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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-17 11:36:10 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-17 11:36:10 -0500
commit2ffbb8377c7a0713baf6644e285adc27a5654582 (patch)
tree055f1fad06e1dba8c2e782786a7cfc2ea448a7f3 /arch/x86/vdso/vgetcpu.c
parent6840999b192b1b57d713ddee3761c457a2779036 (diff)
parent80ef88d6d23bf1b94d65db0ac32334d01b9f7350 (diff)
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86: x86: simplify "make ARCH=x86" and fix kconfig all.config x86: reboot fixup for wrap2c board x86: check boundary in count setup resource x86: fix reboot with no keyboard attached x86: add hpet sanity checks x86: on x86_64, correct reading of PC RTC when update in progress in time_64.c x86: fix freeze in x86_64 RTC update code in time_64.c ntp: fix typo that makes sync_cmos_clock erratic Remove x86 merge artifact from top Makefile x86: fixup cpu_info array conversion x86: show cpuinfo only for online CPUs x86: fix cpu-hotplug regression x86: ignore the sys_getcpu() tcache parameter x86: voyager use correct header file name x86: fix smp init sections x86: fix voyager_cat_init section x86: fix bogus memcpy in es7000_check_dsdt()
Diffstat (limited to 'arch/x86/vdso/vgetcpu.c')
-rw-r--r--arch/x86/vdso/vgetcpu.c19
1 files changed, 2 insertions, 17 deletions
diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c
index 91f6e85d0fc2..3b1ae1abfba9 100644
--- a/arch/x86/vdso/vgetcpu.c
+++ b/arch/x86/vdso/vgetcpu.c
@@ -13,32 +13,17 @@
13#include <asm/vgtod.h> 13#include <asm/vgtod.h>
14#include "vextern.h" 14#include "vextern.h"
15 15
16long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache) 16long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
17{ 17{
18 unsigned int dummy, p; 18 unsigned int dummy, p;
19 unsigned long j = 0;
20 19
21 /* Fast cache - only recompute value once per jiffies and avoid 20 if (*vdso_vgetcpu_mode == VGETCPU_RDTSCP) {
22 relatively costly rdtscp/cpuid otherwise.
23 This works because the scheduler usually keeps the process
24 on the same CPU and this syscall doesn't guarantee its
25 results anyways.
26 We do this here because otherwise user space would do it on
27 its own in a likely inferior way (no access to jiffies).
28 If you don't like it pass NULL. */
29 if (tcache && tcache->blob[0] == (j = *vdso_jiffies)) {
30 p = tcache->blob[1];
31 } else if (*vdso_vgetcpu_mode == VGETCPU_RDTSCP) {
32 /* Load per CPU data from RDTSCP */ 21 /* Load per CPU data from RDTSCP */
33 rdtscp(dummy, dummy, p); 22 rdtscp(dummy, dummy, p);
34 } else { 23 } else {
35 /* Load per CPU data from GDT */ 24 /* Load per CPU data from GDT */
36 asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG)); 25 asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
37 } 26 }
38 if (tcache) {
39 tcache->blob[0] = j;
40 tcache->blob[1] = p;
41 }
42 if (cpu) 27 if (cpu)
43 *cpu = p & 0xfff; 28 *cpu = p & 0xfff;
44 if (node) 29 if (node)