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| author | Warner Losh <imp@FreeBSD.org> | 2023-11-27 22:40:40 +0000 |
|---|---|---|
| committer | Warner Losh <imp@FreeBSD.org> | 2023-11-27 22:45:56 +0000 |
| commit | c596126a5d3d2ee015ee6807b4041efa5b9d9b07 (patch) | |
| tree | b09e12421134ebe0280ee71247e0c71c72f77423 /stand | |
| parent | a5c27819344bfcbdf5ae6a430af9c6ca98b0a249 (diff) | |
| download | src-c596126a5d3d2ee015ee6807b4041efa5b9d9b07.tar.gz src-c596126a5d3d2ee015ee6807b4041efa5b9d9b07.zip | |
pmbr: Only load the first 545k rather than error out
It would be nice to have larger boot partitions for ESPs to live in one
day. It's trivial to carve out 5M 10M or 200M when provisioning, but
logistical issues may make it hard to do it after the fact. So only warn
when the partition is > 545k. If we ever grow the boot loader larger
than that, then it will be responsible for loading the rest anyway.
Sponsored by: Netflix
Reviewed by: tsoome
Differential Revision: https://reviews.freebsd.org/D42774
Diffstat (limited to 'stand')
| -rw-r--r-- | stand/i386/pmbr/pmbr.S | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/stand/i386/pmbr/pmbr.S b/stand/i386/pmbr/pmbr.S index c61acbe261bd..60b26df15720 100644 --- a/stand/i386/pmbr/pmbr.S +++ b/stand/i386/pmbr/pmbr.S @@ -155,8 +155,10 @@ next_boot: addl $1,(%si) # Next LBA mov %es,%ax # Adjust segment for next addw $SECSIZE/16,%ax # sector cmp $0x9000,%ax # Don't load past 0x90000, - jae err_big # 545k should be enough for - mov %ax,%es # any boot code. :) + jb sz_ok # 545k should be enough for + call err_big # any boot code, but warn + mov $0x9000-SECSIZE/16,%ax # and truncate +sz_ok: mov %ax,%es jmp load_boot # # Move to the next partition. If we walk off the end of the sector, load @@ -203,17 +205,21 @@ getdrvparams: # # Various error message entry points. # -err_big: movw $msg_big,%si # "Boot loader too - jmp putstr # large" +err_big: movw $msg_big,%si # "Truncated + call putstr # to 545k" + ret err_pt: movw $msg_pt,%si # "Invalid partition - jmp putstr # table" + call putstr # table" +err_pt.1: jmp err_pt.1 # Await reset err_rd: movw $msg_rd,%si # "I/O error loading - jmp putstr # boot loader" + call putstr # boot loader" + jmp err_pt.1 err_noboot: movw $msg_noboot,%si # "Missing boot - jmp putstr # loader" + call putstr # loader" + jmp err_pt.1 # # Output an ASCIZ string to the console via the BIOS. # @@ -223,9 +229,9 @@ putstr.0: movw $0x7,%bx # Page:attribute putstr: lodsb # Get character testb %al,%al # End of string? jnz putstr.0 # No -putstr.1: jmp putstr.1 # Await reset + ret -msg_big: .asciz "Boot loader too large" +msg_big: .asciz "Loaded only 545k" msg_pt: .asciz "Invalid partition table" msg_rd: .asciz "I/O error loading boot loader" msg_noboot: .asciz "Missing boot loader" |