Commit 3243d874 authored Apr 30, 2008 by Michael Ellerman Committed by Paul Mackerras Apr 30, 2008

[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 <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

parent 595f403c

arch/powerpc/kernel/setup_64.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}

		/*