From patchwork Thu Jan 23 14:47:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11348311 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD0CB14B4 for ; Thu, 23 Jan 2020 14:48:32 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B54F32073A for ; Thu, 23 Jan 2020 14:48:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B54F32073A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A70AB6FD3D; Thu, 23 Jan 2020 14:48:31 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 380F26FD3F for ; Thu, 23 Jan 2020 14:48:30 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 19983743-1500050 for multiple; Thu, 23 Jan 2020 14:47:58 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Thu, 23 Jan 2020 14:47:56 +0000 Message-Id: <20200123144756.1403252-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200122201822.889250-1-chris@chris-wilson.co.uk> References: <20200122201822.889250-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v3] drm/i915/gt: Poison GTT scratch pages X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Using a clear page for scratch means that we have relatively benign errors in case it is accidentally used, but that can be rather too benign for debugging. If we poison the scratch, ideally it quickly results in an obvious error. v2: Set each page individually just in case we are using highmem for our scratch page. v3: Pick a new scratch register as MI_STORE_REGISTER_MEM does not work with GPR0 on gen7, unbelievably. Suggested-by: Mika Kuoppala Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Matthew Auld --- .../drm/i915/gem/selftests/i915_gem_context.c | 62 +++++++++++++++++-- drivers/gpu/drm/i915/gt/intel_gtt.c | 30 +++++++++ 2 files changed, 86 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c index 7fc46861a54d..cae3c0004a40 100644 --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c @@ -1575,7 +1575,6 @@ static int read_from_scratch(struct i915_gem_context *ctx, struct drm_i915_private *i915 = ctx->i915; struct drm_i915_gem_object *obj; struct i915_address_space *vm; - const u32 RCS_GPR0 = 0x2600; /* not all engines have their own GPR! */ const u32 result = 0x100; struct i915_request *rq; struct i915_vma *vma; @@ -1596,20 +1595,24 @@ static int read_from_scratch(struct i915_gem_context *ctx, memset(cmd, POISON_INUSE, PAGE_SIZE); if (INTEL_GEN(i915) >= 8) { + const u32 GPR0 = engine->mmio_base + 0x600; + *cmd++ = MI_LOAD_REGISTER_MEM_GEN8; - *cmd++ = RCS_GPR0; + *cmd++ = GPR0; *cmd++ = lower_32_bits(offset); *cmd++ = upper_32_bits(offset); *cmd++ = MI_STORE_REGISTER_MEM_GEN8; - *cmd++ = RCS_GPR0; + *cmd++ = GPR0; *cmd++ = result; *cmd++ = 0; } else { + const u32 reg = engine->mmio_base + 0x420; + *cmd++ = MI_LOAD_REGISTER_MEM; - *cmd++ = RCS_GPR0; + *cmd++ = reg; *cmd++ = offset; *cmd++ = MI_STORE_REGISTER_MEM; - *cmd++ = RCS_GPR0; + *cmd++ = reg; *cmd++ = result; } *cmd = MI_BATCH_BUFFER_END; @@ -1686,6 +1689,39 @@ static int read_from_scratch(struct i915_gem_context *ctx, return err; } +static int check_scratch_page(struct i915_gem_context *ctx, u32 *out) +{ + struct i915_address_space *vm; + struct page *page; + u32 *vaddr; + int err = 0; + + vm = ctx_vm(ctx); + if (!vm) + return -ENODEV; + + page = vm->scratch[0].base.page; + if (!page) { + pr_err("No scratch page!\n"); + return -EINVAL; + } + + vaddr = kmap(page); + if (vaddr) { + pr_err("No (mappable) scratch page!\n"); + return -EINVAL; + } + + memcpy(out, vaddr, sizeof(*out)); + if (memchr_inv(vaddr, *out, PAGE_SIZE)) { + pr_err("Inconsistent initial state of scratch page!\n"); + err = -EINVAL; + } + kunmap(page); + + return err; +} + static int igt_vm_isolation(void *arg) { struct drm_i915_private *i915 = arg; @@ -1696,6 +1732,7 @@ static int igt_vm_isolation(void *arg) I915_RND_STATE(prng); struct file *file; u64 vm_total; + u32 expected; int err; if (INTEL_GEN(i915) < 7) @@ -1730,6 +1767,15 @@ static int igt_vm_isolation(void *arg) if (ctx_vm(ctx_a) == ctx_vm(ctx_b)) goto out_file; + /* Read the initial state of the scratch page */ + err = check_scratch_page(ctx_a, &expected); + if (err) + goto out_file; + + err = check_scratch_page(ctx_b, &expected); + if (err) + goto out_file; + vm_total = ctx_vm(ctx_a)->total; GEM_BUG_ON(ctx_vm(ctx_b)->total != vm_total); vm_total -= I915_GTT_PAGE_SIZE; @@ -1743,6 +1789,10 @@ static int igt_vm_isolation(void *arg) if (!intel_engine_can_store_dword(engine)) continue; + /* Not all engines have their own GPR! */ + if (INTEL_GEN(i915) < 8 && engine->class != RENDER_CLASS) + continue; + while (!__igt_timeout(end_time, NULL)) { u32 value = 0xc5c5c5c5; u64 offset; @@ -1760,7 +1810,7 @@ static int igt_vm_isolation(void *arg) if (err) goto out_file; - if (value) { + if (value != expected) { pr_err("%s: Read %08x from scratch (offset 0x%08x_%08x), after %lu reads!\n", engine->name, value, upper_32_bits(offset), diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c index 45d8e0019a8e..bb9a6e638175 100644 --- a/drivers/gpu/drm/i915/gt/intel_gtt.c +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c @@ -299,6 +299,25 @@ fill_page_dma(const struct i915_page_dma *p, const u64 val, unsigned int count) kunmap_atomic(memset64(kmap_atomic(p->page), val, count)); } +static void poison_scratch_page(struct page *page, unsigned long size) +{ + if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) + return; + + GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE)); + + do { + void *vaddr; + + vaddr = kmap(page); + memset(vaddr, POISON_FREE, PAGE_SIZE); + kunmap(page); + + page = pfn_to_page(page_to_pfn(page) + 1); + size -= PAGE_SIZE; + } while (size); +} + int setup_scratch_page(struct i915_address_space *vm, gfp_t gfp) { unsigned long size; @@ -331,6 +350,17 @@ int setup_scratch_page(struct i915_address_space *vm, gfp_t gfp) if (unlikely(!page)) goto skip; + /* + * Use a non-zero scratch page for debugging. + * + * We want a value that should be reasonably obvious + * to spot in the error state, while also causing a GPU hang + * if executed. We prefer using a clear page in production, so + * should it ever be accidentally used, the effect should be + * fairly benign. + */ + poison_scratch_page(page, size); + addr = dma_map_page_attrs(vm->dma, page, 0, size, PCI_DMA_BIDIRECTIONAL,