[linux-2.6-block.git] / arch / x86 / include / asm / thread_info.h

/* 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, but it depends on whether
 * or not FRED is enabled. Future versions of FRED might make this
 * dynamic, but for now it is always 2 words longer.
 */
#ifdef CONFIG_X86_32
# ifdef CONFIG_VM86
#  define TOP_OF_KERNEL_STACK_PADDING 16
# else
#  define TOP_OF_KERNEL_STACK_PADDING 8
# endif
#else /* x86-64 */
# ifdef CONFIG_X86_FRED
#  define TOP_OF_KERNEL_STACK_PADDING (2 * 8)
# else
#  define TOP_OF_KERNEL_STACK_PADDING 0
# endif
#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 __ASSEMBLER__
struct task_struct;
#include <asm/cpufeature.h>
#include <linux/atomic.h>

struct thread_info {
	unsigned long		flags;		/* low level flags */
	unsigned long		syscall_work;	/* SYSCALL_WORK_ flags */
	u32			status;		/* thread synchronous flags */
#ifdef CONFIG_SMP
	u32			cpu;		/* current CPU */
#endif
};

#define INIT_THREAD_INFO(tsk)			\
{						\
	.flags		= 0,			\
}

#else /* !__ASSEMBLER__ */

#include <asm/asm-offsets.h>

#endif

/*
 * thread information flags
 * - these are process state flags that various assembly files
 *   may need to access
 */
#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_NEED_RESCHED_LAZY	4	/* Lazy rescheduling needed */
#define TIF_SINGLESTEP		5	/* reenable singlestep on user return*/
#define TIF_SSBD		6	/* Speculative store bypass disable */
#define TIF_SPEC_IB		9	/* Indirect branch speculation mitigation */
#define TIF_SPEC_L1D_FLUSH	10	/* Flush L1D on mm switches (processes) */
#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_NOTIFY_SIGNAL	17	/* signal notifications exist */
#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_SPEC_FORCE_UPDATE	23	/* Force speculation MSR update in context switch */
#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_ADDR32		29	/* 32-bit address space on 64 bits */

#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
#define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
#define _TIF_SSBD		(1 << TIF_SSBD)
#define _TIF_SPEC_IB		(1 << TIF_SPEC_IB)
#define _TIF_SPEC_L1D_FLUSH	(1 << TIF_SPEC_L1D_FLUSH)
#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_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
#define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
#define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)
#define _TIF_SPEC_FORCE_UPDATE	(1 << TIF_SPEC_FORCE_UPDATE)
#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_ADDR32		(1 << TIF_ADDR32)

/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW_BASE					\
	(_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

#ifdef CONFIG_X86_IOPL_IOPERM
# define _TIF_WORK_CTXSW_PREV	(_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \
				 _TIF_IO_BITMAP)
#else
# define _TIF_WORK_CTXSW_PREV	(_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY)
#endif

#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 __ASSEMBLER__

/*
 * 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)
 *
 * This function reads pointers from the stack and dereferences them. The
 * pointers may not have their KMSAN shadow set up properly, which may result
 * in false positive reports. Disable instrumentation to avoid those.
 */
__no_kmsan_checks
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
}

#endif  /* !__ASSEMBLER__ */

/*
 * 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 __ASSEMBLER__
#ifdef CONFIG_COMPAT
#define TS_I386_REGS_POKED	0x0004	/* regs poked by 32-bit ptracer */

#define arch_set_restart_data(restart)	\
	do { restart->arch_data = current_thread_info()->status; } while (0)

#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

extern void arch_setup_new_exec(void);
#define arch_setup_new_exec arch_setup_new_exec
#endif	/* !__ASSEMBLER__ */

