Messages in this thread Patch in this message | | | Date | Wed, 03 Sep 2008 16:58:31 -0700 | From | Suresh Siddha <> | Subject | [patch 1/5] x2apic: fix reserved APIC register accesses in print_local_APIC() |
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From: Yinghai Lu <yhlu.kernel@gmail.com> Subject: x2apic: fix reserved APIC register accesses in print_local_APIC()
APIC_ARBPRI is a reserved register for XAPIC and beyond. APIC_RRR is a reserved register except for 82489DX, APIC for Pentium processors. APIC_EOI is a write only register. APIC_DFR is reserved in x2apic mode.
Access to these registers in x2apic will result in #GP fault. Fix these apic register accesses.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Maciej W. Rozycki <macro@linux-mips.org> ---
Index: tip/arch/x86/kernel/io_apic.c =================================================================== --- tip.orig/arch/x86/kernel/io_apic.c 2008-09-03 14:02:56.000000000 -0700 +++ tip/arch/x86/kernel/io_apic.c 2008-09-03 14:51:24.000000000 -0700 @@ -1751,21 +1751,30 @@ printk(KERN_DEBUG "... APIC TASKPRI: %08x (%02x)\n", v, v & APIC_TPRI_MASK); if (APIC_INTEGRATED(ver)) { /* !82489DX */ - v = apic_read(APIC_ARBPRI); - printk(KERN_DEBUG "... APIC ARBPRI: %08x (%02x)\n", v, - v & APIC_ARBPRI_MASK); + if (!APIC_XAPIC(ver)) { + v = apic_read(APIC_ARBPRI); + printk(KERN_DEBUG "... APIC ARBPRI: %08x (%02x)\n", v, + v & APIC_ARBPRI_MASK); + } v = apic_read(APIC_PROCPRI); printk(KERN_DEBUG "... APIC PROCPRI: %08x\n", v); } - v = apic_read(APIC_EOI); - printk(KERN_DEBUG "... APIC EOI: %08x\n", v); - v = apic_read(APIC_RRR); - printk(KERN_DEBUG "... APIC RRR: %08x\n", v); + /* + * Remote read supported only in the 82489DX and local APIC for + * Pentium processors. + */ + if (!APIC_INTEGRATED(ver) || maxlvt == 3) { + v = apic_read(APIC_RRR); + printk(KERN_DEBUG "... APIC RRR: %08x\n", v); + } + v = apic_read(APIC_LDR); printk(KERN_DEBUG "... APIC LDR: %08x\n", v); - v = apic_read(APIC_DFR); - printk(KERN_DEBUG "... APIC DFR: %08x\n", v); + if (!x2apic_enabled()) { + v = apic_read(APIC_DFR); + printk(KERN_DEBUG "... APIC DFR: %08x\n", v); + } v = apic_read(APIC_SPIV); printk(KERN_DEBUG "... APIC SPIV: %08x\n", v); Index: tip/include/asm-x86/apic.h =================================================================== --- tip.orig/include/asm-x86/apic.h 2008-09-03 14:02:56.000000000 -0700 +++ tip/include/asm-x86/apic.h 2008-09-03 14:43:02.000000000 -0700 @@ -98,6 +98,20 @@ extern void enable_x2apic(void); extern void enable_IR_x2apic(void); extern void x2apic_icr_write(u32 low, u32 id); +static inline int x2apic_enabled(void) +{ + int msr, msr2; + + if (!cpu_has_x2apic) + return 0; + + rdmsr(MSR_IA32_APICBASE, msr, msr2); + if (msr & X2APIC_ENABLE) + return 1; + return 0; +} +#else +#define x2apic_enabled() 0 #endif struct apic_ops { --
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