[PATCH] i386: Initialize the per-CPU data area
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>
diff --git a/arch/i386/mach-voyager/voyager_smp.c b/arch/i386/mach-voyager/voyager_smp.c
index f3fea2a..55428e6 100644
--- a/arch/i386/mach-voyager/voyager_smp.c
+++ b/arch/i386/mach-voyager/voyager_smp.c
@@ -28,6 +28,7 @@
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/arch_hooks.h>
+#include <asm/pda.h>
/* TLB state -- visible externally, indexed physically */
DEFINE_PER_CPU(struct tlb_state, cpu_tlbstate) ____cacheline_aligned = { &init_mm, 0 };
@@ -422,6 +423,7 @@
VOYAGER_SUS_IN_CONTROL_PORT);
current_thread_info()->cpu = boot_cpu_id;
+ write_pda(cpu_number, boot_cpu_id);
}
/*
@@ -458,7 +460,7 @@
/* external functions not defined in the headers */
extern void calibrate_delay(void);
- cpu_init();
+ secondary_cpu_init();
/* OK, we're in the routine */
ack_CPI(VIC_CPU_BOOT_CPI);
@@ -578,6 +580,15 @@
/* init_tasks (in sched.c) is indexed logically */
stack_start.esp = (void *) idle->thread.esp;
+ /* Pre-allocate and initialize the CPU's GDT and PDA so it
+ doesn't have to do any memory allocation during the
+ delicate CPU-bringup phase. */
+ if (!init_gdt(cpu, idle)) {
+ printk(KERN_INFO "Couldn't allocate GDT/PDA for CPU %d\n", cpu);
+ cpucount--;
+ return;
+ }
+
irq_ctx_init(cpu);
/* Note: Don't modify initial ss override */
@@ -1963,4 +1974,5 @@
smp_setup_processor_id(void)
{
current_thread_info()->cpu = hard_smp_processor_id();
+ write_pda(cpu_number, hard_smp_processor_id());
}