Always make the initrd fit under the 0x3f000000 mark imposed by unmodified

Linux kernels.

diff --git a/ldlinux.asm b/ldlinux.asm
index 25b8f35..8e5d102 100644 (file)
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -27,10 +27,12 @@
 ; ****************************************************************************
 
 ;
-; Some semi-configurable constants... change on your own risk
+; Some semi-configurable constants... change on your own risk.  Most are imposed
+; by the kernel.
 ;
 max_cmd_len    equ 255                 ; Must be odd; 255 is the kernel limit
 retry_count    equ 6                   ; How patient are we with the disk?
+HIGHMEM_MAX    equ 03f000000h          ; Highest address for an initrd
 
 ;
 ; Should be updated with every release to avoid bootsector/SYS file mismatch
@@ -1861,6 +1863,11 @@ new_kernel:
                add ax,dx
                mov [InitRDClust],ax            ; Ramdisk clusters
                mov edx,[HighMemSize]           ; End of memory
+               mov eax,HIGHMEM_MAX             ; Limit imposed by kernel
+               cmp edx,eax
+               jna memsize_ok
+               mov edx,eax                     ; Adjust to fit inside limit
+memsize_ok:
                sub edx,[es:su_ramdisklen]      ; Subtract size of ramdisk
                 xor dx,dx                      ; Round down to 64K boundary
                 mov [InitRDat],edx             ; Load address