Diff of /trunk/mkinitrd-magellan/isolinux/cpuinit.inc

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	revision 1132 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 1133 by niro, Thu Aug 19 09:50:43 2010 UTC
#	Line 1	Line 1
	;; $Id: cpuinit.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
1	;; -----------------------------------------------------------------------	;; -----------------------------------------------------------------------
2	;;	;;
3	;;   Copyright 1994-2002 H. Peter Anvin - All Rights Reserved	;;   Copyright 1994-2008 H. Peter Anvin - All Rights Reserved
4		;;   Copyright 2010 Intel Corporation; author: H. Peter Anvin
5	;;	;;
6	;;   This program is free software; you can redistribute it and/or modify	;;   This program is free software; you can redistribute it and/or modify
7	;;   it under the terms of the GNU General Public License as published by	;;   it under the terms of the GNU General Public License as published by
#	Line 13	Line 13
13
14	;;	;;
15	;; cpuinit.inc	;; cpuinit.inc
16	;;	;;
17	;; CPU-dependent initialization and related checks.	;; CPU-dependent initialization and related checks.
18	;;	;;
19
#	Line 35  dosram_k equ (real_mode_seg+0x1000) >> 6	Line 35  dosram_k equ (real_mode_seg+0x1000) >> 6
35	cmp ax,dosram_k	cmp ax,dosram_k
36	jae enough_ram	jae enough_ram
37	mov si,err_noram	mov si,err_noram
38	call writestr	call writestr_early
39	jmp kaboom	jmp kaboom
40	enough_ram:	enough_ram:
41	skip_checks:	skip_checks:
42
43	;	;
44	; Initialize the bcopy32 code in low memory	; Detect old versions Xen HVM and disable halt
45	;	; Xen HVM older than version 3.3 might be using vmxassist, which breaks
46	mov si,section..bcopy32.start	; if HLT is executed in real mode.
	mov di,__bcopy_start
	mov cx,__bcopy_size >> 2
	rep movsd
	;
	; Check if we're 386 (as opposed to 486+); if so we need to blank out
	; the WBINVD instruction
47	;	;
48	; We check for 486 by setting EFLAGS.AC	; Note: in Syslinux 4, we should probably just execute the HLT in
49		; protected mode instead.
50	;	;
51	%if DO_WBINVD	check_xen:
52	pushfd ; Save the good flags	pushfd
53	pushfd	pushfd
54	pop eax	pop eax
55	mov ebx,eax	mov edx,eax
56	xor eax,(1 << 18) ; AC bit	xor eax,(1 << 21) ; ID flag
57	push eax	push eax
58	popfd	popfd
59	pushfd	pushfd
60	pop eax	pop eax
61	popfd ; Restore the original flags	popfd
62	xor eax,ebx	xor eax,edx
63	jnz is_486	and eax,(1 << 21)
64	;	jz .not_xen ; No CPUID
65	; 386 - Looks like we better blot out the WBINVD instruction
66	;	xor ebx,ebx
67	mov byte [try_wbinvd],0c3h ; Near RET	xor ecx,ecx
68	is_486:	xor edx,edx
69	%endif ; DO_WBINVD	mov eax,0x40000000
70		cpuid
71		cmp ebx,"XenV"
72		jne .not_xen
73		cmp ecx,"MMXe"
74		jne .not_xen
75		cmp edx,"nVMM"
76		jne .not_xen
77
78		; We're on Xen...
79		mov eax,0x40000001
80		cpuid
81		cmp eax,0x00030003
82		jae .not_xen ; Xen >= 3.3, not affected
83
84		; We may be using vmxassist, so disable HLT
85		mov byte [ForceNoHalt],1
86
87		.not_xen:
88
89		section .data
90		err_noram db 'It appears your computer has less than '
91		asciidec dosram_k
92		db 'K of low ("DOS")'
93		db CR, LF
94		db 'RAM.  Linux needs at least this amount to boot.  If you get'
95		db CR, LF
96		db 'this message in error, hold down the Ctrl key while'
97		db CR, LF
98		db 'booting, and I will take your word for it.', CR, LF, 0
99		section .text

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