From e850b89f50d2c1439f58d547b888ee6e43312dea Mon Sep 17 00:00:00 2001 From: Oded Gabbay Date: Sun, 31 Mar 2019 21:37:42 +0300 Subject: [PATCH] habanalabs: prevent CPU soft lockup on Palladium Unmapping ptes in the device MMU on Palladium can take a long time, which can cause a kernel BUG of CPU soft lockup. This patch minimize the chances for this bug by sleeping a little between unmapping ptes. Signed-off-by: Oded Gabbay --- drivers/misc/habanalabs/memory.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/misc/habanalabs/memory.c b/drivers/misc/habanalabs/memory.c index 39788b1..e9e1635 100644 --- a/drivers/misc/habanalabs/memory.c +++ b/drivers/misc/habanalabs/memory.c @@ -1046,10 +1046,17 @@ static int unmap_device_va(struct hl_ctx *ctx, u64 vaddr) mutex_lock(&ctx->mmu_lock); - for (i = 0 ; i < phys_pg_pack->npages ; i++, next_vaddr += page_size) + for (i = 0 ; i < phys_pg_pack->npages ; i++, next_vaddr += page_size) { if (hl_mmu_unmap(ctx, next_vaddr, page_size)) dev_warn_ratelimited(hdev->dev, - "unmap failed for vaddr: 0x%llx\n", next_vaddr); + "unmap failed for vaddr: 0x%llx\n", next_vaddr); + + /* unmapping on Palladium can be really long, so avoid a CPU + * soft lockup bug by sleeping a little between unmapping pages + */ + if (hdev->pldm) + usleep_range(500, 1000); + } hdev->asic_funcs->mmu_invalidate_cache(hdev, true); -- 2.7.4