */ |
6bd33008 | 106 | #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */ |
bb212724 | 107 | #define TIF_X32 30 /* 32-bit native x86-64 binary */ |
e57549b0 CL |
108 | |
109 | #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) | |
59e52130 | 110 | #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) |
e57549b0 CL |
111 | #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) |
112 | #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) | |
113 | #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) | |
e57549b0 | 114 | #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU) |
e57549b0 CL |
115 | #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) |
116 | #define _TIF_SECCOMP (1 << TIF_SECCOMP) | |
7c68af6e | 117 | #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) |
0326f5a9 | 118 | #define _TIF_UPROBE (1 << TIF_UPROBE) |
e57549b0 CL |
119 | #define _TIF_NOTSC (1 << TIF_NOTSC) |
120 | #define _TIF_IA32 (1 << TIF_IA32) | |
bf5a3c13 | 121 | #define _TIF_NOHZ (1 << TIF_NOHZ) |
f80c5b39 | 122 | #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) |
e57549b0 | 123 | #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) |
e57549b0 | 124 | #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) |
ea8e61b7 | 125 | #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP) |
b407fc57 | 126 | #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) |
66700001 | 127 | #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) |
6bd33008 | 128 | #define _TIF_ADDR32 (1 << TIF_ADDR32) |
bb212724 | 129 | #define _TIF_X32 (1 << TIF_X32) |
e57549b0 | 130 | |
9999c8c0 AL |
131 | /* |
132 | * work to do in syscall_trace_enter(). Also includes TIF_NOHZ for | |
133 | * enter_from_user_mode() | |
134 | */ | |
d4d67150 | 135 | #define _TIF_WORK_SYSCALL_ENTRY \ |
66700001 | 136 | (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ |
392a6254 | 137 | _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \ |
bf5a3c13 | 138 | _TIF_NOHZ) |
d4d67150 | 139 | |
00c1bb13 | 140 | /* work to do on any return to user space */ |
66700001 | 141 | #define _TIF_ALLWORK_MASK \ |
bf5a3c13 FW |
142 | ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \ |
143 | _TIF_NOHZ) | |
00c1bb13 | 144 | |
00c1bb13 CL |
145 | /* flags to check in __switch_to() */ |
146 | #define _TIF_WORK_CTXSW \ | |
ea8e61b7 | 147 | (_TIF_IO_BITMAP|_TIF_NOTSC|_TIF_BLOCKSTEP) |
00c1bb13 | 148 | |
7c68af6e | 149 | #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY) |
37f07655 | 150 | #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) |
00c1bb13 | 151 | |
198d208d | 152 | #define STACK_WARN (THREAD_SIZE/8) |
b84200b3 | 153 | |
2052e8d4 CL |
154 | /* |
155 | * macros/functions for gaining access to the thread information structure | |
156 | * | |
157 | * preempt_count needs to be 1 initially, until the scheduler is functional. | |
158 | */ | |
159 | #ifndef __ASSEMBLY__ | |
160 | ||
9af45651 | 161 | static inline struct thread_info *current_thread_info(void) |
2052e8d4 | 162 | { |
a7fcf28d | 163 | return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE); |
2052e8d4 CL |
164 | } |
165 | ||
83653c16 AL |
166 | static inline unsigned long current_stack_pointer(void) |
167 | { | |
168 | unsigned long sp; | |
169 | #ifdef CONFIG_X86_64 | |
170 | asm("mov %%rsp,%0" : "=g" (sp)); | |
171 | #else | |
172 | asm("mov %%esp,%0" : "=g" (sp)); | |
173 | #endif | |
174 | return sp; | |
175 | } | |
176 | ||
0f60a8ef KC |
177 | /* |
178 | * Walks up the stack frames to make sure that the specified object is | |
179 | * entirely contained by a single stack frame. | |
180 | * | |
181 | * Returns: | |
182 | * 1 if within a frame | |
183 | * -1 if placed across a frame boundary (or outside stack) | |
184 | * 0 unable to determine (no frame pointers, etc) | |
185 | */ | |
186 | static inline int arch_within_stack_frames(const void * const stack, | |
187 | const void * const stackend, | |
188 | const void *obj, unsigned long len) | |
189 | { | |
190 | #if defined(CONFIG_FRAME_POINTER) | |
191 | const void *frame = NULL; | |
192 | const void *oldframe; | |
193 | ||
194 | oldframe = __builtin_frame_address(1); | |
