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| author | Yinghai Lu <yinghai@kernel.org> | 2011-01-04 16:38:52 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-01-05 14:09:23 +0100 |
| commit | cb2ded37fd2e1039f96c8c892da024a8f033add5 (patch) | |
| tree | 47dd8e3c19760b17130cedfe40b77299d7cd95af /arch/x86/platform/sfi | |
| parent | bc030d6cb9532877c1c5a3f5e7123344fa24a285 (diff) | |
| download | op-kernel-dev-cb2ded37fd2e1039f96c8c892da024a8f033add5.zip op-kernel-dev-cb2ded37fd2e1039f96c8c892da024a8f033add5.tar.gz | |
x86: Fix APIC ID sizing bug on larger systems, clean up MAX_APICS confusion
Found one x2apic pre-enabled system, x2apic_mode suddenly get
corrupted after register some cpus, when compiled
CONFIG_NR_CPUS=255 instead of 512.
It turns out that generic_processor_info() ==> phyid_set(apicid,
phys_cpu_present_map) causes the problem.
phys_cpu_present_map is sized by MAX_APICS bits, and pre-enabled
system some cpus have an apic id > 255.
The variable after phys_cpu_present_map may get corrupted
silently:
ffffffff828e8420 B phys_cpu_present_map
ffffffff828e8440 B apic_verbosity
ffffffff828e8444 B local_apic_timer_c2_ok
ffffffff828e8448 B disable_apic
ffffffff828e844c B x2apic_mode
ffffffff828e8450 B x2apic_disabled
ffffffff828e8454 B num_processors
...
Actually phys_cpu_present_map is referenced via apic id, instead
index. We should use MAX_LOCAL_APIC instead MAX_APICS.
For 64-bit it will be 32768 in all cases. BSS will increase by 4k bytes
on 64-bit:
text data bss dec filename
21696943 4193748 12787712 38678403 vmlinux.before
21696943 4193748 12791808 38682499 vmlinux.after
No change on 32bit.
Finally we can remove MAX_APCIS that was rather confusing.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
LKML-Reference: <4D23BD9C.3070102@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/platform/sfi')
| -rw-r--r-- | arch/x86/platform/sfi/sfi.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/platform/sfi/sfi.c b/arch/x86/platform/sfi/sfi.c index dd4c281..ca54875 100644 --- a/arch/x86/platform/sfi/sfi.c +++ b/arch/x86/platform/sfi/sfi.c @@ -48,9 +48,9 @@ static void __init mp_sfi_register_lapic_address(unsigned long address) /* All CPUs enumerated by SFI must be present and enabled */ static void __cpuinit mp_sfi_register_lapic(u8 id) { - if (MAX_APICS - id <= 0) { + if (MAX_LOCAL_APIC - id <= 0) { pr_warning("Processor #%d invalid (max %d)\n", - id, MAX_APICS); + id, MAX_LOCAL_APIC); return; } |
