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authorAndreas Herrmann <andreas.herrmann3@amd.com>2009-06-08 15:55:09 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-09 15:28:46 +0200
commit42937e81a82b6bbc51a309c83da140b3a7ca5945 (patch)
treec6562f38f91de06e00bd12280044e31733ff5ee4 /arch/x86/kernel/cpu
parentc9690998ef48ffefeccb91c70a7739eebdea57f9 (diff)
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@amd.com> Cc: <stable@kernel.org> LKML-Reference: <20090608135509.GA12431@alberich.amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/amd.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 7e4a459daa6..0802e151c2c 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -6,6 +6,7 @@
#include <asm/processor.h>
#include <asm/apic.h>
#include <asm/cpu.h>
+#include <asm/pci-direct.h>
#ifdef CONFIG_X86_64
# include <asm/numa_64.h>
@@ -351,6 +352,15 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
(c->x86_model == 8 && c->x86_mask >= 8))
set_cpu_cap(c, X86_FEATURE_K6_MTRR);
#endif
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI)
+ /* check CPU config space for extended APIC ID */
+ if (c->x86 >= 0xf) {
+ unsigned int val;
+ val = read_pci_config(0, 24, 0, 0x68);
+ if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))
+ set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
+ }
+#endif
}
static void __cpuinit init_amd(struct cpuinfo_x86 *c)