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Fixed checking for VM86 mode in doreti which I broke in rev.1.30. Only

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the case of VM86 calls from the kernel was broken, so this bug was not
a security hole.

PR:		36710
Submitted by:	David Xu <davidx@viasoft.com.cn> (version for RELENG_4)
MFC after:	3 days
This commit is contained in:
Bruce Evans 2002-05-05 03:19:48 +00:00
parent 9104507502
commit f318190a01
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=96051
1 changed files with 12 additions and 6 deletions
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18
sys/i386/isa/ipl.s
View File

@ -57,13 +57,19 @@
doreti:
FAKE_MCOUNT(bintr) /* init "from" bintr -> doreti */
doreti_next:
/* Check if ASTs can be handled now. */
/*
* Check if ASTs can be handled now. PSL_VM must be checked first
* since segment registers only have an RPL in non-VM86 mode.
*/
testl $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */
jz doreti_notvm86
cmpl $1,in_vm86call /* are we in a vm86 call? */
jne doreti_ast /* can handle ASTs now if not */
jmp doreti_exit
doreti_notvm86:
testb $SEL_RPL_MASK,TF_CS(%esp) /* are we in user mode? */
jne doreti_ast /* yes, do it now. */
testl $PSL_VM,TF_EFLAGS(%esp) /* kernel mode */
je doreti_exit /* and not VM86 mode, defer */
cmpl $1,in_vm86call /* are we in a VM86 call? */
je doreti_exit /* no, defer */
jz doreti_exit /* can't handle ASTs now if not */
doreti_ast:
/*