libpayload: Fix reading x86 CBFS images from RAM
Three issues:
1. the hardcoded dereferenced pointer at 0xfffffffc
2. "RAM media" has no idea about ROM relative addresses
3. off-by-one in RAM media: it's legal to request 4 bytes from 0xfffffffc
Change-Id: I671ac12d412c71dc8e8e6114f2ea13f58dd99c1d
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/2624
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
diff --git a/payloads/libpayload/libcbfs/cbfs.c b/payloads/libpayload/libcbfs/cbfs.c
index 35e48dd..2fb91bf 100644
--- a/payloads/libpayload/libcbfs/cbfs.c
+++ b/payloads/libpayload/libcbfs/cbfs.c
@@ -65,8 +65,14 @@
#if defined(CONFIG_CBFS_HEADER_ROM_OFFSET) && (CONFIG_CBFS_HEADER_ROM_OFFSET)
# define CBFS_HEADER_ROM_ADDRESS (CONFIG_CBFS_HEADER_ROM_OFFSET)
#else
-// Indirect address: only works on 32bit top-aligned systems.
-# define CBFS_HEADER_ROM_ADDRESS (*(uint32_t*)0xfffffffc)
+/* ugly hack: this assumes that "media" exists
+ in the scope where the macro is used. */
+static uint32_t fetch_x86_header(struct cbfs_media *media)
+{
+ uint32_t *header_ptr = media->map(media, 0xfffffffc, 4);
+ return *header_ptr;
+}
+# define CBFS_HEADER_ROM_ADDRESS fetch_x86_header(media)
#endif
#include "cbfs_core.c"