Changeset 5144

Timestamp:

Feb 22, 2010 1:58:01 PM (3 years ago)

Author:

oxygene

Message:

• Make walkcbfs capable of loading files other than the first
• Look more closely for files, which should make the code robust against defective CBFS images, as long as the bootblock is usable.

Signed-off-by: Patrick Georgi <patrick.georgi@…>
Acked-by: Peter Stuge <peter@…>

File:

• trunk/src/arch/i386/lib/walkcbfs.S (modified) (4 diffs)

trunk/src/arch/i386/lib/walkcbfs.S

@@ -29 +29 @@
 */
 walkcbfs:
+        cld
+
         mov CBFS_HEADER_PTR, %eax
         mov CBFS_HEADER_ROMSIZE(%eax), %ecx
@@ -48 +50 @@
         add $1, %eax
 walker:
+        mov 0(%ebx), %edi
+        cmp %edi, filemagic
+        jne searchfile
+        mov 4(%ebx), %edi
+        cmp %edi, filemagic+4
+        jne searchfile
+
         mov %ebx, %edi
         add $CBFS_FILE_STRUCTSIZE, %edi /* edi = address of first byte after struct cbfs_file */
@@ -64 +73 @@
 
 tryharder:
-        sub %ebx, %edi /* edi = # of walked bytes */
+        sub %ebx, %edi
+        sub $CBFS_FILE_STRUCTSIZE, %edi /* edi = # of walked bytes */
         sub %edi, %esi /* esi = start of filename */
 
@@ -74 +84 @@
         bswap %edi
         add %edi, %ecx
-        mov CBFS_HEADER_PTR, %ebx
-        mov CBFS_HEADER_ALIGN(%ebx), %ebx
-        bswap %ebx
-        sub $1, %ebx
-        add %ebx, %ecx
-        mov %ebx, %edi
+        mov CBFS_HEADER_PTR, %edi
+        mov CBFS_HEADER_ALIGN(%edi), %edi
+        bswap %edi
+        sub $1, %edi
+        add %edi, %ecx
         not %edi
         and %edi, %ecx
+
+        /* if oldaddr >= addr, leave */
+        cmp %ebx, %ecx
+        jbe out
+
         mov %ecx, %ebx
 
-        /* look if we should exit */
+check_for_exit:
+        /* look if we should exit: did we pass into the bootblock already? */
         mov CBFS_HEADER_PTR, %ecx
-        mov CBFS_HEADER_ROMSIZE(%ecx), %ecx
+        mov CBFS_HEADER_BOOTBLOCKSIZE(%ecx), %ecx
         bswap %ecx
         not %ecx
         add $1, %ecx
 
-        cmp %ebx, %ecx
-        /* if we're still inside the ROM area, jump back */
+        cmp %ecx, %ebx
+        /* if bootblockstart >= addr (==we're still in the data area) , jump back */
         jbe walker
 
+out:
         mov $0, %eax
         jmp *%esp
+
+
+searchfile:
+        /* if filemagic isn't found, move forward cbfs_header->align bytes */
+        mov CBFS_HEADER_PTR, %edi
+        mov CBFS_HEADER_ALIGN(%edi), %edi
+        bswap %edi
+        add %edi, %ebx
+        jmp check_for_exit
+
+filemagic:
+        .ascii "LARCHIVE"