[OpenBIOS] [PATCH 3/4] SPARC64: defer set_trap_table effect until CIF exit

[Mark Cave-Ayland]

Since OpenBIOS invokes window fill/spill traps during normal operation, make
sure that we defer setting the client trap table until we return control
back to the client.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland at ilande.co.uk>
---
 openbios-devel/arch/sparc64/call-client.S |   14 +++++++++++++-
 openbios-devel/arch/sparc64/openbios.c    |    8 ++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/openbios-devel/arch/sparc64/call-client.S b/openbios-devel/arch/sparc64/call-client.S
index 18de704..47d937f 100644
--- a/openbios-devel/arch/sparc64/call-client.S
+++ b/openbios-devel/arch/sparc64/call-client.S
@@ -1,4 +1,4 @@
-	.globl	sparc64_of_client_interface
+	.globl	sparc64_of_client_interface, client_tba
 
 	.data
 	.align	8
@@ -8,6 +8,8 @@ openbios_stack:
 
 client_stack:
 	.xword	0
+client_tba:
+	.xword	0
 
 	.text
 	.align	4
@@ -35,6 +37,11 @@ sparc64_of_client_interface:
 	stx	%g6, [%sp + 2047 + 40]
 	stx	%g7, [%sp + 2047 + 48]
 
+	/* Save client trap table */
+	setx	client_tba, %g6, %g7
+	rdpr	%tba, %g6
+	stx	%g6, [%g7]
+
 	/* Save existing stack and move to openbios stack */
 	setx	client_stack, %g6, %g7
 	stx	%sp, [%g7]
@@ -54,6 +61,11 @@ sparc64_of_client_interface:
 	setx	client_stack, %g6, %g7
 	ldx	[%g7], %sp
 
+	/* Restore client trap table */
+	setx	client_tba, %g6, %g7
+	ldx	[%g7], %g6
+	wrpr	%g6, %tba
+
 	/* Restore globals */
 	ldx	[%sp + 2047 + 0], %g1
 	ldx	[%sp + 2047 + 8], %g2
diff --git a/openbios-devel/arch/sparc64/openbios.c b/openbios-devel/arch/sparc64/openbios.c
index 9ce3e53..9cc1ac2 100644
--- a/openbios-devel/arch/sparc64/openbios.c
+++ b/openbios-devel/arch/sparc64/openbios.c
@@ -91,14 +91,18 @@ struct cpudef {
 /*
   ( addr -- ? )
 */
+
+extern volatile uint64_t client_tba;
+
 static void
 set_trap_table(void)
 {
     unsigned long addr;
 
     addr = POP();
-    asm("wrpr %0, %%tba\n"
-        : : "r" (addr));
+
+    /* Update client_tba to be updated on CIF exit */
+    client_tba = addr;
 }
 
 /* Reset control register is defined in 17.2.7.3 of US IIi User Manual */
-- 
1.7.10.4