1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* thread_info.h: low-level thread information 3 * 4 * Copyright (C) 2002 David Howells (dhowells@redhat.com) 5 * - Incorporating suggestions made by Linus Torvalds and Dave Miller 6 */ 7 8 #ifndef _ASM_X86_THREAD_INFO_H 9 #define _ASM_X86_THREAD_INFO_H 10 11 #include <linux/compiler.h> 12 #include <asm/page.h> 13 #include <asm/percpu.h> 14 #include <asm/types.h> 15 16 /* 17 * TOP_OF_KERNEL_STACK_PADDING is a number of unused bytes that we 18 * reserve at the top of the kernel stack. We do it because of a nasty 19 * 32-bit corner case. On x86_32, the hardware stack frame is 20 * variable-length. Except for vm86 mode, struct pt_regs assumes a 21 * maximum-length frame. If we enter from CPL 0, the top 8 bytes of 22 * pt_regs don't actually exist. Ordinarily this doesn't matter, but it 23 * does in at least one case: 24 * 25 * If we take an NMI early enough in SYSENTER, then we can end up with 26 * pt_regs that extends above sp0. On the way out, in the espfix code, 27 * we can read the saved SS value, but that value will be above sp0. 28 * Without this offset, that can result in a page fault. (We are 29 * careful that, in this case, the value we read doesn't matter.) 30 * 31 * In vm86 mode, the hardware frame is much longer still, so add 16 32 * bytes to make room for the real-mode segments. 33 * 34 * x86_64 has a fixed-length stack frame. 35 */ 36 #ifdef CONFIG_X86_32 37 # ifdef CONFIG_VM86 38 # define TOP_OF_KERNEL_STACK_PADDING 16 39 # else 40 # define TOP_OF_KERNEL_STACK_PADDING 8 41 # endif 42 #else 43 # define TOP_OF_KERNEL_STACK_PADDING 0 44 #endif 45 46 /* 47 * low level task data that entry.S needs immediate access to 48 * - this struct should fit entirely inside of one cache line 49 * - this struct shares the supervisor stack pages 50 */ 51 #ifndef __ASSEMBLY__ 52 struct task_struct; 53 #include <asm/cpufeature.h> 54 #include <linux/atomic.h> 55 56 struct thread_info { 57 unsigned long flags; /* low level flags */ 58 unsigned long syscall_work; /* SYSCALL_WORK_ flags */ 59 u32 status; /* thread synchronous flags */ 60 #ifdef CONFIG_SMP 61 u32 cpu; /* current CPU */ 62 #endif 63 }; 64 65 #define INIT_THREAD_INFO(tsk) \ 66 { \ 67 .flags = 0, \ 68 } 69 70 #else /* !__ASSEMBLY__ */ 71 72 #include <asm/asm-offsets.h> 73 74 #endif 75 76 /* 77 * thread information flags 78 * - these are process state flags that various assembly files 79 * may need to access 80 */ 81 #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ 82 #define TIF_SIGPENDING 2 /* signal pending */ 83 #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ 84 #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ 85 #define TIF_SSBD 5 /* Speculative store bypass disable */ 86 #define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */ 87 #define TIF_SPEC_L1D_FLUSH 10 /* Flush L1D on mm switches (processes) */ 88 #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ 89 #define TIF_UPROBE 12 /* breakpointed or singlestepping */ 90 #define TIF_PATCH_PENDING 13 /* pending live patching update */ 91 #define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */ 92 #define TIF_NOCPUID 15 /* CPUID is not accessible in userland */ 93 #define TIF_NOTSC 16 /* TSC is not accessible in userland */ 94 #define TIF_NOTIFY_SIGNAL 17 /* signal notifications exist */ 95 #define TIF_SLD 18 /* Restore split lock detection on context switch */ 96 #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ 97 #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ 98 #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ 99 #define TIF_SPEC_FORCE_UPDATE 23 /* Force speculation MSR update in context switch */ 100 #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */ 101 #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */ 102 #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */ 103 #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */ 104 105 #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) 106 #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) 107 #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) 108 #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) 109 #define _TIF_SSBD (1 << TIF_SSBD) 110 #define _TIF_SPEC_IB (1 << TIF_SPEC_IB) 111 #define _TIF_SPEC_L1D_FLUSH (1 << TIF_SPEC_L1D_FLUSH) 112 #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) 113 #define _TIF_UPROBE (1 << TIF_UPROBE) 114 #define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) 115 #define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD) 116 #define _TIF_NOCPUID (1 << TIF_NOCPUID) 117 #define _TIF_NOTSC (1 << TIF_NOTSC) 118 #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) 119 #define _TIF_SLD (1 << TIF_SLD) 120 #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) 121 #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) 122 #define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE) 123 #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) 124 #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP) 125 #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) 126 #define _TIF_ADDR32 (1 << TIF_ADDR32) 127 128 /* flags to check in __switch_to() */ 129 #define _TIF_WORK_CTXSW_BASE \ 130 (_TIF_NOCPUID | _TIF_NOTSC | _TIF_BLOCKSTEP | \ 131 _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE | _TIF_SLD) 132 133 /* 134 * Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated. 135 */ 136 #ifdef CONFIG_SMP 137 # define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE | _TIF_SPEC_IB) 138 #else 139 # define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE) 140 #endif 141 142 #ifdef CONFIG_X86_IOPL_IOPERM 143 # define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \ 144 _TIF_IO_BITMAP) 145 #else 146 # define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY) 147 #endif 148 149 #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) 150 151 #define STACK_WARN (THREAD_SIZE/8) 152 153 /* 154 * macros/functions for gaining access to the thread information structure 155 * 156 * preempt_count needs to be 1 initially, until the scheduler is functional. 157 */ 158 #ifndef __ASSEMBLY__ 159 160 /* 161 * Walks up the stack frames to make sure that the specified object is 162 * entirely contained by a single stack frame. 163 * 164 * Returns: 165 * GOOD_FRAME if within a frame 166 * BAD_STACK if placed across a frame boundary (or outside stack) 167 * NOT_STACK unable to determine (no frame pointers, etc) 168 */ 169 static inline int arch_within_stack_frames(const void * const stack, 170 const void * const stackend, 171 const void *obj, unsigned long len) 172 { 173 #if defined(CONFIG_FRAME_POINTER) 174 const void *frame = NULL; 175 const void *oldframe; 176 177 oldframe = __builtin_frame_address(1); 178 if (oldframe) 179 frame = __builtin_frame_address(2); 180 /* 181 * low ----------------------------------------------> high 182 * [saved bp][saved ip][args][local vars][saved bp][saved ip] 183 * ^----------------^ 184 * allow copies only within here 185 */ 186 while (stack <= frame && frame < stackend) { 187 /* 188 * If obj + len extends past the last frame, this 189 * check won't pass and the next frame will be 0, 190 * causing us to bail out and correctly report 191 * the copy as invalid. 192 */ 193 if (obj + len <= frame) 194 return obj >= oldframe + 2 * sizeof(void *) ? 195 GOOD_FRAME : BAD_STACK; 196 oldframe = frame; 197 frame = *(const void * const *)frame; 198 } 199 return BAD_STACK; 200 #else 201 return NOT_STACK; 202 #endif 203 } 204 205 #endif /* !__ASSEMBLY__ */ 206 207 /* 208 * Thread-synchronous status. 209 * 210 * This is different from the flags in that nobody else 211 * ever touches our thread-synchronous status, so we don't 212 * have to worry about atomic accesses. 213 */ 214 #define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ 215 216 #ifndef __ASSEMBLY__ 217 #ifdef CONFIG_COMPAT 218 #define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ 219 220 #define arch_set_restart_data(restart) \ 221 do { restart->arch_data = current_thread_info()->status; } while (0) 222 223 #endif 224 225 #ifdef CONFIG_X86_32 226 #define in_ia32_syscall() true 227 #else 228 #define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \ 229 current_thread_info()->status & TS_COMPAT) 230 #endif 231 232 extern void arch_task_cache_init(void); 233 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); 234 extern void arch_release_task_struct(struct task_struct *tsk); 235 extern void arch_setup_new_exec(void); 236 #define arch_setup_new_exec arch_setup_new_exec 237 #endif /* !__ASSEMBLY__ */ 238 239 #endif /* _ASM_X86_THREAD_INFO_H */ 240