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Line 489... Line 489...
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	rdpr %tstate, %g1
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	rdpr %tstate, %g1
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	andcc %g1, TSTATE_PRIV_BIT, %g0		! if we are not returning to userspace...,
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	andcc %g1, TSTATE_PRIV_BIT, %g0		! if we are not returning to userspace...,
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	bnz 1f					! ...skip restoring userspace windows
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	bnz 1f					! ...skip restoring userspace windows
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	nop
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	nop
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	/*
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	 * Spills and fills will be processed by the {spill,fill}_1_normal
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	 * handlers.
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	 */
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	wrpr %g0, WSTATE_OTHER(0) | WSTATE_NORMAL(1), %wstate
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	rdpr %cwp, %g1
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	rdpr %cwp, %g1
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	rdpr %otherwin, %g2
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	rdpr %otherwin, %g2
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	/*
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	/*
Line 543... Line 549...
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	 * Switch back to the proper current window and adjust
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	 * Switch back to the proper current window and adjust
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	 * OTHERWIN, CANRESTORE, CANSAVE and CLEANWIN.
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	 * OTHERWIN, CANRESTORE, CANSAVE and CLEANWIN.
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	 */
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	 */
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	wrpr %g1, 0, %cwp
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	wrpr %g1, 0, %cwp
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	add %g4, %g2, %g2
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	add %g4, %g2, %g2
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	mov NWINDOW - 2, %g1
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	cmp %g2, NWINDOW - 2
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	bg 2f					! fix the CANRESTORE=NWINDOW-1 anomaly
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	mov NWINDOW - 2, %g1			! use dealy slot for both cases
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	sub %g1, %g2, %g1
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	sub %g1, %g2, %g1
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	wrpr %g0, 0, %otherwin
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	wrpr %g0, 0, %otherwin
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	wrpr %g1, 0, %cansave			! NWINDOW - 2 - CANRESTORE
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	wrpr %g1, 0, %cansave			! NWINDOW - 2 - CANRESTORE
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	wrpr %g2, 0, %canrestore		! OTHERWIN + windows in the buffer
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	wrpr %g2, 0, %canrestore		! OTHERWIN + windows in the buffer
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	wrpr %g2, 0, %cleanwin			! avoid information leak
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	wrpr %g2, 0, %cleanwin			! avoid information leak
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1:
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	restore
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	retry
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	/*
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	/*
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	 * Spills and fills will be processed by the {spill,fill}_1_normal
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	 * We got here in order to avoid inconsistency of the window state registers.
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	 * handlers.
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	 * If the:
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	 *
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	 * 	save %g6, -PREEMPTIBLE_HANDLER_STACK_FRAME_SIZE, %sp
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	 *
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	 * instruction trapped and spilled a register window into the userspace
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	 * window buffer, we have just restored NWINDOW - 1 register windows.
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	 * However, CANRESTORE can be only NWINDOW - 2 at most.
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	 *
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	 * The solution is to manually switch to (CWP - 1) mod NWINDOW
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	 * and set the window state registers so that:
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	 *
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	 * 	CANRESTORE 	= NWINDOW - 2
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	 *	CLEANWIN	= NWINDOW - 2
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	 *	CANSAVE 	= 0
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	 *	OTHERWIN	= 0
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	 *
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	 * The RESTORE isntruction is therfore to be skipped.
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	 */
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	 */
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2:
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	wrpr %g0, 0, %otherwin
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	wrpr %g0, 0, %cansave
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	wrpr %g0, WSTATE_OTHER(0) | WSTATE_NORMAL(1), %wstate
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	wrpr %g1, 0, %canrestore
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	wrpr %g1, 0, %cleanwin
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1:
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	rdpr %cwp, %g1
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	restore
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	dec %g1
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	and %g1, NWINDOW - 1, %g1
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	wrpr %g1, 0, %cwp			! CWP--
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	retry
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	retry