Date: Sat, 1 Dec 2012 18:16:14 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r243764 - head/sys/x86/x86 Message-ID: <201212011816.qB1IGE2Y064317@svn.freebsd.org>
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Author: avg Date: Sat Dec 1 18:16:14 2012 New Revision: 243764 URL: http://svnweb.freebsd.org/changeset/base/243764 Log: ioapic_program_intpin: program high bits before low bits Programming the low bits has a side-effect if unmasking the pin if it is not disabled. So if an interrupt was pending then it would be delivered with the correct new vector but to the incorrect old LAPIC. This fix could be made clearer by preserving the mask bit while programming the low bits and then explicitly resetting the mask bit after all the programming is done. Probability to trip over the fixed bug could be increased by bootverbose because printing of the interrupt information in ioapic_assign_cpu lengthened the time window during which an interrupt could arrive while a pin is masked. Reported by: Andreas Longwitz <longwitz@incore.de> Tested by: Andreas Longwitz <longwitz@incore.de> MFC after: 12 days Modified: head/sys/x86/x86/io_apic.c Modified: head/sys/x86/x86/io_apic.c ============================================================================== --- head/sys/x86/x86/io_apic.c Sat Dec 1 18:13:53 2012 (r243763) +++ head/sys/x86/x86/io_apic.c Sat Dec 1 18:16:14 2012 (r243764) @@ -311,12 +311,12 @@ ioapic_program_intpin(struct ioapic_ints } /* Write the values to the APIC. */ - intpin->io_lowreg = low; - ioapic_write(io->io_addr, IOAPIC_REDTBL_LO(intpin->io_intpin), low); value = ioapic_read(io->io_addr, IOAPIC_REDTBL_HI(intpin->io_intpin)); value &= ~IOART_DEST; value |= high; ioapic_write(io->io_addr, IOAPIC_REDTBL_HI(intpin->io_intpin), value); + intpin->io_lowreg = low; + ioapic_write(io->io_addr, IOAPIC_REDTBL_LO(intpin->io_intpin), low); } static int
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