[POWERPC] Make emergency stack safe for current_thread_info() use

The current_thread_info() macro, used by preempt_count(), assumes the base address and size of the stack are THREAD_SIZE aligned. The emergency stack currently isn't either of these things, which could potentially cause problems anytime we're running on the emergency stack. That includes when we detect a bad kernel stack pointer, and also during early_setup_secondary(). Signed-off-by: Michael Ellerman <[email protected]> Signed-off-by: Paul Mackerras <[email protected]>
mrcsosa · Apr 30, 2008 · 3243d87 · 3243d87
1 parent 595f403
commit 3243d87
Showing 1 changed file with 6 additions and 3 deletions.
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
@@ -487,9 +487,12 @@ static void __init emergency_stack_init(void)
 	 */
 	limit = min(0x10000000UL, lmb.rmo_size);
 
-	for_each_possible_cpu(i)
-		paca[i].emergency_sp =
-		__va(lmb_alloc_base(HW_PAGE_SIZE, 128, limit)) + HW_PAGE_SIZE;
+	for_each_possible_cpu(i) {
+		unsigned long sp;
+		sp  = lmb_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
+		sp += THREAD_SIZE;
+		paca[i].emergency_sp = __va(sp);
+	}
 }
 
 /*