3ae36655b9
There are three choices: vsyscall=native: Vsyscalls are native code that issues the corresponding syscalls. vsyscall=emulate (default): Vsyscalls are emulated by instruction fault traps, tested in the bad_area path. The actual contents of the vsyscall page is the same as the vsyscall=native case except that it's marked NX. This way programs that make assumptions about what the code in the page does will not be confused when they read that code. vsyscall=none: Trying to execute a vsyscall will segfault. Signed-off-by: Andy Lutomirski <luto@mit.edu> Link: http://lkml.kernel.org/r/8449fb3abf89851fd6b2260972666a6f82542284.1312988155.git.luto@mit.edu Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
39 lines
803 B
C
39 lines
803 B
C
#ifndef _ASM_X86_VSYSCALL_H
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#define _ASM_X86_VSYSCALL_H
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enum vsyscall_num {
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__NR_vgettimeofday,
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__NR_vtime,
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__NR_vgetcpu,
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};
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#define VSYSCALL_START (-10UL << 20)
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#define VSYSCALL_SIZE 1024
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#define VSYSCALL_END (-2UL << 20)
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#define VSYSCALL_MAPPED_PAGES 1
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#define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
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#ifdef __KERNEL__
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#include <linux/seqlock.h>
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#define VGETCPU_RDTSCP 1
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#define VGETCPU_LSL 2
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/* kernel space (writeable) */
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extern int vgetcpu_mode;
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extern struct timezone sys_tz;
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#include <asm/vvar.h>
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extern void map_vsyscall(void);
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/*
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* Called on instruction fetch fault in vsyscall page.
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* Returns true if handled.
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*/
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extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address);
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_VSYSCALL_H */
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