From 2c6221483169ddd4c04797cd7296ed4fe52fcdd7 Mon Sep 17 00:00:00 2001 From: Tony Breeds Date: Thu, 18 Oct 2007 03:04:57 -0700 Subject: Fix discrepancy between VDSO based gettimeofday() and sys_gettimeofday(). On platforms that copy sys_tz into the vdso (currently only x86_64, soon to include powerpc), it is possible for the vdso to get out of sync if a user calls (admittedly unusual) settimeofday(NULL, ptr). This patch adds a hook for architectures that set CONFIG_GENERIC_TIME_VSYSCALL to ensure when sys_tz is updated they can also updatee their copy in the vdso. Signed-off-by: Tony Breeds Cc: Andi Kleen Cc: Tony Luck Acked-by: John Stultz Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/kernel/time.c | 5 +++++ arch/x86/kernel/vsyscall_64.c | 11 ++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 98cfc90cab1d..2bb84214e5f1 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -371,6 +371,11 @@ ia64_setup_printk_clock(void) ia64_printk_clock = ia64_itc_printk_clock; } +/* IA64 doesn't cache the timezone */ +void update_vsyscall_tz(void) +{ +} + void update_vsyscall(struct timespec *wall, struct clocksource *c) { unsigned long flags; diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 8a67e282cb5e..f24e8acdec91 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -64,6 +64,16 @@ struct vsyscall_gtod_data __vsyscall_gtod_data __section_vsyscall_gtod_data = .sysctl_enabled = 1, }; +void update_vsyscall_tz(void) +{ + unsigned long flags; + + write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags); + /* sys_tz has changed */ + vsyscall_gtod_data.sys_tz = sys_tz; + write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags); +} + void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) { unsigned long flags; @@ -77,7 +87,6 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) vsyscall_gtod_data.clock.shift = clock->shift; vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec; vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec; - vsyscall_gtod_data.sys_tz = sys_tz; vsyscall_gtod_data.wall_to_monotonic = wall_to_monotonic; write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags); } -- cgit v1.2.3-59-g8ed1b