diff options
| author | Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> | 2007-05-09 02:33:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 12:30:48 -0700 |
| commit | dd988528f4a7d64908b427c251d727f3c3e88add (patch) | |
| tree | 6a11ed178206e7310be3ddc2524a278db6fec5bb /include/asm-x86_64 | |
| parent | a36166c6ef45081fea6eeaf5ca785d7ed786b6e2 (diff) | |
| download | lwn-dd988528f4a7d64908b427c251d727f3c3e88add.tar.gz lwn-dd988528f4a7d64908b427c251d727f3c3e88add.zip | |
Use the APIC to determine the hardware processor id - x86_64
hard_smp_processor_id used to be just a macro that hard-coded
hard_smp_processor_id to 0 in the non SMP case. When booting non SMP kernels
on hardware where the boot ioapic id is not 0 this turns out to be a problem.
This is happens frequently in the case of kdump and once in a great while in
the case of real hardware.
Use the APIC to determine the hardware processor id in both UP and SMP kernels
to fix this issue.
Notice that hard_smp_processor_id is only used by SMP code or by code that
works with apics so we do not need to handle the case when apics are not
present and hard_smp_processor_id should never be called there.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-x86_64')
| -rw-r--r-- | include/asm-x86_64/smp.h | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/include/asm-x86_64/smp.h b/include/asm-x86_64/smp.h index f62fda527439..3f303d2365ed 100644 --- a/include/asm-x86_64/smp.h +++ b/include/asm-x86_64/smp.h @@ -57,12 +57,6 @@ static inline int num_booting_cpus(void) #define raw_smp_processor_id() read_pda(cpunumber) -static inline int hard_smp_processor_id(void) -{ - /* we don't want to mark this access volatile - bad code generation */ - return GET_APIC_ID(*(unsigned int *)(APIC_BASE+APIC_ID)); -} - extern int __cpu_disable(void); extern void __cpu_die(unsigned int cpu); extern void prefill_possible_map(void); @@ -71,10 +65,14 @@ extern unsigned __cpuinitdata disabled_cpus; #define NO_PROC_ID 0xFF /* No processor magic marker */ -#else /* CONFIG_SMP */ -#define hard_smp_processor_id() 0 #endif /* CONFIG_SMP */ +static inline int hard_smp_processor_id(void) +{ + /* we don't want to mark this access volatile - bad code generation */ + return GET_APIC_ID(*(unsigned int *)(APIC_BASE+APIC_ID)); +} + /* * Some lowlevel functions might want to know about * the real APIC ID <-> CPU # mapping. |