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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/kernel/acpi | |
| parent | Merge commit 'v2.6.37-rc8' into x86/apic (diff) | |
| download | linux-dev-cb2ded37fd2e1039f96c8c892da024a8f033add5.tar.xz linux-dev-cb2ded37fd2e1039f96c8c892da024a8f033add5.zip | |
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/kernel/acpi')
| -rw-r--r-- | arch/x86/kernel/acpi/boot.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 7235e5fbdb6d..17c8090fabd4 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -915,13 +915,13 @@ static int __init acpi_parse_madt_lapic_entries(void) acpi_register_lapic_address(acpi_lapic_addr); count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_SAPIC, - acpi_parse_sapic, MAX_APICS); + acpi_parse_sapic, MAX_LOCAL_APIC); if (!count) { x2count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_X2APIC, - acpi_parse_x2apic, MAX_APICS); + acpi_parse_x2apic, MAX_LOCAL_APIC); count = acpi_table_parse_madt(ACPI_MADT_TYPE_LOCAL_APIC, - acpi_parse_lapic, MAX_APICS); + acpi_parse_lapic, MAX_LOCAL_APIC); } if (!count && !x2count) { printk(KERN_ERR PREFIX "No LAPIC entries present\n"); |