apic, x86: Check if EILVT APIC registers are available (AMD only)

This patch implements checks for the availability of LVT entries
(APIC500-530) and reserves it if used. The check becomes
necessary since we want to let the BIOS provide the LVT offsets.
 The offsets should be determined by the subsystems using it
like those for MCE threshold or IBS.  On K8 only offset 0
(APIC500) and MCE interrupts are supported. Beginning with
family 10h at least 4 offsets are available.

Since offsets must be consistent for all cores, we keep track of
the LVT offsets in software and reserve the offset for the same
vector also to be used on other cores. An offset is freed by
setting the entry to APIC_EILVT_MASKED.

If the BIOS is right, there should be no conflicts. Otherwise a
"[Firmware Bug]: ..." error message is generated. However, if
software does not properly determines the offsets, it is not
necessarily a BIOS bug.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1286360874-1471-2-git-send-email-robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/include/asm/apicdef.h b/arch/x86/include/asm/apicdef.h
index 7fe3b3060f08..a859ca461fb0 100644
--- a/arch/x86/include/asm/apicdef.h
+++ b/arch/x86/include/asm/apicdef.h
@@ -131,6 +131,7 @@
 #define APIC_EILVTn(n)  (0x500 + 0x10 * n)
 #define         APIC_EILVT_NR_AMD_K8    1       /* # of extended interrupts */
 #define         APIC_EILVT_NR_AMD_10H   4
+#define         APIC_EILVT_NR_MAX       APIC_EILVT_NR_AMD_10H
 #define         APIC_EILVT_LVTOFF(x)    (((x) >> 4) & 0xF)
 #define         APIC_EILVT_MSG_FIX      0x0
 #define         APIC_EILVT_MSG_SMI      0x2