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MFC r322667,r322706:

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Improve i386 #UD low-level kdtrace hook.

Approved by:	re (marius)
This commit is contained in:
Konstantin Belousov 2017-08-21 15:44:57 +00:00
parent d56bc0ab75
commit 697d4a095f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/stable/10/; revision=322755
1 changed files with 15 additions and 7 deletions
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22
sys/i386/i386/exception.s
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@ -185,21 +185,29 @@ calltrap:
#ifdef KDTRACE_HOOKS
SUPERALIGN_TEXT
IDTVEC(ill)
/* Check if there is no DTrace hook registered. */
cmpl $0,dtrace_invop_jump_addr
/*
* Check if a DTrace hook is registered. The default (data) segment
* cannot be used for this since %ds is not known good until we
* verify that the entry was from kernel mode.
*/
cmpl $0,%ss:dtrace_invop_jump_addr
je norm_ill
/* Check if this is a user fault. */
cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */
/* If so, just handle it as a normal trap. */
/*
* Check if this is a user fault. If so, just handle it as a normal
* trap.
*/
cmpl $GSEL_KPL, 4(%esp) /* Check the code segment */
jne norm_ill
testl $PSL_VM, 8(%esp) /* and vm86 mode. */
jnz norm_ill
/*
* This is a kernel instruction fault that might have been caused
* by a DTrace provider.
*/
pushal /* Push all registers onto the stack. */
pushal
cld
/*
* Set our jump address for the jump back in the event that