Make spl7 just clear IF instead of setting the PIC mask

* i386/i386/spl.S (spl7): Just set curr_ipl and cli.
(splx) [MACH_KDB || MACH_TTD]: When curr_ipl is 7, make sure that IF is cleared.
(splx): When staying at ipl7, do not enable interrupts.
(spl) [MACH_KDB || MACH_TTD]: When curr_ipl is 7, make sure that IF is cleared.
(spl): When new ipl is 7, branch to spl7.
* i386/i386/locore.S (TIME_TRAP_UENTRY, TIME_TRAP_SENTRY): Save flags, and
restore them instead of blindly using sti.

2 files changed, 39 insertions, 3 deletions

diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index e1befa7..15715f6 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -119,6 +119,7 @@ LEXT(retry_table_end)			;\
  * Uses %eax, %ebx, %ecx.
  */
 #define	TIME_TRAP_UENTRY \
+	pushf					/* Save flags */	;\
 	cli					/* block interrupts */	;\
 	movl	VA_ETC,%ebx			/* get timer value */	;\
 	movl	CX(EXT(current_tstamp),%edx),%ecx	/* get old time stamp */;\
@@ -131,7 +132,7 @@ LEXT(retry_table_end)			;\
 0:	addl	$(TH_SYSTEM_TIMER-TH_USER_TIMER),%ecx			;\
 						/* switch to sys timer */;\
 	movl	%ecx,CX(EXT(current_timer),%edx)	/* make it current */	;\
-	sti					/* allow interrupts */
+	popf					/* allow interrupts */
 
 /*
  * Update time on system call entry.
@@ -141,6 +142,7 @@ LEXT(retry_table_end)			;\
  * Same as TIME_TRAP_UENTRY, but preserves %eax.
  */
 #define	TIME_TRAP_SENTRY \
+	pushf					/* Save flags */	;\
 	cli					/* block interrupts */	;\
 	movl	VA_ETC,%ebx			/* get timer value */	;\
 	movl	CX(EXT(current_tstamp),%edx),%ecx	/* get old time stamp */;\
@@ -155,7 +157,7 @@ LEXT(retry_table_end)			;\
 0:	addl	$(TH_SYSTEM_TIMER-TH_USER_TIMER),%ecx			;\
 						/* switch to sys timer */;\
 	movl	%ecx,CX(EXT(current_timer),%edx)	/* make it current */	;\
-	sti					/* allow interrupts */
+	popf					/* allow interrupts */
 
 /*
  * update time on user trap exit.
diff --git a/i386/i386/spl.S b/i386/i386/spl.S
index 3c07509..41458ac 100644
--- a/i386/i386/spl.S
+++ b/i386/i386/spl.S
@@ -140,15 +140,35 @@ Entry(splsched)
 Entry(splhigh)
 Entry(splhi)
 ENTRY(spl7)
-	SETIPL(SPL7)
+	/* ipl7 just clears IF */
+	movl	$SPL7,%eax
+	xchgl	EXT(curr_ipl),%eax
+	cli
+	ret
 
 ENTRY(splx)
 	movl	S_ARG0,%edx		/* get ipl */
+
+#if MACH_KDB || MACH_TTD
+	/* First make sure that if we're exitting from ipl7, IF is still cleared */
+	cmpl	$SPL7,EXT(curr_ipl)	/* from ipl7? */
+	jne	0f
+	pushfl
+	popl	%eax
+	testl	$0x200,%eax		/* IF? */
+	jz	0f
+	int3				/* Oops, interrupts got enabled?! */
+
+0:
+#endif	/* MACH_KDB || MACH_TTD */
 	testl	%edx,%edx		/* spl0? */
 	jz	EXT(spl0)		/* yes, handle specially */
 	cmpl	EXT(curr_ipl),%edx	/* same ipl as current? */
 	jne	spl			/* no */
+	cmpl	$SPL7,%edx		/* spl7? */
+	je	1f			/* to ipl7, don't enable interrupts */
 	sti				/* ensure interrupts are enabled */
+1:
 	movl	%edx,%eax		/* return previous ipl */
 	ret
 
@@ -207,6 +227,20 @@ splx_cli:
 	.align	TEXT_ALIGN
 	.globl	spl
 spl:
+#if MACH_KDB || MACH_TTD
+	/* First make sure that if we're exitting from ipl7, IF is still cleared */
+	cmpl	$SPL7,EXT(curr_ipl)	/* from ipl7? */
+	jne	0f
+	pushfl
+	popl	%eax
+	testl	$0x200,%eax		/* IF? */
+	jz	0f
+	int3				/* Oops, interrupts got enabled?! */
+
+0:
+#endif	/* MACH_KDB || MACH_TTD */
+	cmpl	$SPL7,%edx		/* spl7? */
+	je	EXT(spl7)		/* yes, handle specially */
 	movl	EXT(pic_mask)(,%edx,4),%eax
 					/* get PIC mask */
 	cli				/* disable interrupts */