[OpenBIOS] [commit] r1302 - trunk/openbios-devel/arch/sparc64

Fri May 23 14:01:51 CEST 2014

Author: mcayland
Date: Fri May 23 14:01:51 2014
New Revision: 1302
URL: http://tracker.coreboot.org/trac/openbios/changeset/1302

Log:
SPARC64: preserve window state when invoking CIF functions

Members of the *BSD family have a restriction that no window spill/fill traps
can occur in the short time between calling SUNW,set-trap-table in OF and
returning back to the caller.

In order to ensure we minimise window spill/fill traps, preserve the entire
window state across the CIF calls (probably similar to OBP) to ensure that
we don't breach this restriction.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>

Modified:
   trunk/openbios-devel/arch/sparc64/call-client.S

Modified: trunk/openbios-devel/arch/sparc64/call-client.S
==============================================================================

--- trunk/openbios-devel/arch/sparc64/call-client.S	Fri May 23 14:01:43 2014	(r1301)
+++ trunk/openbios-devel/arch/sparc64/call-client.S	Fri May 23 14:01:51 2014	(r1302)
@@ -1,5 +1,153 @@
 	.globl	sparc64_of_client_interface, client_tba
 
+
+/*
+ * SAVE_WINDOW_STATE and RESTORE_WINDOW_STATE are used to ensure
+ * that the CPU window state is preserved across CIF calls. This is
+ * to workaround a *BSD restriction that window fill/spill traps must
+ * be minimised during trap table takeover, and likely emulates the
+ * behaviour of OBP.
+ */
+
+#define SAVE_WINDOW_STATE(type) \
+	setx	client_window, %g6, %g1; \
+	rdpr	%cwp, %g7; \
+	stx	%g7, [%g1]; \
+	rdpr	%cansave, %g7; \
+	stx	%g7, [%g1 + 0x8]; \
+	rdpr	%canrestore, %g7; \
+	stx	%g7, [%g1 + 0x10]; \
+	rdpr	%otherwin, %g7; \
+	stx	%g7, [%g1 + 0x18]; \
+	rdpr	%wstate, %g7; \
+	stx	%g7, [%g1 + 0x20]; \
+	rdpr	%cleanwin, %g7; \
+	stx	%g7, [%g1 + 0x28]; \
+	\
+	stx	%o0, [%g1 + 0x30]; \
+	stx	%o1, [%g1 + 0x38]; \
+	stx	%o2, [%g1 + 0x40]; \
+	stx	%o3, [%g1 + 0x48]; \
+	stx	%o4, [%g1 + 0x50]; \
+	stx	%o5, [%g1 + 0x58]; \
+	stx	%o6, [%g1 + 0x60]; \
+	stx	%o7, [%g1 + 0x68]; \
+	\
+	rdpr	%pstate, %g7; \
+	stx	%g7, [%g1 + 0x70]; \
+	rd	%y, %g7; \
+	stx	%g7, [%g1 + 0x78]; \
+	rd	%fprs, %g7; \
+	stx	%g7, [%g1 + 0x80]; \
+	\
+	/* Now iterate through all of the windows saving all l and i registers */ \
+	add	%g1, 0x90, %g5; \
+	\
+	/* Get the number of windows in %g6 */ \
+	rdpr	%ver, %g6; \
+	and	%g6, 0xf, %g6; \
+	inc	%g6; \
+	\
+save_cpu_window_##type: \
+	deccc	%g6; \
+	wrpr	%g6, %cwp; \
+	stx	%l0, [%g5]; \
+	stx	%l1, [%g5 + 0x8]; \
+	stx	%l2, [%g5 + 0x10]; \
+	stx	%l3, [%g5 + 0x18]; \
+	stx	%l4, [%g5 + 0x20]; \
+	stx	%l5, [%g5 + 0x28]; \
+	stx	%l6, [%g5 + 0x30]; \
+	stx	%l7, [%g5 + 0x38]; \
+	stx	%i0, [%g5 + 0x40]; \
+	stx	%i1, [%g5 + 0x48]; \
+	stx	%i2, [%g5 + 0x50]; \
+	stx	%i3, [%g5 + 0x58]; \
+	stx	%i4, [%g5 + 0x60]; \
+	stx	%i5, [%g5 + 0x68]; \
+	stx	%i6, [%g5 + 0x70]; \
+	stx	%i7, [%g5 + 0x78]; \
+	bne	save_cpu_window_##type; \
+	 add	%g5, 0x80, %g5; \
+	\
+	/* For 8 windows with 16 registers to save in the window, memory required \
+	is 16*8*8 = 0x400 bytes */ \
+	\
+	/* Now we should be in window 0 so update the other window registers */ \
+	rdpr	%ver, %g6; \
+	and	%g6, 0xf, %g6; \
+	dec	%g6; \
+	wrpr	%g6, %cansave; \
+	\
+	wrpr	%g0, %cleanwin; \
+	wrpr	%g0, %canrestore; \
+	wrpr	%g0, %otherwin;
+
+
+#define RESTORE_WINDOW_STATE(type) \
+	setx	client_window, %g6, %g1; \
+	\
+	/* Get the number of windows in %g6 */ \
+	rdpr	%ver, %g6; \
+	and	%g6, 0xf, %g6; \
+	inc	%g6; \
+	\
+	/* Now iterate through all of the windows restoring all l and i registers */ \
+	add	%g1, 0x90, %g5; \
+	\
+restore_cpu_window_##type: \
+	deccc	%g6; \
+	wrpr	%g6, %cwp; \
+	ldx	[%g5], %l0; \
+	ldx	[%g5 + 0x8], %l1; \
+	ldx	[%g5 + 0x10], %l2; \
+	ldx	[%g5 + 0x18], %l3; \
+	ldx	[%g5 + 0x20], %l4; \
+	ldx	[%g5 + 0x28], %l5; \
+	ldx	[%g5 + 0x30], %l6; \
+	ldx	[%g5 + 0x38], %l7; \
+	ldx	[%g5 + 0x40], %i0; \
+	ldx	[%g5 + 0x48], %i1; \
+	ldx	[%g5 + 0x50], %i2; \
+	ldx	[%g5 + 0x58], %i3; \
+	ldx	[%g5 + 0x60], %i4; \
+	ldx	[%g5 + 0x68], %i5; \
+	ldx	[%g5 + 0x70], %i6; \
+	ldx	[%g5 + 0x78], %i7; \
+	bne	restore_cpu_window_##type; \
+	 add	%g5, 0x80, %g5; \
+	\
+	/* Restore the window registers to their original value */ \
+	ldx	[%g1], %g7; \
+	wrpr	%g7, %cwp; \
+	ldx	[%g1 + 0x8], %g7; \
+	wrpr	%g7, %cansave; \
+	ldx	[%g1 + 0x10], %g7; \
+	wrpr	%g7, %canrestore; \
+	ldx	[%g1 + 0x18], %g7; \
+	wrpr	%g7, %otherwin; \
+	ldx	[%g1 + 0x20], %g7; \
+	wrpr	%g7, %wstate; \
+	ldx	[%g1 + 0x28], %g7; \
+	wrpr	%g7, %cleanwin; \
+	\
+	ldx	[%g1 + 0x30], %o0; \
+	ldx	[%g1 + 0x38], %o1; \
+	ldx	[%g1 + 0x40], %o2; \
+	ldx	[%g1 + 0x48], %o3; \
+	ldx	[%g1 + 0x50], %o4; \
+	ldx	[%g1 + 0x58], %o5; \
+	ldx	[%g1 + 0x60], %o6; \
+	ldx	[%g1 + 0x68], %o7; \
+	\
+	ldx	[%g1 + 0x70], %g7; \
+	wrpr	%g7, %pstate; \
+	ldx	[%g1 + 0x78], %g7; \
+	wr	%g7, 0, %y; \
+	ldx	[%g1 + 0x80], %g7; \
+	wr	%g7, 0, %fprs
+
+
 	.data
 	.align	8
 
