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Use the APIC to determine the hardware processor id - x86_64

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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>
This commit is contained in:
Fernando Luis Vazquez Cao 2007-05-09 02:33:28 -07:00 committed by Linus Torvalds
parent a36166c6ef
commit dd988528f4
1 changed files with 6 additions and 8 deletions
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14
include/asm-x86_64/smp.h
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@ -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.