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authorFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>2007-05-09 02:33:28 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-09 12:30:48 -0700
commitdd988528f4a7d64908b427c251d727f3c3e88add (patch)
tree6a11ed178206e7310be3ddc2524a278db6fec5bb
parenta36166c6ef45081fea6eeaf5ca785d7ed786b6e2 (diff)
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>
-rw-r--r--include/asm-x86_64/smp.h14
1 files changed, 6 insertions, 8 deletions
diff --git a/include/asm-x86_64/smp.h b/include/asm-x86_64/smp.h
index f62fda52743..3f303d2365e 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.