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authorhpa <hpa>2001-12-16 00:03:28 +0000
committerhpa <hpa>2001-12-16 00:03:28 +0000
commit9d0869d27f663580d408e76cb2ea210714dea553 (patch)
tree4106606ef55794780784a35af434a42eb1bcc94b /pxelinux.asm
parentb9f4a599f1bd31369f3f3f49e05d2102ceb295fd (diff)
downloadsyslinux-1.65.tar.gz
syslinux-1.65.tar.xz
syslinux-1.65.zip
Make a valiant, and probably futile, attempt to free memory aftersyslinux-1.65
running the PXE stack.
Diffstat (limited to 'pxelinux.asm')
-rw-r--r--pxelinux.asm115
1 files changed, 110 insertions, 5 deletions
diff --git a/pxelinux.asm b/pxelinux.asm
index 4f5e806a..6df269e6 100644
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -376,6 +376,7 @@ PktTimeout resw 1 ; Timeout for current packet
KernelExtPtr resw 1 ; During search, final null pointer
IPOptionLen resw 1 ; Length of IPOption
LocalBootType resw 1 ; Local boot return code
+RealBaseMem resw 1 ; Amount of DOS memory after freeing
TextAttrBX equ $
TextAttribute resb 1 ; Text attribute for message file
TextPage resb 1 ; Active display page
@@ -476,7 +477,7 @@ _start1:
; Nothing there either. Last-ditch: scan memory
call memory_scan_for_pxe_struct ; !PXE scan
- jnc have_pxe
+ jnc near have_pxe
call memory_scan_for_pxenv_struct ; PXENV+ scan
jnc have_pxenv
@@ -500,12 +501,12 @@ have_pxenv:
mov ax,es
les bx,[es:bx+28h] ; !PXE structure pointer
cmp dword [es:bx],'!PXE'
- je have_pxe
+ je near have_pxe
; Nope, !PXE structure missing despite API 2.1+, or at least
; the pointer is missing. Do a last-ditch attempt to find it.
call memory_scan_for_pxe_struct
- jnc have_pxe
+ jnc near have_pxe
; Otherwise, no dice, use PXENV+ structure
mov bx,si
@@ -518,6 +519,43 @@ old_api: ; Need to use a PXENV+ structure
mov eax,[es:bx+0Ah] ; PXE RM API
mov [PXENVEntry],eax
+ mov si,undi_data_msg ; ***
+ call writestr
+ mov ax,[es:bx+20h]
+ call writehex4
+ call crlf
+ mov si,undi_data_len_msg
+ call writestr
+ mov ax,[es:bx+22h]
+ call writehex4
+ call crlf
+ mov si,undi_code_msg
+ call writestr
+ mov ax,[es:bx+24h]
+ call writehex4
+ call crlf
+ mov si,undi_code_len_msg
+ call writestr
+ mov ax,[es:bx+26h]
+ call writehex4
+ call crlf
+
+ ; Compute base memory size from PXENV+ structure
+ xor esi,esi
+ movzx eax,word [es:bx+20h] ; UNDI data seg
+ cmp ax,[es:bx+24h] ; UNDI code seg
+ ja .use_data
+ mov ax,[es:bx+24h]
+ mov si,[es:bx+26h]
+ jmp short .combine
+.use_data:
+ mov si,[es:bx+22h]
+.combine:
+ shl eax,4
+ add eax,esi
+ shr eax,10 ; Convert to kilobytes
+ mov [RealBaseMem],ax
+
mov si,pxenventry_msg
call writestr
mov ax,[PXENVEntry+2]
@@ -527,12 +565,48 @@ old_api: ; Need to use a PXENV+ structure
mov ax,[PXENVEntry]
call writehex4
call crlf
- jmp short have_entrypoint
+ jmp near have_entrypoint
have_pxe:
mov eax,[es:bx+10h]
mov [PXEEntry],eax
+ mov si,undi_data_msg ; ***
+ call writestr
+ mov eax,[es:bx+2Ah]
+ call writehex8
+ call crlf
+ mov si,undi_data_len_msg
+ call writestr
+ mov ax,[es:bx+2Eh]
+ call writehex4
+ call crlf
+ mov si,undi_code_msg
+ call writestr
+ mov ax,[es:bx+32h]
+ call writehex8
+ call crlf
+ mov si,undi_code_len_msg
+ call writestr
+ mov ax,[es:bx+36h]
+ call writehex4
+ call crlf
+
+ ; Compute base memory size from !PXE structure
+ xor esi,esi
+ mov eax,[es:bx+2Ah]
+ cmp eax,[es:bx+32h]
+ ja .use_data
+ mov eax,[es:bx+32h]
+ mov si,[es:bx+36h]
+ jmp short .combine
+.use_data:
+ mov si,[es:bx+2Eh]
+.combine:
+ add eax,esi
+ shr eax,10
+ mov [RealBaseMem],ax
+
mov si,pxeentry_msg
call writestr
mov ax,[PXEEntry+2]
@@ -4161,7 +4235,8 @@ ack_packet:
;
; unload_pxe:
;
-; This function unloads the PXE and UNDI stacks.
+; This function unloads the PXE and UNDI stacks and unclaims
+; the memory.
;
unload_pxe:
mov di,pxe_udp_close_pkt
@@ -4173,7 +4248,32 @@ unload_pxe:
mov di,pxe_unload_stack_pkt
mov bx,PXENV_UNLOAD_STACK
call far [PXENVEntry]
+ jc .cant_free
+ cmp word [pxe_unload_stack_pkt.status],byte PXENV_STATUS_SUCCESS
+ jne .cant_free
+
+ mov ax,[RealBaseMem]
+ cmp ax,[BIOS_fbm] ; Sanity check
+ jna .cant_free
+
+ ; Check that PXE actually unhooked the INT 1Ah chain
+ movzx ebx,word [4*0x1a]
+ movzx ecx,word [4*0x1a+2]
+ shl ecx,4
+ add ebx,ecx
+ shr ebx,10
+ cmp bx,ax ; Not in range
+ jae .ok
+ cmp bx,[BIOS_fbm]
+ jae .cant_free
+
+.ok:
+ mov [BIOS_fbm],ax
ret
+
+.cant_free:
+ mov si,cant_free_msg
+ jmp writestr
;
; gendotquad
@@ -4786,6 +4886,11 @@ pxeentry_msg db 'PXE entry point found (we hope) at ', 0
pxenventry_msg db 'PXENV entry point found (we hope) at ', 0
trymempxe_msg db 'Scanning memory for !PXE structure... ', 0
trymempxenv_msg db 'Scanning memory for PXENV+ structure... ', 0
+undi_data_msg db 'UNDI data segment at: ',0
+undi_data_len_msg db 'UNDI data segment size: ',0
+undi_code_msg db 'UNDI code segment at: ',0
+undi_code_len_msg db 'UNDI code segment size: ',0
+cant_free_msg db 'Failed to free base memory, sorry...', CR, LF, 0
notfound_msg db 'not found', CR, LF, 0
myipaddr_msg db 'My IP address seems to be ',0
tftpprefix_msg db 'TFTP prefix: ', 0