From: Christophe Leroy <christophe.leroy@xxxxxxxxxx> [ Upstream commit a4719f5bb6d7dc220bffdc1b9f5ce5eaa5543581 ] The check of the emergency context initialisation in vmap_stack_overflow is buggy for the SMP case, as it compares r1 with 0 while in the SMP case r1 is offseted by the CPU id. Instead of fixing it, just perform static initialisation of the first emergency context. Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/4a67ba422be75713286dca0c86ee0d3df2eb6dfa.1615552867.git.christophe.leroy@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/powerpc/kernel/head_32.h | 6 +----- arch/powerpc/kernel/setup_32.c | 2 +- 2 files changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index fef0b34a77c9..f8e3d15ddf69 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -338,11 +338,7 @@ label: lis r1, emergency_ctx@ha #endif lwz r1, emergency_ctx@l(r1) - cmpwi cr1, r1, 0 - bne cr1, 1f - lis r1, init_thread_union@ha - addi r1, r1, init_thread_union@l -1: addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE + addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE EXCEPTION_PROLOG_2 SAVE_NVGPRS(r11) addi r3, r1, STACK_FRAME_OVERHEAD diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c index 057d6b8e9bb0..e7f2eb7837fc 100644 --- a/arch/powerpc/kernel/setup_32.c +++ b/arch/powerpc/kernel/setup_32.c @@ -164,7 +164,7 @@ void __init irqstack_early_init(void) } #ifdef CONFIG_VMAP_STACK -void *emergency_ctx[NR_CPUS] __ro_after_init; +void *emergency_ctx[NR_CPUS] __ro_after_init = {[0] = &init_stack}; void __init emergency_stack_init(void) { -- 2.30.2
