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. */
12 static __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 		WARN_ON_ONCE(flags & (X86_EFLAGS_AC | X86_EFLAGS_DF |
22 				      X86_EFLAGS_NT));
23 
24 		/* We think we came from user mode. Make sure pt_regs agrees. */
25 		WARN_ON_ONCE(!user_mode(regs));
26 
27 		/*
28 		 * All entries from user mode (except #DF) should be on the
29 		 * normal thread stack and should have user pt_regs in the
30 		 * correct location.
31 		 */
32 		WARN_ON_ONCE(!on_thread_stack());
33 		WARN_ON_ONCE(regs != task_pt_regs(current));
34 	}
35 }
36 #define arch_check_user_regs arch_check_user_regs
37 
38 #define ARCH_SYSCALL_EXIT_WORK		(_TIF_SINGLESTEP)
39 
40 static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
41 						  unsigned long ti_work)
42 {
43 	if (ti_work & _TIF_USER_RETURN_NOTIFY)
44 		fire_user_return_notifiers();
45 
46 	if (unlikely(ti_work & _TIF_IO_BITMAP))
47 		tss_update_io_bitmap();
48 
49 	fpregs_assert_state_consistent();
50 	if (unlikely(ti_work & _TIF_NEED_FPU_LOAD))
51 		switch_fpu_return();
52 
53 #ifdef CONFIG_COMPAT
54 	/*
55 	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before
56 	 * returning to user mode.  We need to clear it *after* signal
57 	 * handling, because syscall restart has a fixup for compat
58 	 * syscalls.  The fixup is exercised by the ptrace_syscall_32
59 	 * selftest.
60 	 *
61 	 * We also need to clear TS_REGS_POKED_I386: the 32-bit tracer
62 	 * special case only applies after poking regs and before the
63 	 * very next return to user mode.
64 	 */
65 	current_thread_info()->status &= ~(TS_COMPAT | TS_I386_REGS_POKED);
66 #endif
67 }
68 #define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare
69 
70 static __always_inline void arch_exit_to_user_mode(void)
71 {
72 	mds_user_clear_cpu_buffers();
73 }
74 #define arch_exit_to_user_mode arch_exit_to_user_mode
75 
76 #endif
77