Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757187AbZFDKlW (ORCPT ); Thu, 4 Jun 2009 06:41:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751973AbZFDKlO (ORCPT ); Thu, 4 Jun 2009 06:41:14 -0400 Received: from outbound-dub.frontbridge.com ([213.199.154.16]:41185 "EHLO IE1EHSOBE003.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751169AbZFDKlN (ORCPT ); Thu, 4 Jun 2009 06:41:13 -0400 X-SpamScore: -3 X-BigFish: VPS-3(zz4015Lzz1202hzzz32i6bh17ch61h) X-Spam-TCS-SCL: 0:0 X-WSS-ID: 0KKPN0E-01-PHL-01 Date: Thu, 4 Jun 2009 12:40:16 +0200 From: Andreas Herrmann To: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" CC: linux-kernel@vger.kernel.org Subject: [PATCH] x86: detect use of extended APIC ID for AMD CPUs Message-ID: <20090604104016.GT5736@alberich.amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-09) X-OriginalArrivalTime: 04 Jun 2009 10:41:03.0542 (UTC) FILETIME=[F5537D60:01C9E500] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3703 Lines: 108 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: [] ? panic+0x38/0xd3 [] ? native_smp_prepare_cpus+0x259/0x31f [] ? kernel_init+0x3e/0x141 [] ? kernel_init+0x0/0x141 [] ? 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 --- arch/x86/include/asm/apic.h | 2 +- arch/x86/include/asm/cpufeature.h | 1 + arch/x86/kernel/cpu/amd.c | 9 +++++++++ 3 files changed, 11 insertions(+), 1 deletions(-) Normally you would run 64-bit kernel on such a CPU which correctly handles 8-bit APIC id. So this is not a big issue, but it's still a bug in the 32-bit case. Patch is against tip/master plus 5 patches from "[PATCH 0/5 v3] x86: adapt CPU topology detection for AMD Magny-Cours" Please apply. Thanks, Andreas diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 229d0be..bb7d479 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -402,7 +402,7 @@ 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; diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 7abe596..6143bfb 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -95,6 +95,7 @@ #define X86_FEATURE_NONSTOP_TSC (3*32+24) /* TSC does not stop in C states */ #define X86_FEATURE_CLFLUSH_MONITOR (3*32+25) /* "" clflush reqd with monitor */ #define X86_FEATURE_AMD_DCM (3*32+26) /* multi-node processor */ +#define X86_FEATURE_EXTD_APICID (3*32+27) /* has extended APICID (8 bits) */ /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ #define X86_FEATURE_XMM3 (4*32+ 0) /* "pni" SSE-3 */ diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 8c27925..551adb8 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -409,6 +409,15 @@ 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 +#ifdef CONFIG_X86_LOCAL_APIC + /* 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) -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/