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>
38 lines
597 B
ArmAsm
38 lines
597 B
ArmAsm
/*
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* vsyscall_emu_64.S: Vsyscall emulation page
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*
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* Copyright (c) 2011 Andy Lutomirski
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*
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* Subject to the GNU General Public License, version 2
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*/
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#include <linux/linkage.h>
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#include <asm/irq_vectors.h>
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#include <asm/page_types.h>
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#include <asm/unistd_64.h>
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__PAGE_ALIGNED_DATA
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.globl __vsyscall_page
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.balign PAGE_SIZE, 0xcc
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.type __vsyscall_page, @object
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__vsyscall_page:
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mov $__NR_gettimeofday, %rax
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syscall
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ret
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.balign 1024, 0xcc
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mov $__NR_time, %rax
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syscall
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ret
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.balign 1024, 0xcc
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mov $__NR_getcpu, %rax
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syscall
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ret
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.balign 4096, 0xcc
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.size __vsyscall_page, 4096
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