@@ -3,6 +3,8 @@
* Copyright © 2019 Intel Corporation
*/
+#include <linux/prandom.h>
+
#include "intel_memory_region.h"
#include "i915_drv.h"
#include "i915_ttm_buddy_manager.h"
@@ -29,6 +31,99 @@ static const struct {
},
};
+static int __iopagetest(struct intel_memory_region *mem,
+ u8 __iomem *va, int pagesize,
+ u8 value, resource_size_t offset,
+ const void *caller)
+{
+ int byte = prandom_u32_max(pagesize);
+ u8 result[3];
+
+ memset_io(va, value, pagesize); /* or GPF! */
+ wmb();
+
+ result[0] = ioread8(va);
+ result[1] = ioread8(va + byte);
+ result[2] = ioread8(va + pagesize - 1);
+ if (memchr_inv(result, value, sizeof(result))) {
+ dev_err(mem->i915->drm.dev,
+ "Failed to read back from memory region:%pR at [%pa + %pa] for %ps; wrote %x, read (%x, %x, %x)\n",
+ &mem->region, &mem->io_start, &offset, caller,
+ value, result[0], result[1], result[2]);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int iopagetest(struct intel_memory_region *mem,
+ resource_size_t offset,
+ const void *caller)
+{
+ const u8 val[] = { 0x0, 0xa5, 0xc3, 0xf0 };
+ void __iomem *va;
+ int err;
+ int i;
+
+ va = ioremap_wc(mem->io_start + offset, PAGE_SIZE);
+ if (!va) {
+ dev_err(mem->i915->drm.dev,
+ "Failed to ioremap memory region [%pa + %px] for %ps\n",
+ &mem->io_start, &offset, caller);
+ return -EFAULT;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(val); i++) {
+ err = __iopagetest(mem, va, PAGE_SIZE, val[i], offset, caller);
+ if (err)
+ break;
+
+ err = __iopagetest(mem, va, PAGE_SIZE, ~val[i], offset, caller);
+ if (err)
+ break;
+ }
+
+ iounmap(va);
+ return err;
+}
+
+static resource_size_t random_page(resource_size_t last)
+{
+ /* Limited to low 44b (16TiB), but should suffice for a spot check */
+ return prandom_u32_max(last >> PAGE_SHIFT) << PAGE_SHIFT;
+}
+
+static int iomemtest(struct intel_memory_region *mem, const void *caller)
+{
+ resource_size_t last = resource_size(&mem->region) - PAGE_SIZE;
+ int err;
+
+ /*
+ * Quick test to check read/write access to the iomap (backing store).
+ *
+ * Write a byte, read it back. If the iomapping fails, we expect
+ * a GPF preventing further execution. If the backing store does not
+ * exist, the read back will return garbage. We check a couple of pages,
+ * the first and last of the specified region to confirm the backing
+ * store + iomap does cover the entire memory region; and we check
+ * a random offset within as a quick spot check for bad memory.
+ */
+
+ err = iopagetest(mem, 0, caller);
+ if (err)
+ return err;
+
+ err = iopagetest(mem, last, caller);
+ if (err)
+ return err;
+
+ err = iopagetest(mem, random_page(last), caller);
+ if (err)
+ return err;
+
+ return 0;
+}
+
struct intel_memory_region *
intel_memory_region_lookup(struct drm_i915_private *i915,
u16 class, u16 instance)
@@ -90,6 +185,21 @@ void intel_memory_region_debug(struct intel_memory_region *mr,
&mr->total, &mr->avail);
}
+static int intel_memory_region_memtest(struct intel_memory_region *mem,
+ void *caller)
+{
+ struct drm_i915_private *i915 = mem->i915;
+ int err = 0;
+
+ if (!mem->io_start)
+ return 0;
+
+ if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+ err = iomemtest(mem, caller);
+
+ return err;
+}
+
struct intel_memory_region *
intel_memory_region_create(struct drm_i915_private *i915,
resource_size_t start,
@@ -126,8 +236,15 @@ intel_memory_region_create(struct drm_i915_private *i915,
goto err_free;
}
+ err = intel_memory_region_memtest(mem, (void *)_RET_IP_);
+ if (err)
+ goto err_release;
+
return mem;
+err_release:
+ if (mem->ops->release)
+ mem->ops->release(mem);
err_free:
kfree(mem);
return ERR_PTR(err);