#endif /* _ASM_X86_THREAD_INFO_H */
Commit	Line	Data
	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, but it depends on whether
	35	* or not FRED is enabled. Future versions of FRED might make this
	36	* dynamic, but for now it is always 2 words longer.
	37	*/
	38	#ifdef CONFIG_X86_32
	39	# ifdef CONFIG_VM86
	40	# define TOP_OF_KERNEL_STACK_PADDING 16
	41	# else
	42	# define TOP_OF_KERNEL_STACK_PADDING 8
	43	# endif
	44	#else /* x86-64 */
	45	# ifdef CONFIG_X86_FRED
	46	# define TOP_OF_KERNEL_STACK_PADDING (2 * 8)
	47	# else
	48	# define TOP_OF_KERNEL_STACK_PADDING 0
	49	# endif
	50	#endif
	51
	52	/*
	53	* low level task data that entry.S needs immediate access to
	54	* - this struct should fit entirely inside of one cache line
	55	* - this struct shares the supervisor stack pages
	56	*/
	57	#ifndef __ASSEMBLER__
	58	struct task_struct;
	59	#include <asm/cpufeature.h>
	60	#include <linux/atomic.h>
	61
	62	struct thread_info {
	63	unsigned long flags; /* low level flags */
	64	unsigned long syscall_work; /* SYSCALL_WORK_ flags */
	65	u32 status; /* thread synchronous flags */
	66	#ifdef CONFIG_SMP
	67	u32 cpu; /* current CPU */
	68	#endif
	69	};
	70
	71	#define INIT_THREAD_INFO(tsk) \
	72	{ \
	73	.flags = 0, \
	74	}
	75
	76	#else /* !__ASSEMBLER__ */
	77
	78	#include <asm/asm-offsets.h>
	79
	80	#endif
	81
	82	/*
	83	* thread information flags
	84	* - these are process state flags that various assembly files
	85	* may need to access
	86	*/
	87	#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
	88	#define TIF_SIGPENDING 2 /* signal pending */
	89	#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
	90	#define TIF_NEED_RESCHED_LAZY 4 /* Lazy rescheduling needed */
	91	#define TIF_SINGLESTEP 5 /* reenable singlestep on user return*/
	92	#define TIF_SSBD 6 /* Speculative store bypass disable */
	93	#define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */
	94	#define TIF_SPEC_L1D_FLUSH 10 /* Flush L1D on mm switches (processes) */
	95	#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
	96	#define TIF_UPROBE 12 /* breakpointed or singlestepping */
	97	#define TIF_PATCH_PENDING 13 /* pending live patching update */
	98	#define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */
	99	#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
	100	#define TIF_NOTSC 16 /* TSC is not accessible in userland */
	101	#define TIF_NOTIFY_SIGNAL 17 /* signal notifications exist */
	102	#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
	103	#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
	104	#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
	105	#define TIF_SPEC_FORCE_UPDATE 23 /* Force speculation MSR update in context switch */
	106	#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
	107	#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
	108	#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
	109	#define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
	110
	111	#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
	112	#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
	113	#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
	114	#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY)
	115	#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
	116	#define _TIF_SSBD (1 << TIF_SSBD)
	117	#define _TIF_SPEC_IB (1 << TIF_SPEC_IB)
	118	#define _TIF_SPEC_L1D_FLUSH (1 << TIF_SPEC_L1D_FLUSH)
	119	#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
	120	#define _TIF_UPROBE (1 << TIF_UPROBE)
	121	#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
	122	#define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD)
	123	#define _TIF_NOCPUID (1 << TIF_NOCPUID)
	124	#define _TIF_NOTSC (1 << TIF_NOTSC)
	125	#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
	126	#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
	127	#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
	128	#define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE)
