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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/include/asm/mpspec_def.h | |
| parent | bc030d6cb9532877c1c5a3f5e7123344fa24a285 (diff) | |
| download | linux-0-day-cb2ded37fd2e1039f96c8c892da024a8f033add5.tar.gz linux-0-day-cb2ded37fd2e1039f96c8c892da024a8f033add5.tar.xz | |
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/include/asm/mpspec_def.h')
| -rw-r--r-- | arch/x86/include/asm/mpspec_def.h | 7 |
1 files changed, 0 insertions, 7 deletions
diff --git a/arch/x86/include/asm/mpspec_def.h b/arch/x86/include/asm/mpspec_def.h index 4a7f96d7c188e..c0a955a9a0878 100644 --- a/arch/x86/include/asm/mpspec_def.h +++ b/arch/x86/include/asm/mpspec_def.h @@ -15,13 +15,6 @@ #ifdef CONFIG_X86_32 # define MAX_MPC_ENTRY 1024 -# define MAX_APICS 256 -#else -# if NR_CPUS <= 255 -# define MAX_APICS 255 -# else -# define MAX_APICS 32768 -# endif #endif /* Intel MP Floating Pointer Structure */ |