From 9dfbf78e4114fcaf4ef61c49885c3ab5bad40d0b Mon Sep 17 00:00:00 2001 From: Madhavan Srinivasan Date: Thu, 18 Jan 2018 00:33:36 +0530 Subject: [PATCH] powerpc/64s: Default l1d_size to 64K in RFI fallback flush If there is no d-cache-size property in the device tree, l1d_size could be zero. We don't actually expect that to happen, it's only been seen on mambo (simulator) in some configurations. A zero-size l1d_size leads to the loop in the asm wrapping around to 2^64-1, and then walking off the end of the fallback area and eventually causing a page fault which is fatal. Just default to 64K which is correct on some CPUs, and sane enough to not cause a crash on others. Fixes: aa8a5e0062ac9 ('powerpc/64s: Add support for RFI flush of L1-D cache') Signed-off-by: Madhavan Srinivasan [mpe: Rewrite comment and change log] Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/setup_64.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 44c30dd38067..b78f142a4148 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -890,6 +890,17 @@ static void __ref init_fallback_flush(void) return; l1d_size = ppc64_caches.l1d.size; + + /* + * If there is no d-cache-size property in the device tree, l1d_size + * could be zero. That leads to the loop in the asm wrapping around to + * 2^64-1, and then walking off the end of the fallback area and + * eventually causing a page fault which is fatal. Just default to + * something vaguely sane. + */ + if (!l1d_size) + l1d_size = (64 * 1024); + limit = min(ppc64_bolted_size(), ppc64_rma_size); /*