dynamically allocate emergency stacks

diff -puN arch/ppc64/kernel/pacaData.c~dynamic_emergency_stacks arch/ppc64/kernel/pacaData.c
@@ -27,13 +27,6 @@ struct systemcfg *systemcfg;
  * field correctly */
 extern unsigned long __toc_start;
 
-/* Stack space used when we detect a bad kernel stack pointer, and
- * early in SMP boots before relocation is enabled.
- *
- * ABI requires stack to be 128-byte aligned
- */
-char emergency_stack[PAGE_SIZE * NR_CPUS] __attribute__((aligned(128)));
-
 /* The Paca is an array with one entry per processor.  Each contains an 
  * ItLpPaca, which contains the information shared between the 
  * hypervisor and Linux.  Each also contains an ItLpRegSave area which

@@ -55,7 +48,6 @@ char emergency_stack[PAGE_SIZE * NR_CPUS
 	.kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL,		    \
 	.stab_real = (asrr), 		/* Real pointer to segment table */ \
 	.stab_addr = (asrv),		/* Virt pointer to segment table */ \
-	.emergency_sp = &emergency_stack[((number)+1) * PAGE_SIZE],	    \
 	.cpu_start = (start),		/* Processor start */		    \
 	.lppaca = {							    \
 		.xDesc = 0xd397d781,	/* "LpPa" */			    \

diff -puN arch/ppc64/kernel/setup.c~dynamic_emergency_stacks arch/ppc64/kernel/setup.c
@@ -698,9 +698,12 @@ extern void (*calibrate_delay)(void);
 #ifdef CONFIG_IRQSTACKS
 static void __init irqstack_early_init(void)
 {
-	int i;
+	unsigned int i;
 
-	/* interrupt stacks must be under 256MB, we cannot afford to take SLB misses on them */
+	/* 
+	 * interrupt stacks must be under 256MB, we cannot afford to take
+	 * SLB misses on them.
+	 */
 	for_each_cpu(i) {
 		softirq_ctx[i] = (struct thread_info *)__va(lmb_alloc_base(THREAD_SIZE,
 					THREAD_SIZE, 0x10000000));

@@ -713,6 +716,24 @@ static void __init irqstack_early_init(v
 #endif
 
 /*
+ * Stack space used when we detect a bad kernel stack pointer, and
+ * early in SMP boots before relocation is enabled.
+ */
+static void __init emergency_stack_init(void)
+{
+	unsigned int i;
+
+	/*
+	 * Emergency stacks must be under 256MB, we cannot afford to take 
+	 * SLB misses on them. The ABI also requires them to be 128-byte
+	 * aligned.
+	 */
+	for_each_cpu(i)
+		paca[i].emergency_sp = __va(lmb_alloc_base(PAGE_SIZE, 128,
+						0x10000000)) + PAGE_SIZE;
+}
+
+/*
  * Called into from start_kernel, after lock_kernel has been called.
  * Initializes bootmem, which is unsed to manage page allocation until
  * mem_init is called.

@@ -758,6 +779,7 @@ void __init setup_arch(char **cmdline_p)
 	*cmdline_p = cmd_line;
 
 	irqstack_early_init();
+	emergency_stack_init();
 
 	/* set up the bootmem stuff with available memory */
 	do_init_bootmem();