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Diffstat (limited to 'arch/x86/include/asm/thread_info.h')
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h new file mode 100644 index 000000000..b5e4c3575 --- /dev/null +++ b/arch/x86/include/asm/thread_info.h @@ -0,0 +1,279 @@ +/* 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_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_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) + +/* work to do on any return to user space */ +#define _TIF_ALLWORK_MASK \ + (_TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \ + _TIF_NEED_RESCHED | _TIF_SINGLESTEP | _TIF_SYSCALL_EMU | \ + _TIF_SYSCALL_AUDIT | _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | \ + _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT | \ + _TIF_FSCHECK) + +/* 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 + +/* + * Thread-synchronous status. + * + * This is different from the flags in that nobody else + * ever touches our thread-synchronous status, so we don't + * have to worry about atomic accesses. + */ +#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ + +#ifndef __ASSEMBLY__ +#ifdef CONFIG_COMPAT +#define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */ +#define TS_COMPAT_RESTART 0x0008 + +#define arch_set_restart_data arch_set_restart_data + +static inline void arch_set_restart_data(struct restart_block *restart) +{ + struct thread_info *ti = current_thread_info(); + if (ti->status & TS_COMPAT) + ti->status |= TS_COMPAT_RESTART; + else + ti->status &= ~TS_COMPAT_RESTART; +} +#endif + +#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 */ |