Hi,
there were still a couple of bugs in walkcbfs, but I got them now.
This patch:
- makes 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 works
With this, I managed to boot both fallback and normal with tinybootblock.
Signed-off-by: Patrick Georgi <[email protected]
Index: src/arch/i386/lib/walkcbfs.S
===================================================================
--- src/arch/i386/lib/walkcbfs.S (revision 5141)
+++ src/arch/i386/lib/walkcbfs.S (working copy)
@@ -28,6 +28,8 @@
clobbers %ebx, %ecx, %edi
*/
walkcbfs:
+ cld
+
mov CBFS_HEADER_PTR, %eax
mov CBFS_HEADER_ROMSIZE(%eax), %ecx
bswap %ecx
@@ -47,6 +49,13 @@
2:
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 */
mov %eax, %ecx
@@ -63,7 +72,8 @@
jmp *%esp
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 */
/* ebx = ecx = (current+offset+len+ALIGN-1) & ~(ALIGN-1) */
@@ -73,26 +83,44 @@
mov CBFS_FILE_LEN(%ebx), %edi
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"
--
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