x86-64: Convert exception stacks to per-cpu

Move the exception stacks to per-cpu, removing specific allocation code.

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

1 files changed, 8 insertions, 15 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 496f0a01919b..b6d7eec0be77 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -913,8 +913,9 @@ void __cpuinit pda_init(int cpu)
         }
 }
 
-static char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ +
-                                  DEBUG_STKSZ] __page_aligned_bss;
+static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
+        [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ])
+        __aligned(PAGE_SIZE);
 
 extern asmlinkage void ignore_sysret(void);
 
@@ -972,15 +973,12 @@ void __cpuinit cpu_init(void)
         struct tss_struct *t = &per_cpu(init_tss, cpu);
         struct orig_ist *orig_ist = &per_cpu(orig_ist, cpu);
         unsigned long v;
-        char *estacks = NULL;
         struct task_struct *me;
         int i;
 
         /* CPU 0 is initialised in head64.c */
         if (cpu != 0)
                 pda_init(cpu);
-        else
-                estacks = boot_exception_stacks;
 
         me = current;
 
@@ -1014,18 +1012,13 @@ void __cpuinit cpu_init(void)
          * set up and load the per-CPU TSS
          */
         if (!orig_ist->ist[0]) {
-                static const unsigned int order[N_EXCEPTION_STACKS] = {
-                  [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STACK_ORDER,
-                  [DEBUG_STACK - 1] = DEBUG_STACK_ORDER
+                static const unsigned int sizes[N_EXCEPTION_STACKS] = {
+                  [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
+                  [DEBUG_STACK - 1] = DEBUG_STKSZ
                 };
+                char *estacks = per_cpu(exception_stacks, cpu);
                 for (v = 0; v < N_EXCEPTION_STACKS; v++) {
-                        if (cpu) {
-                                estacks = (char *)__get_free_pages(GFP_ATOMIC, order[v]);
-                                if (!estacks)
-                                        panic("Cannot allocate exception "
-                                              "stack %ld %d\n", v, cpu);
-                        }
-                        estacks += PAGE_SIZE << order[v];
+                        estacks += sizes[v];
                         orig_ist->ist[v] = t->x86_tss.ist[v] =
                                         (unsigned long)estacks;
                 }