tip-bot for Andreas Herrmann wrote: > Commit-ID: 37f36c1017f0032fa7a1fb85a0cddfc0d526d17f > Gitweb: http://git.kernel.org/tip/37f36c1017f0032fa7a1fb85a0cddfc0d526d17f > Author: Andreas Herrmann <andreas.herrmann3@xxxxxxx> > AuthorDate: Thu, 4 Jun 2009 12:40:16 +0200 > Committer: Ingo Molnar <mingo@xxxxxxx> > CommitDate: Sun, 7 Jun 2009 16:39:38 +0200 > > x86: Detect use of extended APIC ID for AMD CPUs > > Booting a 32-bit kernel on Magny-Cours results in the following panic > > ... > Using APIC driver default > ... > Overriding APIC driver with bigsmp > ... > Getting VERSION: 80050010 > Getting VERSION: 80050010 > Getting ID: 10000000 > Getting ID: ef000000 > Getting LVT0: 700 > Getting LVT1: 10000 > Kernel panic - not syncing: Boot APIC ID in local APIC unexpected (16 vs 0) > Pid: 1, comm: swapper Not tainted 2.6.30-rcX #2 > Call Trace: > [<c05194da>] ? panic+0x38/0xd3 > [<c0743102>] ? native_smp_prepare_cpus+0x259/0x31f > [<c073b19d>] ? kernel_init+0x3e/0x141 > [<c073b15f>] ? kernel_init+0x0/0x141 > [<c020325f>] ? kernel_thread_helper+0x7/0x10 > > The reason is that default_get_apic_id handled extension of local APIC > ID field just in case of XAPIC. > > Thus for this AMD CPU, default_get_apic_id() returns 0 and > bigsmp_get_apic_id() returns 16 which leads to the respective kernel > panic. > > This patch introduces a Linux specific feature flag to indicate > support for extended APIC id (8 bits instead of 4 bits width) and sets > the flag on AMD CPUs if applicable. > > Signed-off-by: Andreas Herrmann <andreas.herrmann3@xxxxxxx> > Cc: <stable@xxxxxxxxxx> > LKML-Reference: <20090604104016.GT5736@xxxxxxxxxxxxxxxx> > Signed-off-by: Ingo Molnar <mingo@xxxxxxx> > > > --- > arch/x86/include/asm/apic.h | 2 +- > arch/x86/include/asm/cpufeature.h | 1 + > arch/x86/kernel/cpu/amd.c | 10 ++++++++++ > 3 files changed, 12 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index 42f2f83..9b2c049 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -410,7 +410,7 @@ static inline unsigned default_get_apic_id(unsigned long x) > { > unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR)); > > - if (APIC_XAPIC(ver)) > + if (APIC_XAPIC(ver) || boot_cpu_has(X86_FEATURE_EXTD_APICID)) > return (x >> 24) & 0xFF; > else > return (x >> 24) & 0x0F; looks like we should fix APIC_XAPIC() or have one global apic_ver. YH -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html