diff options
Diffstat (limited to 'drivers/gpu/drm/i915/gt/intel_gtt.c')
| -rw-r--r-- | drivers/gpu/drm/i915/gt/intel_gtt.c | 30 |
1 files changed, 30 insertions, 0 deletions
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, |