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Diffstat (limited to 'arch/x86/entry/vsyscall/vsyscall_gtod.c')
-rw-r--r--arch/x86/entry/vsyscall/vsyscall_gtod.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/x86/entry/vsyscall/vsyscall_gtod.c b/arch/x86/entry/vsyscall/vsyscall_gtod.c
index 51e330416995..0fb3a104ac62 100644
--- a/arch/x86/entry/vsyscall/vsyscall_gtod.c
+++ b/arch/x86/entry/vsyscall/vsyscall_gtod.c
@@ -16,6 +16,8 @@
#include <asm/vgtod.h>
#include <asm/vvar.h>
+int vclocks_used __read_mostly;
+
DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
void update_vsyscall_tz(void)
@@ -26,12 +28,17 @@ void update_vsyscall_tz(void)
void update_vsyscall(struct timekeeper *tk)
{
+ int vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode;
struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
+ /* Mark the new vclock used. */
+ BUILD_BUG_ON(VCLOCK_MAX >= 32);
+ WRITE_ONCE(vclocks_used, READ_ONCE(vclocks_used) | (1 << vclock_mode));
+
gtod_write_begin(vdata);
/* copy vsyscall data */
- vdata->vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode;
+ vdata->vclock_mode = vclock_mode;
vdata->cycle_last = tk->tkr_mono.cycle_last;
vdata->mask = tk->tkr_mono.mask;
vdata->mult = tk->tkr_mono.mult;