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[PATCH] i386: Initialize the per-CPU data area

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When a CPU is brought up, a PDA and GDT are allocated for it.  The GDT's
__KERNEL_PDA entry is pointed to the allocated PDA memory, so that all
references using this segment descriptor will refer to the PDA.

This patch rearranges CPU initialization a bit, so that the GDT/PDA are set up
as early as possible in cpu_init().  Also for secondary CPUs, GDT+PDA are
preallocated and initialized so all the secondary CPU needs to do is set up
the ldt and load %gs.  This will be important once smp_processor_id() and
current use the PDA.

In all cases, the PDA is set up in head.S, before a CPU starts running C code,
so the PDA is always available.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
This commit is contained in:
Jeremy Fitzhardinge 2006-12-07 02:14:02 +01:00 • committed by Andi Kleen
commit 6211119580
4 changed files with 177 additions and 55 deletions
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3
include/asm-i386/processor.h
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@ -727,4 +727,7 @@ extern unsigned long boot_option_idle_override;
extern void enable_sep_cpu(void);
extern int sysenter_setup(void);
extern int init_gdt(int cpu, struct task_struct *idle);
extern void secondary_cpu_init(void);
#endif /* __ASM_I386_PROCESSOR_H */