[PATCH SLOF v4 4/4] disk-label: add support for booting from GPT FAT partition
Nikunj A Dadhania
nikunj at linux.vnet.ibm.com
Thu Jul 2 21:35:38 AEST 2015
For a GPT+LVM combination disk, older bootloader that does not support
LVM, cannot load kernel from LVM.
The patch adds support to read from BASIC_DATA UUID partitions for the
case that the OS installer has installed the CHRP-BOOT config on a FAT
file system.
Makes GPT detection robust
* Fix bug in seek-pos updation code
* Check for Protective MBR Magic
* Check for valid GPT Signature
* Boundary check for allocated block size before reading into the
buffer
Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth at redhat.com>
---
slof/fs/packages/disk-label.fs | 108 ++++++++++++++++++++++++++++++++---------
1 file changed, 84 insertions(+), 24 deletions(-)
diff --git a/slof/fs/packages/disk-label.fs b/slof/fs/packages/disk-label.fs
index 142e54f..e034d64 100644
--- a/slof/fs/packages/disk-label.fs
+++ b/slof/fs/packages/disk-label.fs
@@ -20,6 +20,7 @@ false VALUE debug-disk-label?
\ If we ever want to put a large kernel with initramfs from a PREP partition
\ we might need to increase this value. The default value is 65536 blocks (32MB)
d# 65536 value max-prep-partition-blocks
+d# 4096 CONSTANT block-array-size
s" disk-label" device-name
@@ -152,8 +153,8 @@ CONSTANT /gpt-part-entry
: init-block ( -- )
s" block-size" ['] $call-parent CATCH IF ABORT" parent has no block-size." THEN
to block-size
- d# 4096 alloc-mem
- dup d# 4096 erase
+ block-array-size alloc-mem
+ dup block-array-size erase
to block
debug-disk-label? IF
." init-block: block-size=" block-size .d ." block=0x" block u. cr
@@ -178,7 +179,8 @@ CONSTANT /gpt-part-entry
\ This word returns true if the currently loaded block has _NO_ GPT partition id
: no-gpt? ( -- true|false )
0 read-sector
- 1 partition>part-entry part-entry>id c@ ee <>
+ 1 partition>part-entry part-entry>id c@ ee <> IF true EXIT THEN
+ block mbr>magic w at -le aa55 <>
;
: pc-extended-partition? ( part-entry-addr -- true|false )
@@ -266,7 +268,10 @@ CONSTANT /gpt-part-entry
: try-dos-partition ( -- okay? )
\ Read partition table and check magic.
- no-mbr? IF cr ." No DOS disk-label found." cr false EXIT THEN
+ no-mbr? IF
+ debug-disk-label? IF cr ." No DOS disk-label found." cr THEN
+ false EXIT
+ THEN
count-dos-logical-partitions TO dos-logical-partitions
@@ -376,31 +381,85 @@ AA268B49521E5A8B CONSTANT GPT-PREP-PARTITION-4
8 + x@ GPT-PREP-PARTITION-4 =
;
-: load-from-gpt-prep-partition ( addr -- size )
- no-gpt? IF drop false EXIT THEN
- debug-disk-label? IF
- cr ." GPT partition found " cr
- THEN
- 1 read-sector block gpt>part-entry-lba l at -le
+\ Check for GPT MSFT BASIC DATA GUID - fat based
+EBD0A0A2 CONSTANT GPT-BASIC-DATA-PARTITION-1
+B9E5 CONSTANT GPT-BASIC-DATA-PARTITION-2
+4433 CONSTANT GPT-BASIC-DATA-PARTITION-3
+87C068B6B72699C7 CONSTANT GPT-BASIC-DATA-PARTITION-4
+
+: gpt-basic-data-partition? ( -- true|false )
+ block gpt-part-entry>part-type-guid
+ dup l at -le GPT-BASIC-DATA-PARTITION-1 <> IF drop false EXIT THEN
+ dup 4 + w at -le GPT-BASIC-DATA-PARTITION-2 <> IF drop false EXIT THEN
+ dup 6 + w at -le GPT-BASIC-DATA-PARTITION-3 <> IF drop false EXIT THEN
+ 8 + x@ GPT-BASIC-DATA-PARTITION-4 =
+;
+
+\
+\ GPT Signature
+\ ("EFI PART", 45h 46h 49h 20h 50h 41h 52h 54h)
+\
+4546492050415254 CONSTANT GPT-SIGNATURE
+
+\ The routine checks whether the protective MBR has GPT ID and then
+\ reads the gpt data from the sector. Also set the seek position and
+\ the partition size used in caller routines.
