• Pavel Emelyanov's avatar
    x86: fix hpet timer reinit for x86_64 · a6a95406
    Pavel Emelyanov authored
    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: default avatarKirill Korotaev <dev@openvz.org>
    Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    a6a95406
hpet.c 25.2 KB