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__ 52struct task_struct; 53#include <asm/cpufeature.h> 54#include <linux/atomic.h> 55 56struct thread_info { 57 unsigned long flags; /* low level flags */ 58 unsigned long syscall_work; /* SYSCALL_WORK_ flags */ 59 u32 status; /* thread synchronous flags */ 60}; 61 62#define INIT_THREAD_INFO(tsk) \ 63{ \ 64 .flags = 0, \ 65} 66 67#else /* !__ASSEMBLY__ */ 68 69#include <asm/asm-offsets.h> 70 71#endif 72 73/* 74 * thread information flags 75 * - these are process state flags that various assembly files 76 * may need to access 77 */ 78#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ 79#define TIF_SIGPENDING 2 /* signal pending */ 80#define TIF_NEED_RESCHED 3 /* rescheduling necessary */ 81#define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ 82#define TIF_SSBD 5 /* Speculative store bypass disable */ 83#define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */ 84#define TIF_SPEC_L1D_FLUSH 10 /* Flush L1D on mm switches (processes) */ 85#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ 86#define TIF_UPROBE 12 /* breakpointed or singlestepping */ 87#define TIF_PATCH_PENDING 13 /* pending live patching update */ 88#define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */ 89#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */ 90#define TIF_NOTSC 16 /* TSC is not accessible in userland */ 91#define TIF_NOTIFY_SIGNAL 17 /* signal notifications exist */ 92#define TIF_SLD 18 /* Restore split lock detection on context switch */ 93#define TIF_MEMDIE 20 /* is terminating due to OOM killer */ 94#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ 95#define TIF_IO_BITMAP 22 /* uses I/O bitmap */ 96#define TIF_SPEC_FORCE_UPDATE 23 /* Force speculation MSR update in context switch */ 97#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */ 98#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */ 99#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */ 100#define TIF_ADDR32 29 /* 32-bit address space on 64 bits */ 101 102#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) 103#define _TIF_SIGPENDING (1 << TIF_SIGPENDING) 104#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) 105#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) 106#define _TIF_SSBD (1 << TIF_SSBD) 107#define _TIF_SPEC_IB (1 << TIF_SPEC_IB) 108#define _TIF_SPEC_L1D_FLUSH (1 << TIF_SPEC_L1D_FLUSH) 109#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) 110#define _TIF_UPROBE (1 << TIF_UPROBE) 111#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) 112#define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD) 113#define _TIF_NOCPUID (1 << TIF_NOCPUID) 114#define _TIF_NOTSC (1 << TIF_NOTSC) 115#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) 116#define _TIF_SLD (1 << TIF_SLD) 117#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) 118#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) 119#define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE) 120#define _TIF_FORCED_TF (1 << TIF_FORCED_TF) 121#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP) 122#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) 123#define _TIF_ADDR32 (1 << TIF_ADDR32) 124 125/* flags to check in __switch_to() */ 126#define _TIF_WORK_CTXSW_BASE \ 127 (_TIF_NOCPUID | _TIF_NOTSC | _TIF_BLOCKSTEP | \ 128 _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE | _TIF_SLD) 129 130/* 131 * Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated. 132 */ 133#ifdef CONFIG_SMP 134# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE | _TIF_SPEC_IB) 135#else 136# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE) 137#endif 138 139#ifdef CONFIG_X86_IOPL_IOPERM 140# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \ 141 _TIF_IO_BITMAP) 142#else 143# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY) 144#endif 145 146#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) 147 148#define STACK_WARN (THREAD_SIZE/8) 149 150/* 151 * macros/functions for gaining access to the thread information structure 152 * 153 * preempt_count needs to be 1 initially, until the scheduler is functional. 154 */ 155#ifndef __ASSEMBLY__ 156 157/* 158 * Walks up the stack frames to make sure that the specified object is 159 * entirely contained by a single stack frame. 160 * 161 * Returns: 162 * GOOD_FRAME if within a frame 163 * BAD_STACK if placed across a frame boundary (or outside stack) 164 * NOT_STACK unable to determine (no frame pointers, etc) 165 */ 166static inline int arch_within_stack_frames(const void * const stack, 167 const void * const stackend, 168 const void *obj, unsigned long len) 169{ 170#if defined(CONFIG_FRAME_POINTER) 171 const void *frame = NULL; 172 const void *oldframe; 173 174 oldframe = __builtin_frame_address(1); 175 if (oldframe) 176 frame = __builtin_frame_address(2); 177 /* 178 * low ----------------------------------------------> high 179 * [saved bp][saved ip][args][local vars][saved bp][saved ip] 180 * ^----------------^ 181 * allow copies only within here 182 */ 183 while (stack <= frame && frame < stackend) { 184 /* 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. 189 */ 190 if (obj + len <= frame) 191 return obj >= oldframe + 2 * sizeof(void *) ? 192 GOOD_FRAME : BAD_STACK; 193 oldframe = frame; 194 frame = *(const void * const *)frame; 195 } 196 return BAD_STACK; 197#else 198 return NOT_STACK; 199#endif 200} 201 202#endif /* !__ASSEMBLY__ */ 203 204/* 205 * Thread-synchronous status. 206 * 207 * This is different from the flags in that nobody else 208 * ever touches our thread-synchronous status, so we don't 209 * have to worry about atomic accesses. 210 */ 211#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ 212 213#ifndef __ASSEMBLY__ 214#ifdef CONFIG_COMPAT 215#define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ 216 217#define arch_set_restart_data(restart) \ 218 do { restart->arch_data = current_thread_info()->status; } while (0) 219 220#endif 221 222#ifdef CONFIG_X86_32 223#define in_ia32_syscall() true 224#else 225#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \ 226 current_thread_info()->status & TS_COMPAT) 227#endif 228 229extern void arch_task_cache_init(void); 230extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); 231extern void arch_release_task_struct(struct task_struct *tsk); 232extern void arch_setup_new_exec(void); 233#define arch_setup_new_exec arch_setup_new_exec 234#endif /* !__ASSEMBLY__ */ 235 236#endif /* _ASM_X86_THREAD_INFO_H */ 237