/* SPDX-License-Identifier: GPL-2.0 */ /* thread_info.h: low-level thread information * * Copyright (C) 2002 David Howells (dhowells@redhat.com) * - Incorporating suggestions made by Linus Torvalds and Dave Miller */ #ifndef _ASM_X86_THREAD_INFO_H #define _ASM_X86_THREAD_INFO_H #include <linux/compiler.h> #include <asm/page.h> #include <asm/percpu.h> #include <asm/types.h> /* * TOP_OF_KERNEL_STACK_PADDING is a number of unused bytes that we * reserve at the top of the kernel stack. We do it because of a nasty * 32-bit corner case. On x86_32, the hardware stack frame is * variable-length. Except for vm86 mode, struct pt_regs assumes a * maximum-length frame. If we enter from CPL 0, the top 8 bytes of * pt_regs don't actually exist. Ordinarily this doesn't matter, but it * does in at least one case: * * If we take an NMI early enough in SYSENTER, then we can end up with * pt_regs that extends above sp0. On the way out, in the espfix code, * we can read the saved SS value, but that value will be above sp0. * Without this offset, that can result in a page fault. (We are * careful that, in this case, the value we read doesn't matter.) * * In vm86 mode, the hardware frame is much longer still, so add 16 * bytes to make room for the real-mode segments. * * x86_64 has a fixed-length stack frame. */ #ifdef CONFIG_X86_32 # ifdef CONFIG_VM86 # define TOP_OF_KERNEL_STACK_PADDING 16 # else # define TOP_OF_KERNEL_STACK_PADDING 8 # endif #else # define TOP_OF_KERNEL_STACK_PADDING 0 #endif /* * low level task data that entry.S needs immediate access to * - this struct should fit entirely inside of one cache line * - this struct shares the supervisor stack pages */ #ifndef __ASSEMBLY__ struct task_struct; #include <asm/cpufeature.h> #include <linux/atomic.h> struct thread_info { unsigned long flags; /* low level flags */ u32 status; /* thread synchronous flags */ }; #define INIT_THREAD_INFO(tsk) \ { \ .flags = 0, \ } #else /* !__ASSEMBLY__ */ #include <asm/asm-offsets.h> #endif /* * thread information flags * - these are process state flags that various assembly files * may need to access */ #define TIF_SYSCALL_TRACE 0 /* syscall trace active */ #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ #define TIF_SIGPENDING 2 /* signal pending */ #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ #define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/ #define TIF_SSBD 5 /* Speculative store bypass disable */ #define TIF_SYSCALL_EMU 6 /* syscall emulation active */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SECCOMP 8 /* secure computing */ #define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */ #define TIF_SPEC_FORCE_UPDATE 10 /* Force speculation MSR update in context switch */ #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ #define TIF_UPROBE 12 /* breakpointed or singlestepping */ #define TIF_PATCH_PENDING 13 /* pending live patching update */ #define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */ #define TIF_NOCPUID 15 /* CPUID is not accessible in userland */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* IA32 compatibility process */ #define TIF_NOHZ 19 /* in adaptive nohz mode */ #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ #define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */ #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ #define TIF_FORCED_TF 24 /* true if TF in eflags artificially */ #define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */ #define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */ #define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */ #define TIF_ADDR32 29 /* 32-bit address space on 64 bits */ #define TIF_X32 30 /* 32-bit native x86-64 binary */ #define TIF_FSCHECK 31 /* Check FS is USER_DS on return */ #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) #define _TIF_SSBD (1 << TIF_SSBD) #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_SPEC_IB (1 << TIF_SPEC_IB) #define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE) #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) #define _TIF_UPROBE (1 << TIF_UPROBE) #define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) #define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD) #define _TIF_NOCPUID (1 << TIF_NOCPUID) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) #define _TIF_NOHZ (1 << TIF_NOHZ) #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) #define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP) #define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES) #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) #define _TIF_ADDR32 (1 << TIF_ADDR32) #define _TIF_X32 (1 << TIF_X32) #define _TIF_FSCHECK (1 << TIF_FSCHECK) /* * work to do in syscall_trace_enter(). Also includes TIF_NOHZ for * enter_from_user_mode() */ #define _TIF_WORK_SYSCALL_ENTRY \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \ _TIF_NOHZ) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW_BASE \ (_TIF_IO_BITMAP|_TIF_NOCPUID|_TIF_NOTSC|_TIF_BLOCKSTEP| \ _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE) /* * Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated. */ #ifdef CONFIG_SMP # define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE | _TIF_SPEC_IB) #else # define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE) #endif #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY) #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) #define STACK_WARN (THREAD_SIZE/8) /* * macros/functions for gaining access to the thread information structure * * preempt_count needs to be 1 initially, until the scheduler is functional. */ #ifndef __ASSEMBLY__ /* * Walks up the stack frames to make sure that the specified object is * entirely contained by a single stack frame. * * Returns: * GOOD_FRAME if within a frame * BAD_STACK if placed across a frame boundary (or outside stack) * NOT_STACK unable to determine (no frame pointers, etc) */ static inline int arch_within_stack_frames(const void * const stack, const void * const stackend, const void *obj, unsigned long len) { #if defined(CONFIG_FRAME_POINTER) const void *frame = NULL; const void *oldframe; oldframe = __builtin_frame_address(1); if (oldframe) frame = __builtin_frame_address(2); /* * low ----------------------------------------------> high * [saved bp][saved ip][args][local vars][saved bp][saved ip] * ^----------------^ * allow copies only within here */ while (stack <= frame && frame < stackend) { /* * If obj + len extends past the last frame, this * check won't pass and the next frame will be 0, * causing us to bail out and correctly report * the copy as invalid. */ if (obj + len <= frame) return obj >= oldframe + 2 * sizeof(void *) ? GOOD_FRAME : BAD_STACK; oldframe = frame; frame = *(const void * const *)frame; } return BAD_STACK; #else return NOT_STACK; #endif } #else /* !__ASSEMBLY__ */ #ifdef CONFIG_X86_64 # define cpu_current_top_of_stack (cpu_tss_rw + TSS_sp1) #endif #endif #ifdef CONFIG_COMPAT #define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ #endif #ifndef __ASSEMBLY__ #ifdef CONFIG_X86_32 #define in_ia32_syscall() true #else #define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \ current_thread_info()->status & TS_COMPAT) #endif /* * Force syscall return via IRET by making it look as if there was * some work pending. IRET is our most capable (but slowest) syscall * return path, which is able to restore modified SS, CS and certain * EFLAGS values that other (fast) syscall return instructions * are not able to restore properly. */ #define force_iret() set_thread_flag(TIF_NOTIFY_RESUME) extern void arch_task_cache_init(void); extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); extern void arch_release_task_struct(struct task_struct *tsk); extern void arch_setup_new_exec(void); #define arch_setup_new_exec arch_setup_new_exec #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_THREAD_INFO_H */