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x86: merge 64 and 32 SMP percpu handling

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Now that pda is allocated as part of percpu, percpu doesn't need to be
accessed through pda.  Unify x86_64 SMP percpu access with x86_32 SMP
one.  Other than the segment register, operand size and the base of
percpu symbols, they behave identical now.

This patch replaces now unnecessary pda->data_offset with a dummy
field which is necessary to keep stack_canary at its place.  This
patch also moves per_cpu_offset initialization out of init_gdt() into
setup_per_cpu_areas().  Note that this change also necessitates
explicit per_cpu_offset initializations in voyager_smp.c.

With this change, x86_OP_percpu()'s are as efficient on x86_64 as on
x86_32 and also x86_64 can use assembly PER_CPU macros.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Tejun Heo
2009-01-13 20:41:35 +09:00
committed by Ingo Molnar
parent 1a51e3a0ae
commit 9939ddaff5
8 changed files with 55 additions and 105 deletions
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15
arch/x86/kernel/setup_percpu.c
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@@ -125,14 +125,14 @@ static void __init setup_per_cpu_maps(void)
#endif
}
#ifdef CONFIG_X86_32
/*
* Great future not-so-futuristic plan: make i386 and x86_64 do it
* the same way
*/
#ifdef CONFIG_X86_64
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
[0] = (unsigned long)__per_cpu_load,
};
#else
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(__per_cpu_offset);
#endif
EXPORT_SYMBOL(__per_cpu_offset);
/*
* Great future plan:
@@ -178,6 +178,7 @@ void __init setup_per_cpu_areas(void)
#endif
memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start);
per_cpu_offset(cpu) = ptr - __per_cpu_start;
#ifdef CONFIG_X86_64
cpu_pda(cpu) = (void *)ptr;
@@ -190,7 +191,7 @@ void __init setup_per_cpu_areas(void)
else
memset(cpu_pda(cpu), 0, sizeof(*cpu_pda(cpu)));
#endif
per_cpu_offset(cpu) = ptr - __per_cpu_start;
per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
}