From 6e7a333eaa522ef73be01caec7a01521490aaf00 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 22 Jul 2011 09:12:51 +0000 Subject: [PATCH] rtc: Limit RTC PIE frequency The RTC pie hrtimer is self rearming. We really need to limit the frequency to something sensible. Thus limit it to the 8192Hz max value from the rtc man documentation Cc: Willy Tarreau Cc: stable@kernel.org Signed-off-by: Thomas Gleixner [jstultz: slightly reworked to use RTC_MAX_FREQ value] Signed-off-by: John Stultz --- drivers/rtc/interface.c | 2 +- include/linux/rtc.h | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index a1ba2caa8308..44e91e598f8d 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -708,7 +708,7 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) int err = 0; unsigned long flags; - if (freq <= 0) + if (freq <= 0 || freq > RTC_MAX_FREQ) return -EINVAL; retry: spin_lock_irqsave(&rtc->irq_task_lock, flags); diff --git a/include/linux/rtc.h b/include/linux/rtc.h index b27ebea25660..93f4d035076b 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -97,6 +97,9 @@ struct rtc_pll_info { #define RTC_AF 0x20 /* Alarm interrupt */ #define RTC_UF 0x10 /* Update interrupt for 1Hz RTC */ + +#define RTC_MAX_FREQ 8192 + #ifdef __KERNEL__ #include