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authorPavel Emelyanov <xemul@openvz.org>2009-02-04 05:40:31 -0500
committerIngo Molnar <mingo@elte.hu>2009-02-04 19:04:16 -0500
commita6a95406c676ffe4f9dee708eb404a17c69f7fdd (patch)
treed38f5d1e266024e6df16f5499609ab8711b71d27 /arch
parentb1792e367053968f2ddb48bc911d314143ce6242 (diff)
x86: fix hpet timer reinit for x86_64
There's a small problem with hpet_rtc_reinit function - it checks for the: hpet_readl(HPET_COUNTER) - hpet_t1_cmp > 0 to continue increasing both the HPET_T1_CMP (register) and the hpet_t1_cmp (variable). But since the HPET_COUNTER is always 32-bit, if the hpet_t1_cmp is 64-bit this condition will always be FALSE once the latter hits the 32-bit boundary, and we can have a situation, when we don't increase the HPET_T1_CMP register high enough. The result - timer stops ticking, since HPET_T1_CMP becomes less, than the COUNTER and never increased again. The solution is (based on Linus's suggestion) to not compare 64-bits (on 64-bit x86), but to do the comparison on 32-bit signed integers. Reported-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/hpet.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 64d5ad0b8add..c761f914430a 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -1075,7 +1075,7 @@ static void hpet_rtc_timer_reinit(void)
1075 hpet_t1_cmp += delta; 1075 hpet_t1_cmp += delta;
1076 hpet_writel(hpet_t1_cmp, HPET_T1_CMP); 1076 hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
1077 lost_ints++; 1077 lost_ints++;
1078 } while ((long)(hpet_readl(HPET_COUNTER) - hpet_t1_cmp) > 0); 1078 } while ((s32)(hpet_readl(HPET_COUNTER) - hpet_t1_cmp) > 0);
1079 1079
1080 if (lost_ints) { 1080 if (lost_ints) {
1081 if (hpet_rtc_flags & RTC_PIE) 1081 if (hpet_rtc_flags & RTC_PIE)