From: David Daney Date: Wed, 19 May 2010 17:40:53 +0000 (-0700) Subject: MIPS: Don't overflow cevt-r4k.c calculations at high clock rates. X-Git-Tag: v2.6.36-rc1~563^2~146 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4d2b11252b92c6aca9f9222ee05e00f7262c2e53;p=karo-tx-linux.git MIPS: Don't overflow cevt-r4k.c calculations at high clock rates. The 'mult' element of struct clock_event_device must never be wider than 32-bits. If it were, it would get truncated when used by clockevent_delta2ns() when this calls do_div(). We can meet this requirement by using clockevent_set_clock() to set the MULT and SHIFT values. Signed-off-by: David Daney Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1253/ Acked-by: Thomas Gleixner Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c index 0b2450ceb13f..2a4d50ff5e2c 100644 --- a/arch/mips/kernel/cevt-r4k.c +++ b/arch/mips/kernel/cevt-r4k.c @@ -163,7 +163,6 @@ int c0_compare_int_usable(void) int __cpuinit r4k_clockevent_init(void) { - uint64_t mips_freq = mips_hpt_frequency; unsigned int cpu = smp_processor_id(); struct clock_event_device *cd; unsigned int irq; @@ -188,9 +187,9 @@ int __cpuinit r4k_clockevent_init(void) cd->name = "MIPS"; cd->features = CLOCK_EVT_FEAT_ONESHOT; + clockevent_set_clock(cd, mips_hpt_frequency); + /* Calculate the min / max delta */ - cd->mult = div_sc((unsigned long) mips_freq, NSEC_PER_SEC, 32); - cd->shift = 32; cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd); cd->min_delta_ns = clockevent_delta2ns(0x300, cd);