@@ -10,6 +158,9 @@
 	.xword	0
 client_tba:
 	.xword	0
+client_window:
+	.skip	2048
+
 
 	.text
 	.align	4
@@ -23,8 +174,6 @@
 */
 
 sparc64_of_client_interface:
-	/* make sure caller's windows are on caller's stack */
-	flushw
 
 	/* Save globals on callers stack */
 	add	%sp, -56, %sp
@@ -42,20 +191,26 @@
 	rdpr	%tba, %g6
 	stx	%g6, [%g7]
 
-	/* Save existing stack and move to openbios stack */
+	/* Save existing stack */
 	setx	client_stack, %g6, %g7
 	stx	%sp, [%g7]
+
+	/* Save windows */
+	SAVE_WINDOW_STATE(cif)
+
+	/* Move to OpenBIOS stack */
 	setx	openbios_stack - 2047 - 192, %g6, %g7
 	mov	%g7, %sp
 
 	/* Call client inteface */
-	save	%sp, -192, %sp
-
 	call of_client_interface
-	 mov %i0, %o0
+	 ldx	[%g1 + 0x30], %o0
+
+	setx	client_window, %g6, %g1
+	stx	%o0, [%g1 + 0x30]
 
-	mov	%o0, %i0
-	restore	%sp, 192, %sp
+	/* Restore windows */
+	RESTORE_WINDOW_STATE(cif)
 
 	/* Restore stack */
 	setx	client_stack, %g6, %g7

