fmap: allocate memory as much as discovered fmap size

fmap_find used to read 4096 bytes from the fmap offset blindly. instead, we read
the fmap header first to calcurate the size of the fmap. Then, we read flash
again exactly as much as the discovered fmap.

BUG=none
BRANCH=ToT
TEST=Booted Storm and Peppy. Built all current boards.

Change-Id: Iaa50c1bc3401c77b433af11406d4b9d2e4e722e8
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 755ff66ab0a4d05e6d5410c11a6badb9fcb77a0d
Original-Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Change-Id: Ie5058d181e6565acb70bf108464682dd0e6c1f64
Original-Reviewed-on: https://chromium-review.googlesource.com/231685
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/9556
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 45 insertions, 20 deletions

diff --git a/src/vendorcode/google/chromeos/fmap.c b/src/vendorcode/google/chromeos/fmap.c
index 7c256ce667..50b0248783 100644
--- a/src/vendorcode/google/chromeos/fmap.c
+++ b/src/vendorcode/google/chromeos/fmap.c
@@ -24,6 +24,21 @@
 #include <cbfs.h>
 #include "fmap.h"
 
+static int is_fmap_signature_valid(const struct fmap *fmap)
+{
+	if (memcmp(fmap, FMAP_SIGNATURE, sizeof(FMAP_SIGNATURE) - 1)) {
+		printk(BIOS_ERR, "No FMAP found at %p.\n", fmap);
+		return 1;
+	}
+
+	printk(BIOS_DEBUG, "FMAP: Found \"%s\" version %d.%d at %p.\n",
+	       fmap->name, fmap->ver_major, fmap->ver_minor, fmap);
+	printk(BIOS_DEBUG, "FMAP: base = %llx size = %x #areas = %d\n",
+	       (unsigned long long)fmap->base, fmap->size, fmap->nareas);
+
+	return 0;
+}
+
 /* Find FMAP data structure in ROM.
  * See http://code.google.com/p/flashmap/ for more information on FMAP.
  */
@@ -36,32 +51,42 @@ const struct fmap *fmap_find(void)
 	 * master header; that would require some more changes to cbfstool
 	 * and possibly cros_bundle_firmware.
 	 */
+	const struct fmap *fmap;
+	struct cbfs_media media;
+	size_t size;
 
-#if CONFIG_ARCH_X86
-	/* wrapping around 0x100000000 */
-	const struct fmap *fmap = (void *)
-		(CONFIG_FLASHMAP_OFFSET - CONFIG_ROM_SIZE);
-#else
-	struct cbfs_media default_media, *media;
-	media = &default_media;
-	init_default_cbfs_media(media);
-	media->open(media);
-	const struct fmap *fmap = (void *)
-		media->map(media, CONFIG_FLASHMAP_OFFSET, 4096); // FIXME size
-	media->close(media);
-#endif
+	if (init_default_cbfs_media(&media)) {
+		printk(BIOS_ERR, "failed to init default cbfs media\n");
+		return NULL;
+	}
+
+	media.open(&media);
+	fmap = media.map(&media, CONFIG_FLASHMAP_OFFSET, sizeof(*fmap));
 
-	if (fmap == CBFS_MEDIA_INVALID_MAP_ADDRESS ||
-	    memcmp(fmap, FMAP_SIGNATURE, sizeof(FMAP_SIGNATURE) - 1)) {
-		printk(BIOS_DEBUG, "No FMAP found at %p.\n", fmap);
+	if (fmap == CBFS_MEDIA_INVALID_MAP_ADDRESS) {
+		printk(BIOS_ERR, "failed to map FMAP header\n");
+		media.close(&media);
 		return NULL;
 	}
 
-	printk(BIOS_DEBUG, "FMAP: Found \"%s\" version %d.%d at %p.\n",
-	       fmap->name, fmap->ver_major, fmap->ver_minor, fmap);
-	printk(BIOS_DEBUG, "FMAP: base = %llx size = %x #areas = %d\n",
-	       (unsigned long long)fmap->base, fmap->size, fmap->nareas);
+	if (is_fmap_signature_valid(fmap)) {
+		media.unmap(&media, fmap);
+		media.close(&media);
+		return NULL;
+	}
+
+	size = sizeof(*fmap) + sizeof(struct fmap_area) * fmap->nareas;
+	media.unmap(&media, fmap);
+	fmap = media.map(&media, CONFIG_FLASHMAP_OFFSET, size);
+
+	if (fmap == CBFS_MEDIA_INVALID_MAP_ADDRESS) {
+		printk(BIOS_ERR, "failed to map FMAP (size=%zu)\n", size);
+		media.unmap(&media, fmap);
+		media.close(&media);
+		return NULL;
+	}
 
+	media.close(&media);
 	return fmap;
 }