195 | if (oldframe) | |
196 | frame = __builtin_frame_address(2); | |
197 | /* | |
198 | * low ----------------------------------------------> high | |
199 | * [saved bp][saved ip][args][local vars][saved bp][saved ip] | |
200 | * ^----------------^ | |
201 | * allow copies only within here | |
202 | */ | |
203 | while (stack <= frame && frame < stackend) { | |
204 | /* | |
205 | * If obj + len extends past the last frame, this | |
206 | * check won't pass and the next frame will be 0, | |
207 | * causing us to bail out and correctly report | |
208 | * the copy as invalid. | |
209 | */ | |
210 | if (obj + len <= frame) | |
211 | return obj >= oldframe + 2 * sizeof(void *) ? 1 : -1; | |
212 | oldframe = frame; | |
213 | frame = *(const void * const *)frame; | |
214 | } | |
215 | return -1; | |
216 | #else | |
217 | return 0; | |
218 | #endif | |
219 | } | |
220 | ||
2052e8d4 CL |
221 | #else /* !__ASSEMBLY__ */ |
222 | ||
3a23208e DV |
223 | #ifdef CONFIG_X86_64 |
224 | # define cpu_current_top_of_stack (cpu_tss + TSS_sp0) | |
225 | #endif | |
226 | ||
46db09d3 | 227 | /* |
1ddc6f3c IM |
228 | * ASM operand which evaluates to a 'thread_info' address of |
229 | * the current task, if it is known that "reg" is exactly "off" | |
230 | * bytes below the top of the stack currently. | |
231 | * | |
232 | * ( The kernel stack's size is known at build time, it is usually | |
233 | * 2 or 4 pages, and the bottom of the kernel stack contains | |
234 | * the thread_info structure. So to access the thread_info very | |
235 | * quickly from assembly code we can calculate down from the | |
236 | * top of the kernel stack to the bottom, using constant, | |
237 | * build-time calculations only. ) | |
238 | * | |
239 | * For example, to fetch the current thread_info->flags value into %eax | |
240 | * on x86-64 defconfig kernels, in syscall entry code where RSP is | |
241 | * currently at exactly SIZEOF_PTREGS bytes away from the top of the | |
242 | * stack: | |
243 | * | |
dca5b52a | 244 | * mov ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS), %eax |
1ddc6f3c IM |
245 | * |
246 | * will translate to: | |
247 | * | |
248 | * 8b 84 24 b8 c0 ff ff mov -0x3f48(%rsp), %eax | |
249 | * | |
250 | * which is below the current RSP by almost 16K. | |
46db09d3 | 251 | */ |
dca5b52a | 252 | #define ASM_THREAD_INFO(field, reg, off) ((field)+(off)-THREAD_SIZE)(reg) |
46db09d3 | 253 | |
2052e8d4 CL |
254 | #endif |
255 | ||
2052e8d4 CL |
256 | /* |
257 | * Thread-synchronous status. | |
258 | * | |
259 | * This is different from the flags in that nobody else | |
260 | * ever touches our thread-synchronous status, so we don't | |
261 | * have to worry about atomic accesses. | |
262 | */ | |
f2ea3b1d | 263 | #define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ |
609c19a3 AL |
264 | #ifdef CONFIG_COMPAT |
265 | #define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ | |
266 | #endif | |
2052e8d4 | 267 | |
8a6c160a | 268 | #ifndef __ASSEMBLY__ |
ef334a20 | 269 | |
abfb9498 | 270 | static inline bool in_ia32_syscall(void) |
ef334a20 SD |
271 | { |
272 | #ifdef CONFIG_X86_32 | |
273 | return true; | |
274 | #endif | |
275 | #ifdef CONFIG_IA32_EMULATION | |
276 | if (current_thread_info()->status & TS_COMPAT) | |
277 | return true; | |
278 | #endif | |
279 | return false; | |
280 | } | |
1daeaa31 BG |
281 | |
282 | /* | |
283 | * Force syscall return via IRET by making it look as if there was | |
284 | * some work pending. IRET is our most capable (but slowest) syscall | |
285 | * return path, which is able to restore modified SS, CS and certain | |
286 | * EFLAGS values that other (fast) syscall return instructions | |
287 | * are not able to restore properly. | |
288 | */ | |
289 | #define force_iret() set_thread_flag(TIF_NOTIFY_RESUME) | |
290 | ||
61c4628b | 291 | extern void arch_task_cache_init(void); |
61c4628b | 292 | extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); |
38e7c572 | 293 | extern void arch_release_task_struct(struct task_struct *tsk); |
5f870a3f BP |
294 | #endif /* !__ASSEMBLY__ */ |
295 | ||
1965aae3 | 296 | #endif /* _ASM_X86_THREAD_INFO_H */ |