+
+: get-gpt-partition ( -- true|false )
+ no-gpt? IF false EXIT THEN
+ debug-disk-label? IF cr ." GPT partition found " cr THEN
+ 1 read-sector
+ block gpt>part-entry-lba x at -le
block-size * to seek-pos
block gpt>part-entry-size l at -le to gpt-part-size
- block gpt>num-part-entry l at -le dup 0= IF false EXIT THEN
+ gpt-part-size block-array-size > IF
+ cr ." GPT part size exceeds buffer allocated " cr
+ false exit
+ THEN
+ block gpt>signature x@ GPT-SIGNATURE =
+;
+
+: load-from-gpt-prep-partition ( addr -- size )
+ get-gpt-partition 0= IF false EXIT THEN
+ block gpt>num-part-entry l at -le dup 0= IF false exit THEN
1+ 1 ?DO
seek-pos 0 seek drop
block gpt-part-size read drop gpt-prep-partition? IF
- debug-disk-label? IF
- ." GPT PReP partition found " cr
- THEN
- block gpt-part-entry>first-lba x at -le
- block gpt-part-entry>last-lba x at -le
- over - 1+ ( addr offset len )
- swap ( addr len offset )
- block-size * to part-offset
- 0 0 seek drop ( addr len )
- block-size * read ( size )
+ debug-disk-label? IF ." GPT PReP partition found " cr THEN
+ block gpt-part-entry>first-lba x at -le ( addr first-lba )
+ block gpt-part-entry>last-lba x at -le ( addr first-lba last-lba)
+ over - 1+ ( addr first-lba blocks )
+ swap ( addr blocks first-lba )
+ block-size * to part-offset ( addr blocks )
+ 0 0 seek drop ( addr blocks )
+ block-size * read ( size )
+ UNLOOP EXIT
+ THEN
+ seek-pos gpt-part-size + to seek-pos
+ LOOP
+ false
+;
+
+: try-gpt-dos-partition ( -- true|false )
+ get-gpt-partition 0= IF false EXIT THEN
+ block gpt>num-part-entry l at -le dup 0= IF false EXIT THEN
+ 1+ 1 ?DO
+ seek-pos 0 seek drop
+ block gpt-part-size read drop
+ gpt-basic-data-partition? IF
+ debug-disk-label? IF ." GPT BASIC DATA partition found " cr THEN
+ block gpt-part-entry>first-lba x at -le ( first-lba )
+ dup to part-start ( first-lba )
+ block gpt-part-entry>last-lba x at -le ( first-lba last-lba )
+ over - 1+ ( first-lba s1 )
+ block-size * to part-size ( first-lba )
+ block-size * to part-offset ( )
+ 0 0 seek drop
+ block block-size read drop
+ block fat-bootblock? ( true|false )
UNLOOP EXIT
THEN
- seek-pos gpt-part-size i * + to seek-pos
+ seek-pos gpt-part-size + to seek-pos
LOOP
false
;
@@ -490,7 +549,7 @@ AA268B49521E5A8B CONSTANT GPT-PREP-PARTITION-4
debug-disk-label? IF ." Trying CHRP boot " .s cr THEN
1 disk-chrp-boot !
- dup load-chrp-boot-file ?dup 0 <> IF .s cr nip EXIT THEN
+ dup load-chrp-boot-file ?dup 0 <> IF nip EXIT THEN
0 disk-chrp-boot !
debug-disk-label? IF ." Trying GPT boot " .s cr THEN
@@ -590,6 +649,7 @@ AA268B49521E5A8B CONSTANT GPT-PREP-PARTITION-4
: try-partitions ( -- found? )
try-dos-partition IF try-files EXIT THEN
+ try-gpt-dos-partition IF try-files EXIT THEN
\ try-iso9660-partition IF try-files EXIT THEN
\ ... more partition types here...
false
@@ -600,7 +660,7 @@ AA268B49521E5A8B CONSTANT GPT-PREP-PARTITION-4
: close ( -- )
debug-disk-label? IF ." Closing disk-label: block=0x" block u. ." block-size=" block-size .d cr THEN
- block d# 4096 free-mem
+ block block-array-size free-mem
;
--
2.4.3
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