diff options
| author | Emrion <kmachine@free.fr> | 2021-07-13 20:37:59 +0000 |
|---|---|---|
| committer | Warner Losh <imp@FreeBSD.org> | 2021-07-13 21:40:44 +0000 |
| commit | 0ca9f1d4a3b772036309fb1c14262ec77c674c5d (patch) | |
| tree | d4fe7cd9b786fd512bda7f13869c3289873e6161 | |
| parent | a065ccb2804fae834a7c66e29b726ea3dbbceace (diff) | |
| download | src-0ca9f1d4a3b772036309fb1c14262ec77c674c5d.tar.gz src-0ca9f1d4a3b772036309fb1c14262ec77c674c5d.zip | |
Fix pmbr issues > 2TB
These issues have low impact because they require precise circumstances
to trigger one of them. The disk must be > 2 TiB in size and either:
- The primary GPT header is dammaged.
- The freebsd-boot partiton is located farther than the first 2 TiB of
the disc and one of its sectors takes place at a lba value that makes
the higher 32 bits of this very value change.
Errors and corrections folow:
- decl and incl don't affect CF, so replace with subl/addl $1
- repe uses %cx, so move size to it with movw
- moving a 64-bit value with %cx of 2 (should be 4) so addresses
> 2TB will work.
PR: 233180
Reviewed by: imp@ (applied patch using description in bug)
Differential Revision: https://reviews.freebsd.org/D31100
| -rw-r--r-- | stand/i386/pmbr/pmbr.S | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/stand/i386/pmbr/pmbr.S b/stand/i386/pmbr/pmbr.S index 1a758812edd3..c394835757af 100644 --- a/stand/i386/pmbr/pmbr.S +++ b/stand/i386/pmbr/pmbr.S @@ -114,8 +114,9 @@ main.2b: cmpb $1,%dh # Reading primary? main.3: movb $0,%dh # %dh := 0 (reading backup) movw $DPBUF+DPBUF_SEC,%si # %si = last sector + 1 movw $lba,%di # %di = $lba -main.3a: decl (%si) # 0x0(%si) = last sec (0-31) - movw $2,%cx +main.3a: subl $1, (%si) # 0x0(%si) = last sec (0-31) + sbbl $0, 4(%si) + movw $4,%cx rep movsw # $lastsec--, copy it to $lba jmp main.2a # Read the next sector @@ -128,7 +129,7 @@ load_part: movw $GPT_ADDR+GPT_PART_LBA,%si call read scan: movw %bx,%si # Compare partition UUID movw $boot_uuid,%di # with FreeBSD boot UUID - movb $0x10,%cl + movw $0x10,%cx repe cmpsb jnz next_part # Didn't match, next partition # @@ -150,7 +151,7 @@ load_boot: push %si # Save %si jnz next_boot mov %bx,%es # Reset %es to zero jmp LOAD # Jump to boot code -next_boot: incl (%si) # Next LBA +next_boot: addl $1,(%si) # Next LBA adcl $0,4(%si) mov %es,%ax # Adjust segment for next addw $SECSIZE/16,%ax # sector @@ -171,7 +172,7 @@ next_part: decl GPT_ADDR+GPT_NPART # Was this the last partition? addw %ax,%bx # Next partition cmpw $PART_ADDR+0x200,%bx # Still in sector? jb scan - incl GPT_ADDR+GPT_PART_LBA # Next sector + addl $1, GPT_ADDR+GPT_PART_LBA # Next sector adcl $0,GPT_ADDR+GPT_PART_LBA+4 jmp load_part # |