1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_VSYSCALL_H
3 #define _ASM_X86_VSYSCALL_H
4
5 #include <linux/seqlock.h>
6 #include <uapi/asm/vsyscall.h>
7 #include <asm/page_types.h>
8
9 #ifdef CONFIG_X86_VSYSCALL_EMULATION
10 extern void map_vsyscall(void);
11 extern void set_vsyscall_pgtable_user_bits(pgd_t *root);
12
13 /*
14 * Called on instruction fetch fault in vsyscall page.
15 * Returns true if handled.
16 */
17 extern bool emulate_vsyscall(unsigned long error_code,
18 struct pt_regs *regs, unsigned long address);
19 #else
20 static inline void map_vsyscall(void) {}
21 static inline bool emulate_vsyscall(unsigned long error_code,
22 struct pt_regs *regs, unsigned long address)
23 {
24 return false;
25 }
26 #endif
27
28 /*
29 * The (legacy) vsyscall page is the long page in the kernel portion
30 * of the address space that has user-accessible permissions.
31 */
32 static inline bool is_vsyscall_vaddr(unsigned long vaddr)
33 {
34 return unlikely((vaddr & PAGE_MASK) == VSYSCALL_ADDR);
35 }
36
37 #endif /* _ASM_X86_VSYSCALL_H */
38
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