Commit 4c2de74cc869 ("powerpc/64: Interrupts save PPR on stack rather
than thread_struct") changed sizeof(struct pt_regs) % 16 from 0 to 8,
which causes the interrupt frame allocation on kernel entry to put the
kernel stack out of alignment.
Add a pad field to fix alignment, and add a BUILD_BUG_ON to catch this
in future.
Fixes: 4c2de74cc869 ("powerpc/64: Interrupts save PPR on stack rather
than thread_struct")
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
arch/powerpc/include/asm/ptrace.h | 1 +
arch/powerpc/kernel/setup_64.c | 2 ++
2 files changed, 3 insertions(+)
diff --git a/arch/powerpc/include/asm/ptrace.h
b/arch/powerpc/include/asm/ptrace.h
index f73886a1a7f5..1513292bf046 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -54,6 +54,7 @@ struct pt_regs
#ifdef CONFIG_PPC64
unsigned long ppr;
+ unsigned long pad; /* Maintain 16 byte interrupt stack alignment */
#endif
};
#endif
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 2a51e4cc8246..236c1151a3a7 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -636,6 +636,8 @@ static void *__init alloc_stack(unsigned long limit, int
cpu)
{
unsigned long pa;
+ BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16);
+
pa = memblock_alloc_base_nid(THREAD_SIZE, THREAD_SIZE, limit,
early_cpu_to_node(cpu), MEMBLOCK_NONE);
if (!pa) {
--
2.18.0
