More tweaks to allow bigger stack/heap, and boot protocol adjustments

Seems the su_heapend field was never set up right; also sanitize the
way the pre-2.02 command line is handled.

diff --git a/com32/lib/syslinux/load_linux.c b/com32/lib/syslinux/load_linux.c
index d2ad264..13a0fa0 100644 (file)
--- a/com32/lib/syslinux/load_linux.c
+++ b/com32/lib/syslinux/load_linux.c
@@ -190,7 +190,7 @@ int syslinux_boot_linux(void *kernel_buf, size_t kernel_size,
   if (hdr.version < 0x0202 || !(hdr.loadflags & 0x01))
     cmdline_offset = (0x9ff0 - cmdline_size) & ~15;
   else
-    cmdline_offset = (0xfff0 - cmdline_size) & ~15;
+    cmdline_offset = 0x10000;
 
   real_mode_size = (hdr.setup_sects+1) << 9;
   real_mode_base = (hdr.loadflags & LOAD_HIGH) ? 0x10000 : 0x90000;

diff --git a/kernel.inc b/kernel.inc
index d72ce2f..b4d356a 100644 (file)
--- a/kernel.inc
+++ b/kernel.inc
@@ -57,9 +57,9 @@ su_pad1               resw 1                  ; 0226
 su_cmd_line_ptr        resd 1                  ; 0228
 su_ramdisk_max resd 1                  ; 022C
                resb (0e000h-12)-($-$$) ; Were bootsect.S puts it...
-linux_stack    equ $                   ; BFF4
+linux_stack    equ $                   ; DFF4
 linux_fdctab   resb 12
-cmd_line_here  equ $                   ; C000 Should be out of the way
+cmd_line_here  equ $                   ; E000 Should be out of the way
                endstruc
 
 ;
@@ -71,7 +71,7 @@ CMD_MAGIC     equ 0A33Fh              ; Command line magic
 ; If we're loading the command line old-style, we need a smaller
 ; heap.
 ;
-old_cmd_line_here equ 9000h
+old_cmd_line_here equ 9800h
 old_linux_fdctab  equ old_cmd_line_here-12
 old_linux_stack   equ old_linux_fdctab
 

diff --git a/runkernel.inc b/runkernel.inc
index 22e8e69..04d3bb1 100644 (file)
--- a/runkernel.inc
+++ b/runkernel.inc
@@ -214,7 +214,8 @@ prepare_header:
                jb old_kernel                   ; Old kernel, load low
                cmp ax,0201h                    ; Version 2.01+?
                 jb new_kernel                   ; If 2.00, skip this step
-                mov word [es:su_heapend],linux_stack   ; Set up the heap
+               ; Set up the heap (assuming loading high for now)
+                mov word [es:su_heapend],linux_stack-512
                 or byte [es:su_loadflags],80h  ; Let the kernel know we care
                cmp ax,0203h                    ; Version 2.03+?
                jb new_kernel                   ; Not 2.03+
@@ -319,6 +320,7 @@ nk_noinitrd:
 ; capable of starting their setup from a different address.
 ;
                mov ax,real_mode_seg
+               mov es,ax
                mov fs,ax
 
 ;
@@ -327,34 +329,38 @@ nk_noinitrd:
 ; setup doesn't.
 ;
                cli                             ; In case of hooked interrupts
+               mov dx,[fs:su_version]          ; cmdline protocol version
                test byte [LoadFlags],LOAD_HIGH
                jz need_high_cmdline
-               cmp word [fs:su_version],0202h  ; Support new cmdline protocol?
+               cmp dx,0202h                    ; Support new cmdline protocol?
                jb need_high_cmdline
                ; New cmdline protocol
                ; Store 32-bit (flat) pointer to command line
-               mov dword [fs:su_cmd_line_ptr],(real_mode_seg << 4) + cmd_line_here
+               ; This is the "high" location, since we have bzImage
+               mov dword [fs:su_cmd_line_ptr],(real_mode_seg << 4)+cmd_line_here
                jmp in_proper_place
 
 need_high_cmdline:
 ;
-; Copy command line to 90000h (old style) -- this happens either if
-; we have a zImage kernel or the protocol is less than 2.02.
+; Copy command line down to fit in high conventional memory
+; -- this happens if we have a zImage kernel or the protocol
+; is less than 2.02.
 ;
-               mov ax,9000h                    ; Note AL <- 0
-               mov es,ax
                mov si,cmd_line_here
                mov di,old_cmd_line_here
                mov [fs:kern_cmd_magic],word CMD_MAGIC ; Store magic
                mov [fs:kern_cmd_offset],di     ; Store pointer
                mov word [HeapEnd],old_linux_stack
                mov ax,255                      ; Max cmdline limit
-               cmp word [fs:su_version],0201h
+               cmp dx,0201h
                jb .adjusted
                ; Protocol 2.01+
-               mov word [fs:su_heapend],old_linux_stack
+               mov word [fs:su_heapend],old_linux_stack-512
                jbe .adjusted
                ; Protocol 2.02+
+               ; Note that the only reason we would end up here is
+               ; because we have a zImage, so we anticipate the move
+               ; to 90000h already...
                mov dword [fs:su_cmd_line_ptr],0x90000+old_cmd_line_here
                mov ax,4095                     ; 2.02+ allow a higher limit
 .adjusted:
@@ -366,9 +372,10 @@ need_high_cmdline:
 .len_ok:
                fs rep movsb
                stosb                           ; Final null, note AL=0 already
-
-               push fs
-               pop es
+               cmp dx,0200h
+               jb .nomovesize
+               mov [es:su_movesize],di         ; Tell the kernel what to move
+.nomovesize:
 
                test byte [LoadFlags],LOAD_HIGH
                jnz in_proper_place             ; If high load, we're done
@@ -380,9 +387,9 @@ need_high_cmdline:
 ;
                mov ax,9000h
                mov es,ax
-               mov cx,[SetupSecs]
-               inc cx                          ; Setup + boot sector
-               shl cx,7                        ; Sectors -> dwords
+               mov cx,di                       ; == su_movesize (from above)
+               add cx,3                        ; Round up
+               shr cx,2                        ; Convert to dwords
                xor si,si
                xor di,di
                fs rep movsd                    ; Copy setup + boot sector
@@ -403,7 +410,8 @@ need_high_cmdline:
                xor eax,eax
                rep stosd                       ; Clear region
 ;
-; Copy the kernel down to the "low" location
+; Copy the kernel down to the "low" location (the kernel will then
+; move itself again, sigh.)
 ;
                mov ecx,[KernelSize]
                mov esi,100000h
@@ -441,7 +449,8 @@ root_not_floppy:
 %endif
 ;
 ; Linux wants the floppy motor shut off before starting the kernel,
-; at least bootsect.S seems to imply so.
+; at least bootsect.S seems to imply so.  If we don't load the floppy
+; driver, this is *definitely* so!
 ;
 kill_motor:
                xor ax,ax
@@ -466,7 +475,9 @@ kill_motor:
                mov fs,bx
                mov gs,bx
                mov ss,bx
-               mov sp,[cs:HeapEnd]
+               mov sp,strict word linux_stack
+               ; Point HeapEnd to the immediate of the instruction above
+HeapEnd                equ $-2                 ; Self-modifying code!  Fun!
 
 ;
 ; We're done... now RUN THAT KERNEL!!!!
@@ -638,8 +649,6 @@ no_high_mem:                                        ; Error routine
                 ret
 
                section .data
-               alignb 2
-HeapEnd                dw linux_stack          ; Default end of heap
 boot_image      db 'BOOT_IMAGE='
 boot_image_len  equ $-boot_image