1/* SPDX-License-Identifier: GPL-2.0-only */
 2#ifndef _ASM_X86_ENTRY_COMMON_H
 3#define _ASM_X86_ENTRY_COMMON_H
 4
 5#include <linux/user-return-notifier.h>
 6
 7#include <asm/nospec-branch.h>
 8#include <asm/io_bitmap.h>
 9#include <asm/fpu/api.h>
10
11/* Check that the stack and regs on entry from user mode are sane. */
12static __always_inline void arch_check_user_regs(struct pt_regs *regs)
13{
14	if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) {
15		/*
16		 * Make sure that the entry code gave us a sensible EFLAGS
17		 * register.  Native because we want to check the actual CPU
18		 * state, not the interrupt state as imagined by Xen.
19		 */
20		unsigned long flags = native_save_fl();
21		unsigned long mask = X86_EFLAGS_DF | X86_EFLAGS_NT;
22
23		/*
24		 * For !SMAP hardware we patch out CLAC on entry.
25		 */
26		if (boot_cpu_has(X86_FEATURE_SMAP) ||
27		    (IS_ENABLED(CONFIG_64_BIT) && boot_cpu_has(X86_FEATURE_XENPV)))
28			mask |= X86_EFLAGS_AC;
29
30		WARN_ON_ONCE(flags & mask);
31
32		/* We think we came from user mode. Make sure pt_regs agrees. */
33		WARN_ON_ONCE(!user_mode(regs));
34
35		/*
36		 * All entries from user mode (except #DF) should be on the
37		 * normal thread stack and should have user pt_regs in the
38		 * correct location.
39		 */
40		WARN_ON_ONCE(!on_thread_stack());
41		WARN_ON_ONCE(regs != task_pt_regs(current));
42	}
43}
44#define arch_check_user_regs arch_check_user_regs
45
46#define ARCH_SYSCALL_EXIT_WORK		(_TIF_SINGLESTEP)
47
48static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
49						  unsigned long ti_work)
50{
51	if (ti_work & _TIF_USER_RETURN_NOTIFY)
52		fire_user_return_notifiers();
53
54	if (unlikely(ti_work & _TIF_IO_BITMAP))
55		tss_update_io_bitmap();
56
57	fpregs_assert_state_consistent();
58	if (unlikely(ti_work & _TIF_NEED_FPU_LOAD))
59		switch_fpu_return();
60
61#ifdef CONFIG_COMPAT
62	/*
63	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before
64	 * returning to user mode.  We need to clear it *after* signal
65	 * handling, because syscall restart has a fixup for compat
66	 * syscalls.  The fixup is exercised by the ptrace_syscall_32
67	 * selftest.
68	 *
69	 * We also need to clear TS_REGS_POKED_I386: the 32-bit tracer
70	 * special case only applies after poking regs and before the
71	 * very next return to user mode.
72	 */
73	current_thread_info()->status &= ~(TS_COMPAT | TS_I386_REGS_POKED);
74#endif
75}
76#define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare
77
78static __always_inline void arch_exit_to_user_mode(void)
79{
80	mds_user_clear_cpu_buffers();
81}
82#define arch_exit_to_user_mode arch_exit_to_user_mode
83
84#endif