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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>
31 lines
705 B
ArmAsm
31 lines
705 B
ArmAsm
/*
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* Linker script for 64-bit vDSO.
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* We #include the file to define the layout details.
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* Here we only choose the prelinked virtual address.
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*
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* This file defines the version script giving the user-exported symbols in
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* the DSO. We can define local symbols here called VDSO* to make their
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* values visible using the asm-x86/vdso.h macros from the kernel proper.
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*/
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#define VDSO_PRELINK 0xffffffffff700000
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#include "vdso-layout.lds.S"
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/*
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* This controls what userland symbols we export from the vDSO.
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*/
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VERSION {
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LINUX_2.6 {
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global:
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clock_gettime;
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__vdso_clock_gettime;
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gettimeofday;
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__vdso_gettimeofday;
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getcpu;
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__vdso_getcpu;
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local: *;
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};
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}
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VDSO64_PRELINK = VDSO_PRELINK;
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