Hi,

On 14-10-2019 11:11, Luis Chamberlain wrote:

On Fri, Oct 04, 2019 at 04:50:49PM +0200, Hans de Goede wrote:

quoted

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8d3e778e988b..abba49c4c46d 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c

@@ -314,6 +315,55 @@ static __init int efivar_ssdt_load(void)
  static inline int efivar_ssdt_load(void) { return 0; }
  #endif
  
+#ifdef CONFIG_DEBUG_FS
+
+#define EFI_DEBUGFS_MAX_BLOBS 32
+
+static struct debugfs_blob_wrapper debugfs_blob[EFI_DEBUGFS_MAX_BLOBS];
+
+static void __init efi_debugfs_init(void)
+{
+	struct dentry *efi_debugfs;
+	efi_memory_desc_t *md;
+	char name[32];
+	int type_count[EFI_BOOT_SERVICES_DATA + 1] = {};
+	int i = 0;
+
+	efi_debugfs = debugfs_create_dir("efi", NULL);
+	if (IS_ERR_OR_NULL(efi_debugfs))
+		return;
+
+	for_each_efi_memory_desc(md) {
+		switch (md->type) {
+		case EFI_BOOT_SERVICES_CODE:
+			snprintf(name, sizeof(name), "boot_services_code%d",
+				 type_count[md->type]++);
+			break;
+		case EFI_BOOT_SERVICES_DATA:
+			snprintf(name, sizeof(name), "boot_services_data%d",
+				 type_count[md->type]++);
+			break;
+		default:
+			continue;
+		}
+
+		debugfs_blob[i].size = md->num_pages << EFI_PAGE_SHIFT;
+		debugfs_blob[i].data = memremap(md->phys_addr,
+						debugfs_blob[i].size,
+						MEMREMAP_WB);
+		if (!debugfs_blob[i].data)
+			continue;
+
+		debugfs_create_blob(name, 0400, efi_debugfs, &debugfs_blob[i]);
+		i++;
+		if (i == EFI_DEBUGFS_MAX_BLOBS)
+			break;

Why do we silently ignore more entries ?

A valid remark, I agree that adding a pr_warn_once here would be good
I will do so for the next version.

And could documentation be
added for ways in which this could be used in practice?

I can write a little how to use this to get an embedded firmware,
I will add this to firmware/fallback-mechanisms.rst for the next
version.

Regards,

Hans