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| author | Andy Lutomirski <luto@MIT.EDU> | 2011-05-23 15:31:24 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-05-24 14:51:28 +0200 |
| commit | 8c49d9a74bac5ea3f18480307057241b808fcc0c (patch) | |
| tree | a9d2d8160ca37e9292e605cf3cdd85b29646c4b7 /arch/x86/vdso/vgetcpu.c | |
| parent | Merge branch 'sh-latest' of git://git.kernel.org/pub/scm/linux/kernel/git/let... (diff) | |
| download | linux-8c49d9a74bac5ea3f18480307057241b808fcc0c.tar.xz linux-8c49d9a74bac5ea3f18480307057241b808fcc0c.zip | |
x86-64: Clean up vdso/kernel shared variables
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>
Diffstat (limited to 'arch/x86/vdso/vgetcpu.c')
| -rw-r--r-- | arch/x86/vdso/vgetcpu.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c index 9fbc6b20026b..5463ad558573 100644 --- a/arch/x86/vdso/vgetcpu.c +++ b/arch/x86/vdso/vgetcpu.c @@ -11,14 +11,13 @@ #include <linux/time.h> #include <asm/vsyscall.h> #include <asm/vgtod.h> -#include "vextern.h" notrace long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused) { unsigned int p; - if (*vdso_vgetcpu_mode == VGETCPU_RDTSCP) { + if (VVAR(vgetcpu_mode) == VGETCPU_RDTSCP) { /* Load per CPU data from RDTSCP */ native_read_tscp(&p); } else { |