x86-64: Convert irqstacks to per-cpu

Move the irqstackptr variable from the PDA to per-cpu.  Make the
stacks themselves per-cpu, removing some specific allocation code.
Add a seperate flag (is_boot_cpu) to simplify the per-cpu boot
adjustments.

tj: * sprinkle some underbars around.

    * irq_stack_ptr is not used till traps_init(), no reason to
      initialize it early.  On SMP, just leaving it NULL till proper
      initialization in setup_per_cpu_areas() works.  Dropped
      is_boot_cpu and early irq_stack_ptr initialization.

    * do DECLARE/DEFINE_PER_CPU(char[IRQ_STACK_SIZE], irq_stack)
      instead of (char, irq_stack[IRQ_STACK_SIZE]).

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 17 insertions, 16 deletions

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index c302d0707048..28e26a4315df 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -106,7 +106,8 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
                 const struct stacktrace_ops *ops, void *data)
 {
         const unsigned cpu = get_cpu();
-        unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
+        unsigned long *irq_stack_end =
+                (unsigned long *)per_cpu(irq_stack_ptr, cpu);
         unsigned used = 0;
         struct thread_info *tinfo;
         int graph = 0;
@@ -160,23 +161,23 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
                         stack = (unsigned long *) estack_end[-2];
                         continue;
                 }
-                if (irqstack_end) {
-                        unsigned long *irqstack;
-                        irqstack = irqstack_end -
-                                (IRQSTACKSIZE - 64) / sizeof(*irqstack);
+                if (irq_stack_end) {
+                        unsigned long *irq_stack;
+                        irq_stack = irq_stack_end -
+                                (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
 
-                        if (stack >= irqstack && stack < irqstack_end) {
+                        if (stack >= irq_stack && stack < irq_stack_end) {
                                 if (ops->stack(data, "IRQ") < 0)
                                         break;
                                 bp = print_context_stack(tinfo, stack, bp,
-                                        ops, data, irqstack_end, &graph);
+                                        ops, data, irq_stack_end, &graph);
                                 /*
                                  * We link to the next stack (which would be
                                  * the process stack normally) the last
                                  * pointer (index -1 to end) in the IRQ stack:
                                  */
-                                stack = (unsigned long *) (irqstack_end[-1]);
-                                irqstack_end = NULL;
+                                stack = (unsigned long *) (irq_stack_end[-1]);
+                                irq_stack_end = NULL;
                                 ops->stack(data, "EOI");
                                 continue;
                         }
@@ -199,10 +200,10 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
         unsigned long *stack;
         int i;
         const int cpu = smp_processor_id();
-        unsigned long *irqstack_end =
-                (unsigned long *) (cpu_pda(cpu)->irqstackptr);
-        unsigned long *irqstack =
-                (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE);
+        unsigned long *irq_stack_end =
+                (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
+        unsigned long *irq_stack =
+                (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
 
         /*
          * debugging aid: "show_stack(NULL, NULL);" prints the
@@ -218,9 +219,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 
         stack = sp;
         for (i = 0; i < kstack_depth_to_print; i++) {
-                if (stack >= irqstack && stack <= irqstack_end) {
-                        if (stack == irqstack_end) {
-                                stack = (unsigned long *) (irqstack_end[-1]);
+                if (stack >= irq_stack && stack <= irq_stack_end) {
+                        if (stack == irq_stack_end) {
+                                stack = (unsigned long *) (irq_stack_end[-1]);
                                 printk(" <EOI> ");
                         }
                 } else {