	129	#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
	130	#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
	131	#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
	132	#define _TIF_ADDR32 (1 << TIF_ADDR32)
	133
	134	/* flags to check in __switch_to() */
	135	#define _TIF_WORK_CTXSW_BASE \
	136	(_TIF_NOCPUID \| _TIF_NOTSC \| _TIF_BLOCKSTEP \| \
	137	_TIF_SSBD \| _TIF_SPEC_FORCE_UPDATE)
	138
	139	/*
	140	* Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated.
	141	*/
	142	#ifdef CONFIG_SMP
	143	# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE \| _TIF_SPEC_IB)
	144	#else
	145	# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE)
	146	#endif
	147
	148	#ifdef CONFIG_X86_IOPL_IOPERM
	149	# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW\| _TIF_USER_RETURN_NOTIFY \| \
	150	_TIF_IO_BITMAP)
	151	#else
	152	# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW\| _TIF_USER_RETURN_NOTIFY)
	153	#endif
	154
	155	#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
	156
	157	#define STACK_WARN (THREAD_SIZE/8)
	158
	159	/*
	160	* macros/functions for gaining access to the thread information structure
	161	*
	162	* preempt_count needs to be 1 initially, until the scheduler is functional.
	163	*/
	164	#ifndef __ASSEMBLER__
	165
	166	/*
	167	* Walks up the stack frames to make sure that the specified object is
	168	* entirely contained by a single stack frame.
	169	*
	170	* Returns:
	171	* GOOD_FRAME if within a frame
	172	* BAD_STACK if placed across a frame boundary (or outside stack)
	173	* NOT_STACK unable to determine (no frame pointers, etc)
	174	*
	175	* This function reads pointers from the stack and dereferences them. The
	176	* pointers may not have their KMSAN shadow set up properly, which may result
	177	* in false positive reports. Disable instrumentation to avoid those.
	178	*/
	179	__no_kmsan_checks
	180	static inline int arch_within_stack_frames(const void * const stack,
	181	const void * const stackend,
	182	const void *obj, unsigned long len)
	183	{
	184	#if defined(CONFIG_FRAME_POINTER)
	185	const void *frame = NULL;
	186	const void *oldframe;
	187
	188	oldframe = __builtin_frame_address(1);
	189	if (oldframe)
	190	frame = __builtin_frame_address(2);
	191	/*
	192	* low ----------------------------------------------> high
	193	* [saved bp][saved ip][args][local vars][saved bp][saved ip]
	194	* ^----------------^
	195	* allow copies only within here
	196	*/
	197	while (stack <= frame && frame < stackend) {
	198	/*
	199	* If obj + len extends past the last frame, this
	200	* check won't pass and the next frame will be 0,
	201	* causing us to bail out and correctly report
	202	* the copy as invalid.
	203	*/
	204	if (obj + len <= frame)
	205	return obj >= oldframe + 2 * sizeof(void *) ?
	206	GOOD_FRAME : BAD_STACK;
	207	oldframe = frame;
	208	frame = (const void const *)frame;
	209	}
	210	return BAD_STACK;
	211	#else
	212	return NOT_STACK;
	213	#endif
	214	}
	215
	216	#endif /* !__ASSEMBLER__ */
	217
	218	/*
	219	* Thread-synchronous status.
	220	*
	221	* This is different from the flags in that nobody else
	222	* ever touches our thread-synchronous status, so we don't
	223	* have to worry about atomic accesses.
	224	*/
	225	#define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/
	226
	227	#ifndef __ASSEMBLER__
	228	#ifdef CONFIG_COMPAT
	229	#define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */
	230
	231	#define arch_set_restart_data(restart) \
	232	do { restart->arch_data = current_thread_info()->status; } while (0)
	233
	234	#endif
	235
	236	#ifdef CONFIG_X86_32
	237	#define in_ia32_syscall() true
	238	#else
	239	#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
	240	current_thread_info()->status & TS_COMPAT)
	241	#endif
	242
	243	extern void arch_setup_new_exec(void);
	244	#define arch_setup_new_exec arch_setup_new_exec
	245	#endif /* !__ASSEMBLER__ */
	246
	247	#endif /* _ASM_X86_THREAD_INFO_H */