diff options
| author | Yinghai Lu <yinghai@kernel.org> | 2011-12-21 17:45:17 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2011-12-23 11:01:01 -0800 |
| commit | fb209bd891645bb87b9618b724f0b4928e0df3de (patch) | |
| tree | 3b59766238dfedbe9f2164048008f4bb2c18a54e /arch/x86/include/asm | |
| parent | a35fd28256e7736cc84af8931a16224f0bfaaf6c (diff) | |
x86, x2apic: Fallback to xapic when BIOS doesn't setup interrupt-remapping
On some of the recent Intel SNB platforms, by default bios is pre-enabling
x2apic mode in the cpu with out setting up interrupt-remapping.
This case was resulting in the kernel to panic as the cpu is already in
x2apic mode but the OS was not able to enable interrupt-remapping (which
is a pre-req for using x2apic capability).
On these platforms all the apic-ids are < 255 and the kernel can fallback to
xapic mode if the bios has not enabled interrupt-remapping (which is
mostly the case if the bios has not exported interrupt-remapping tables to the
OS).
Reported-by: Berck E. Nash <flyboy@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20111222014632.600418637@sbsiddha-desk.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/apic.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/apicdef.h | 1 |
2 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index a0f541a3094..a12d57193fe 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -176,6 +176,7 @@ static inline u64 native_x2apic_icr_read(void) } extern int x2apic_phys; +extern int x2apic_preenabled; extern void check_x2apic(void); extern void enable_x2apic(void); extern void x2apic_icr_write(u32 low, u32 id); @@ -198,6 +199,9 @@ static inline void x2apic_force_phys(void) x2apic_phys = 1; } #else +static inline void disable_x2apic(void) +{ +} static inline void check_x2apic(void) { } diff --git a/arch/x86/include/asm/apicdef.h b/arch/x86/include/asm/apicdef.h index 3925d800786..134bba00df0 100644 --- a/arch/x86/include/asm/apicdef.h +++ b/arch/x86/include/asm/apicdef.h @@ -144,6 +144,7 @@ #define APIC_BASE (fix_to_virt(FIX_APIC_BASE)) #define APIC_BASE_MSR 0x800 +#define XAPIC_ENABLE (1UL << 11) #define X2APIC_ENABLE (1UL << 10) #ifdef CONFIG_X86_32 |