x86: Detect use of extended APIC ID for AMD CPUs (42937e81) · Commits · 戴 / test

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>

arch/x86/include/asm/apic.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

arch/x86/include/asm/cpufeature.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -94,6 +94,7 @@
		#define X86_FEATURE_TSC_RELIABLE (332+23) / TSC is known to be reliable */
		#define X86_FEATURE_NONSTOP_TSC (332+24) / TSC does not stop in C states */
		#define X86_FEATURE_CLFLUSH_MONITOR (332+25) / "" clflush reqd with monitor */
		#define X86_FEATURE_EXTD_APICID (332+26) / has extended APICID (8 bits) */

		/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
		#define X86_FEATURE_XMM3 (432+ 0) / "pni" SSE-3 */

arch/x86/kernel/cpu/amd.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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)

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