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authorTejun Heo <tj@kernel.org>2009-01-13 06:41:35 -0500
committerIngo Molnar <mingo@elte.hu>2009-01-16 08:19:46 -0500
commit1a51e3a0aed18767cf2762e95456ecfeb0bca5e6 (patch)
tree2d930218ef1072a59f7dac0f97bb03aa02796c8c /arch/x86/xen
parentc8f3329a0ddd751241e96b4100df7eda14b2cbc6 (diff)
x86: fold pda into percpu area on SMP
[ Based on original patch from Christoph Lameter and Mike Travis. ] Currently pdas and percpu areas are allocated separately. %gs points to local pda and percpu area can be reached using pda->data_offset. This patch folds pda into percpu area. Due to strange gcc requirement, pda needs to be at the beginning of the percpu area so that pda->stack_canary is at %gs:40. To achieve this, a new percpu output section macro - PERCPU_VADDR_PREALLOC() - is added and used to reserve pda sized chunk at the start of the percpu area. After this change, for boot cpu, %gs first points to pda in the data.init area and later during setup_per_cpu_areas() gets updated to point to the actual pda. This means that setup_per_cpu_areas() need to reload %gs for CPU0 while clearing pda area for other cpus as cpu0 already has modified it when control reaches setup_per_cpu_areas(). This patch also removes now unnecessary get_local_pda() and its call sites. A lot of this patch is taken from Mike Travis' "x86_64: Fold pda into per cpu area" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/smp.c10
1 files changed, 0 insertions, 10 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index c44e2069c7c7..83fa4236477d 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -283,16 +283,6 @@ static int __cpuinit xen_cpu_up(unsigned int cpu)
283 struct task_struct *idle = idle_task(cpu); 283 struct task_struct *idle = idle_task(cpu);
284 int rc; 284 int rc;
285 285
286#ifdef CONFIG_X86_64
287 /* Allocate node local memory for AP pdas */
288 WARN_ON(cpu == 0);
289 if (cpu > 0) {
290 rc = get_local_pda(cpu);
291 if (rc)
292 return rc;
293 }
294#endif
295
296#ifdef CONFIG_X86_32 286#ifdef CONFIG_X86_32
297 init_gdt(cpu); 287 init_gdt(cpu);
298 per_cpu(current_task, cpu) = idle; 288 per_cpu(current_task, cpu) = idle;