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Variables that are shared between the vdso and the kernel are currently a bit of a mess. They are each defined with their own magic, they are accessed differently in the kernel, the vsyscall page, and the vdso, and one of them (vsyscall_clock) doesn't even really exist. This changes them all to use a common mechanism. All of them are delcared in vvar.h with a fixed address (validated by the linker script). In the kernel (as before), they look like ordinary read-write variables. In the vsyscall page and the vdso, they are accessed through a new macro VVAR, which gives read-only access. The vdso is now loaded verbatim into memory without any fixups. As a side bonus, access from the vdso is faster because a level of indirection is removed. While we're at it, pack jiffies and vgetcpu_mode into the same cacheline. Signed-off-by: Andy Lutomirski <luto@mit.edu> Cc: Andi Kleen <andi@firstfloor.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Borislav Petkov <bp@amd64.org> Link: http://lkml.kernel.org/r/%3C7357882fbb51fa30491636a7b6528747301b7ee9.1306156808.git.luto%40mit.edu%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
34 lines
961 B
C
34 lines
961 B
C
#ifndef _ASM_X86_VDSO_H
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#define _ASM_X86_VDSO_H
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#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
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extern const char VDSO32_PRELINK[];
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/*
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* Given a pointer to the vDSO image, find the pointer to VDSO32_name
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* as that symbol is defined in the vDSO sources or linker script.
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*/
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#define VDSO32_SYMBOL(base, name) \
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({ \
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extern const char VDSO32_##name[]; \
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(void *)(VDSO32_##name - VDSO32_PRELINK + (unsigned long)(base)); \
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})
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#endif
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/*
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* These symbols are defined with the addresses in the vsyscall page.
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* See vsyscall-sigreturn.S.
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*/
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extern void __user __kernel_sigreturn;
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extern void __user __kernel_rt_sigreturn;
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/*
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* These symbols are defined by vdso32.S to mark the bounds
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* of the ELF DSO images included therein.
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*/
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extern const char vdso32_int80_start, vdso32_int80_end;
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extern const char vdso32_syscall_start, vdso32_syscall_end;
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extern const char vdso32_sysenter_start, vdso32_sysenter_end;
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#endif /* _ASM_X86_VDSO_H */
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