commit: e503f9e4b092e2349a9477a333543de8f3c7f5d9 From: Youquan Song <[email protected]> Date: Fri, 22 Apr 2011 00:22:43 +0800 Subject: [PATCH] x86, apic: Fix spurious error interrupts triggering on all non-boot APs
This patch fixes a bug reported by a customer, who found that many unreasonable error interrupts reported on all non-boot CPUs (APs) during the system boot stage. According to Chapter 10 of Intel Software Developer Manual Volume 3A, Local APIC may signal an illegal vector error when an LVT entry is set as an illegal vector value (0~15) under FIXED delivery mode (bits 8-11 is 0), regardless of whether the mask bit is set or an interrupt actually happen. These errors are seen as error interrupts. The initial value of thermal LVT entries on all APs always reads 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI sequence to them and LVT registers are reset to 0s except for the mask bits which are set to 1s when APs receive INIT IPI. When the BIOS takes over the thermal throttling interrupt, the LVT thermal deliver mode should be SMI and it is required from the kernel to keep AP's LVT thermal monitoring register programmed as such as well. This issue happens when BIOS does not take over thermal throttling interrupt, AP's LVT thermal monitor register will be restored to 0x10000 which means vector 0 and fixed deliver mode, so all APs will signal illegal vector error interrupts. This patch check if interrupt delivery mode is not fixed mode before restoring AP's LVT thermal monitor register. Signed-off-by: Youquan Song <[email protected]> Acked-by: Suresh Siddha <[email protected]> Acked-by: Yong Wang <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: <[email protected]> # As far back as possible Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/apicdef.h | 1 + arch/x86/kernel/cpu/mcheck/therm_throt.c | 12 +++++++----- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/apicdef.h b/arch/x86/include/asm/apicdef.h index d87988b..34595d5 100644 --- a/arch/x86/include/asm/apicdef.h +++ b/arch/x86/include/asm/apicdef.h @@ -78,6 +78,7 @@ #define APIC_DEST_LOGICAL 0x00800 #define APIC_DEST_PHYSICAL 0x00000 #define APIC_DM_FIXED 0x00000 +#define APIC_DM_FIXED_MASK 0x00700 #define APIC_DM_LOWEST 0x00100 #define APIC_DM_SMI 0x00200 #define APIC_DM_REMRD 0x00300 diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c index 6f8c5e9..0f03446 100644 --- a/arch/x86/kernel/cpu/mcheck/therm_throt.c +++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c @@ -446,18 +446,20 @@ void intel_init_thermal(struct cpuinfo_x86 *c) */ rdmsr(MSR_IA32_MISC_ENABLE, l, h); + h = lvtthmr_init; /* * The initial value of thermal LVT entries on all APs always reads * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI * sequence to them and LVT registers are reset to 0s except for * the mask bits which are set to 1s when APs receive INIT IPI. - * Always restore the value that BIOS has programmed on AP based on - * BSP's info we saved since BIOS is always setting the same value - * for all threads/cores + * If BIOS takes over the thermal interrupt and sets its interrupt + * delivery mode to SMI (not fixed), it restores the value that the + * BIOS has programmed on AP based on BSP's info we saved since BIOS + * is always setting the same value for all threads/cores. */ - apic_write(APIC_LVTTHMR, lvtthmr_init); + if ((h & APIC_DM_FIXED_MASK) != APIC_DM_FIXED) + apic_write(APIC_LVTTHMR, lvtthmr_init); - h = lvtthmr_init; if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) { printk(KERN_DEBUG _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
