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| author | H. Peter Anvin <hpa@linux.intel.com> | 2011-04-05 14:07:32 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2011-04-05 14:07:32 -0700 |
| commit | b5f98decd092f6358043ff57e18383268b12c1f9 (patch) | |
| tree | 0a2cb6578ca72c757d06d2926e7f99fb91b0ac0a /core | |
| parent | 993ffbac4aa266d83602f736a51450345ef92314 (diff) | |
| download | syslinux-b5f98decd092f6358043ff57e18383268b12c1f9.tar.gz syslinux-b5f98decd092f6358043ff57e18383268b12c1f9.tar.xz syslinux-b5f98decd092f6358043ff57e18383268b12c1f9.zip | |
core: Move sector 1 to address 0x8000 so it is aligned
Move sector 1 to 0x8000, so that it will be sector-aligned no matter
what the sector size is (well, as long as it is <= 32K). This avoids
potential conflicts between the 64K "seams" and the sector size.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'core')
| -rw-r--r-- | core/Makefile | 2 | ||||
| -rw-r--r-- | core/diskboot.inc | 2 | ||||
| -rw-r--r-- | core/diskstart.inc | 14 |
3 files changed, 13 insertions, 5 deletions
diff --git a/core/Makefile b/core/Makefile index 33ad7e95..e89c419a 100644 --- a/core/Makefile +++ b/core/Makefile @@ -109,7 +109,7 @@ ldlinux.bss: ldlinux.bin dd if=$< of=$@ bs=512 count=1 ldlinux.sys: ldlinux.bin - dd if=$< of=$@ bs=512 skip=1 + dd if=$< of=$@ bs=512 skip=2 codepage.cp: ../codepage/$(CODEPAGE).cp cp -f $< $@ diff --git a/core/diskboot.inc b/core/diskboot.inc index 68672e4a..141986e8 100644 --- a/core/diskboot.inc +++ b/core/diskboot.inc @@ -278,7 +278,7 @@ Sect1Ptr1 equ $-4 cmp dword [ldlinux_magic+4],LDLINUX_MAGIC^HEXDATE jne kaboom - ; Go for it! This also normalizes CS:IP. + ; Go for it! jmp ldlinux_ent ; diff --git a/core/diskstart.inc b/core/diskstart.inc index 71cdaee5..01248534 100644 --- a/core/diskstart.inc +++ b/core/diskstart.inc @@ -23,6 +23,14 @@ Sect1Ptr1_VAL equ 0xfeedface %include "diskboot.inc" ; =========================================================================== +; Padding after the (minimum) 512-byte boot sector so that the rest of +; the file has aligned sectors, even if they are larger than 512 bytes. +; =========================================================================== + + section .init +align_pad zb 512 + +; =========================================================================== ; Start of LDLINUX.SYS ; =========================================================================== @@ -424,10 +432,10 @@ safedumpregs: rl_checkpt equ $ ; Must be <= 8000h -rl_checkpt_off equ ($-$$) +rl_checkpt_off equ $-ldlinux_sys %ifndef DEPEND - %if rl_checkpt_off > 3F6h ; Need one extent - %assign rl_checkpt_overflow rl_checkpt_off - 3F6h + %if rl_checkpt_off > 512-10 ; Need minimum one extent + %assign rl_checkpt_overflow rl_checkpt_off - (512-10) %error Sector 1 overflow by rl_checkpt_overflow bytes %endif %endif |