From 62111195800d80c66cdc69063ea3145878c99fbf Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 7 Dec 2006 02:14:02 +0100 Subject: [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 Signed-off-by: Andi Kleen Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden Cc: Jan Beulich Cc: Andi Kleen Cc: James Bottomley Cc: Matt Tolentino Signed-off-by: Andrew Morton --- arch/i386/mach-voyager/voyager_smp.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'arch/i386/mach-voyager') diff --git a/arch/i386/mach-voyager/voyager_smp.c b/arch/i386/mach-voyager/voyager_smp.c index f3fea2ad50f..55428e656a3 100644 --- a/arch/i386/mach-voyager/voyager_smp.c +++ b/arch/i386/mach-voyager/voyager_smp.c @@ -28,6 +28,7 @@ #include #include #include +#include /* TLB state -- visible externally, indexed physically */ DEFINE_PER_CPU(struct tlb_state, cpu_tlbstate) ____cacheline_aligned = { &init_mm, 0 }; @@ -422,6 +423,7 @@ find_smp_config(void) VOYAGER_SUS_IN_CONTROL_PORT); current_thread_info()->cpu = boot_cpu_id; + write_pda(cpu_number, boot_cpu_id); } /* @@ -458,7 +460,7 @@ start_secondary(void *unused) /* 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 @@ do_boot_cpu(__u8 cpu) /* 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 @@ void __init smp_setup_processor_id(void) { current_thread_info()->cpu = hard_smp_processor_id(); + write_pda(cpu_number, hard_smp_processor_id()); } -- cgit v1.2.3