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| author | David S. Miller <davem@davemloft.net> | 2008-12-29 05:19:47 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-12-29 05:19:47 +0100 |
| commit | e3c6d4ee545e427b55882d97d3b663c6411645fe (patch) | |
| tree | 294326663fb757739a98083c2ddd570d1eaf7337 /arch/x86/kernel/vsyscall_64.c | |
| parent | sparc: move select of ARCH_SUPPORTS_MSI (diff) | |
| parent | Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/p... (diff) | |
| download | linux-e3c6d4ee545e427b55882d97d3b663c6411645fe.tar.xz linux-e3c6d4ee545e427b55882d97d3b663c6411645fe.zip | |
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
arch/sparc64/kernel/idprom.c
Diffstat (limited to 'arch/x86/kernel/vsyscall_64.c')
| -rw-r--r-- | arch/x86/kernel/vsyscall_64.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 0b8b6690a86d..44153afc9067 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -17,6 +17,9 @@ * want per guest time just set the kernel.vsyscall64 sysctl to 0. */ +/* Disable profiling for userspace code: */ +#define DISABLE_BRANCH_PROFILING + #include <linux/time.h> #include <linux/init.h> #include <linux/kernel.h> @@ -128,7 +131,16 @@ static __always_inline void do_vgettimeofday(struct timeval * tv) gettimeofday(tv,NULL); return; } + + /* + * Surround the RDTSC by barriers, to make sure it's not + * speculated to outside the seqlock critical section and + * does not cause time warps: + */ + rdtsc_barrier(); now = vread(); + rdtsc_barrier(); + base = __vsyscall_gtod_data.clock.cycle_last; mask = __vsyscall_gtod_data.clock.mask; mult = __vsyscall_gtod_data.clock.mult; |