| Date | Thu, 15 Jan 2015 21:22:09 -0000 | From | Thomas Gleixner <> | Subject | [patch 01/23] x86/apic: Avoid open coded x2apic detection |
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enable_IR_x2apic() grew a open coded x2apic detection. Implement a proper helper function which shares the code with the already existing x2apic_enabled().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/include/asm/apic.h | 18 +++++++++--------- arch/x86/kernel/apic/apic.c | 5 +---- 2 files changed, 10 insertions(+), 13 deletions(-)
Index: tip/arch/x86/include/asm/apic.h =================================================================== --- tip.orig/arch/x86/include/asm/apic.h +++ tip/arch/x86/include/asm/apic.h @@ -108,6 +108,14 @@ extern u64 native_apic_icr_read(void); extern int x2apic_mode; +static inline bool apic_is_x2apic_enabled(void) +{ + u64 msr; + + rdmsrl(MSR_IA32_APICBASE, msr); + return msr & X2APIC_ENABLE; +} + #ifdef CONFIG_X86_X2APIC /* * Make previous memory operations globally visible before @@ -175,15 +183,7 @@ extern void check_x2apic(void); extern void enable_x2apic(void); static inline int x2apic_enabled(void) { - u64 msr; - - if (!cpu_has_x2apic) - return 0; - - rdmsrl(MSR_IA32_APICBASE, msr); - if (msr & X2APIC_ENABLE) - return 1; - return 0; + return cpu_has_x2apic && apic_is_x2apic_enabled(); } #define x2apic_supported() (cpu_has_x2apic) Index: tip/arch/x86/kernel/apic/apic.c =================================================================== --- tip.orig/arch/x86/kernel/apic/apic.c +++ tip/arch/x86/kernel/apic/apic.c @@ -1625,10 +1625,7 @@ void __init enable_IR_x2apic(void) int ret, ir_stat; if (!IS_ENABLED(CONFIG_X86_X2APIC)) { - u64 msr; - - rdmsrl(MSR_IA32_APICBASE, msr); - if (msr & X2APIC_ENABLE) + if (apic_is_x2apic_enabled()) panic("BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS.\n"); }
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