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authorAndy Lutomirski <luto@MIT.EDU>2011-05-23 09:31:24 -0400
committerThomas Gleixner <tglx@linutronix.de>2011-05-24 14:51:28 +0200
commit8c49d9a74bac5ea3f18480307057241b808fcc0c (patch)
treea9d2d8160ca37e9292e605cf3cdd85b29646c4b7 /arch/x86/kernel/time.c
parentd762f4383100c2a87b1a3f2d678cd3b5425655b4 (diff)
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/kernel/time.c')
-rw-r--r--arch/x86/kernel/time.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index 25a28a24593..00cbb272627 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -23,7 +23,7 @@
#include <asm/time.h>
#ifdef CONFIG_X86_64
-volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
+DEFINE_VVAR(volatile unsigned long, jiffies) = INITIAL_JIFFIES;
#endif
unsigned long profile_pc(struct pt_regs *regs)