[PATCH v2 4/5] cpukit/microblaze: Clarify interrupt frame usage

[Kinsey Moore]

Avoid use of magic numbers in favor of named constants and add MSR to
the interrupt frame so that thread dispatch can occur on exceptions as
well.
---
 .../microblaze_fpga/start/_interrupt_handler.S   |  4 +++-
 cpukit/score/cpu/microblaze/cpu_asm.S            | 16 ++++++++++++----
 .../cpu/microblaze/include/rtems/score/cpuimpl.h |  3 ++-
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/bsps/microblaze/microblaze_fpga/start/_interrupt_handler.S b/bsps/microblaze/microblaze_fpga/start/_interrupt_handler.S
index b817503922..c24807c3e0 100644
--- a/bsps/microblaze/microblaze_fpga/start/_interrupt_handler.S
+++ b/bsps/microblaze/microblaze_fpga/start/_interrupt_handler.S
@@ -31,6 +31,8 @@
 
 */
 
+#include <rtems/score/cpuimpl.h>
+
 	.text
 	.globl _interrupt_handler    # Interrupt Handler Label
 	.align 2
@@ -41,7 +43,7 @@
 	nop
 #else /* __rtems__ */
 	/* Subtract stack frame */
-	addik r1, r1, -52
+	addik r1, r1, -(CPU_INTERRUPT_FRAME_SIZE)
 
 	swi r5, r1, 8
 
diff --git a/cpukit/score/cpu/microblaze/cpu_asm.S b/cpukit/score/cpu/microblaze/cpu_asm.S
index 246b397b9e..4dfc55ffbf 100644
--- a/cpukit/score/cpu/microblaze/cpu_asm.S
+++ b/cpukit/score/cpu/microblaze/cpu_asm.S
@@ -53,6 +53,8 @@ _ISR_Handler:
 	swi r12, r1, MICROBLAZE_INTERRUPT_FRAME_R12
 	swi r15, r1, MICROBLAZE_INTERRUPT_FRAME_R15
 	swi r18, r1, MICROBLAZE_INTERRUPT_FRAME_R18
+	mfs r3, rmsr
+	swi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_MSR
 
 	/* Disable dispatching */
 	lwi r3, r0, _Per_CPU_Information + 16
@@ -76,7 +78,7 @@ _ISR_Handler:
 switch_to_interrupt_stack:
 	add r4, r0, r1
 	lwi r1, r0, _Per_CPU_Information + 4
-	addik r1, r1, -52
+	addik r1, r1, -(CPU_INTERRUPT_FRAME_SIZE)
 	swi r4, r1, 0
 
 on_interrupt_stack:
@@ -118,6 +120,8 @@ after_stack_switch:
 quick_exit:
 	/* Simple return from nested interrupt */
 	/* Restore registers */
+	lwi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_MSR
+	mts  rmsr, r3
 	lwi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_R3
 	lwi  r4, r1, MICROBLAZE_INTERRUPT_FRAME_R4
 	lwi  r5, r1, MICROBLAZE_INTERRUPT_FRAME_R5
@@ -133,14 +137,14 @@ quick_exit:
 	lwi r18, r1, MICROBLAZE_INTERRUPT_FRAME_R18
 
 	/* Remove stack frame */
-	addik r1, r1, 52
+	addik r1, r1, CPU_INTERRUPT_FRAME_SIZE
 
 	rtid r14, 0
 	nop
 
 thread_dispatch:
 	/* Reserve stack */
-	addik r1, r1, -52
+	addik r1, r1, -(CPU_INTERRUPT_FRAME_SIZE)
 	/* Save scratch registers */
 	swi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_R3
 	swi  r4, r1, MICROBLAZE_INTERRUPT_FRAME_R4
@@ -155,11 +159,15 @@ thread_dispatch:
 	swi r14, r1, MICROBLAZE_INTERRUPT_FRAME_R14
 	swi r15, r1, MICROBLAZE_INTERRUPT_FRAME_R15
 	swi r18, r1, MICROBLAZE_INTERRUPT_FRAME_R18
+	mfs r3, rmsr
+	swi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_MSR
 
 	bralid r15, _Thread_Dispatch
 	nop
 
 	/* Restore scratch registers */
+	lwi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_MSR
+	mts  rmsr, r3
 	lwi  r3, r1, MICROBLAZE_INTERRUPT_FRAME_R3
 	lwi  r4, r1, MICROBLAZE_INTERRUPT_FRAME_R4
 	lwi  r5, r1, MICROBLAZE_INTERRUPT_FRAME_R5
@@ -174,6 +182,6 @@ thread_dispatch:
 	lwi r15, r1, MICROBLAZE_INTERRUPT_FRAME_R15
 	lwi r18, r1, MICROBLAZE_INTERRUPT_FRAME_R18
 	/* Free stack space */
-	addik r1, r1, 52
+	addik r1, r1, CPU_INTERRUPT_FRAME_SIZE
 
 	bri quick_exit
diff --git a/cpukit/score/cpu/microblaze/include/rtems/score/cpuimpl.h b/cpukit/score/cpu/microblaze/include/rtems/score/cpuimpl.h
index 3d0167dd40..0573759d52 100644
--- a/cpukit/score/cpu/microblaze/include/rtems/score/cpuimpl.h
+++ b/cpukit/score/cpu/microblaze/include/rtems/score/cpuimpl.h
@@ -49,7 +49,7 @@
  */
 
 #define CPU_PER_CPU_CONTROL_SIZE 0
-#define CPU_INTERRUPT_FRAME_SIZE 52
+#define CPU_INTERRUPT_FRAME_SIZE 56
 
 #define MICROBLAZE_INTERRUPT_FRAME_R3   0
 #define MICROBLAZE_INTERRUPT_FRAME_R4   4
@@ -64,6 +64,7 @@
 #define MICROBLAZE_INTERRUPT_FRAME_R14 40
 #define MICROBLAZE_INTERRUPT_FRAME_R15 44
 #define MICROBLAZE_INTERRUPT_FRAME_R18 48
+#define MICROBLAZE_INTERRUPT_FRAME_MSR 52
 
 #ifndef ASM
 
-- 
2.30.2