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authorNicholas Piggin <npiggin@gmail.com>2018-11-15 12:34:27 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2018-11-15 14:48:43 +1100
commit66f93c5a02d5ba6ef17fef459143961382593212 (patch)
tree28698e7d100f525b169a199a11fa8c25a8bbf92e /arch
parent437ccdc8ce629470babdda1a7086e2f477048cbd (diff)
powerpc/64: Fix kernel stack 16-byte alignment
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. Quadword (16-byte) alignment for the stack is required by both the 64-bit v1 ABI (v1.9 § 3.2.2) and the 64-bit v2 ABI (v1.1 § 2.2.2.1). 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 <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/ptrace.h1
-rw-r--r--arch/powerpc/kernel/setup_64.c2
2 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index f73886a1a7f5..0b8a735b6d85 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) {