[PATCH 1/2] cpukit/aarch64: Keep state across context switch

[Kinsey Moore]

If a task migrates to a newly turned-up CPU as the first task it
executes, no guarantees are made about whether interrupts are enabled
and it is possible for a task to change interrupt enable states during
the migration. This preserves interrupt state across context switches.
---
 cpukit/score/cpu/aarch64/cpu_asm.S                 | 4 ++++
 cpukit/score/cpu/aarch64/include/rtems/score/cpu.h | 7 ++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/cpukit/score/cpu/aarch64/cpu_asm.S 
b/cpukit/score/cpu/aarch64/cpu_asm.S
index 2379698336..4234b428aa 100644
--- a/cpukit/score/cpu/aarch64/cpu_asm.S
+++ b/cpukit/score/cpu/aarch64/cpu_asm.S
@@ -83,6 +83,8 @@ DEFINE_FUNCTION_AARCH64(_CPU_Context_switch)
        stp fp,  lr,  [x0, #0x50]
        mov x4,  sp
        str x4,  [x0, #0x60]
+       mrs x5,  daif
+       str x5,  [x0, #0x78]
 
 #ifdef AARCH64_MULTILIB_VFP
        add     x5, x0, #AARCH64_CONTEXT_CONTROL_D8_OFFSET
@@ -151,6 +153,8 @@ DEFINE_FUNCTION_AARCH64(_CPU_Context_switch)
        ldp fp,  lr,  [x1, #0x50]
        ldr x4,  [x1, #0x60]
        mov sp,  x4
+       ldr x5,  [x1, #0x78]
+       msr daif, x5
        ret
 
 /*
diff --git a/cpukit/score/cpu/aarch64/include/rtems/score/cpu.h 
b/cpukit/score/cpu/aarch64/include/rtems/score/cpu.h
index e1d9f0a5c2..2f252bf2f4 100644
--- a/cpukit/score/cpu/aarch64/include/rtems/score/cpu.h
+++ b/cpukit/score/cpu/aarch64/include/rtems/score/cpu.h
@@ -127,16 +127,16 @@
 #define AARCH64_CONTEXT_CONTROL_THREAD_ID_OFFSET 0x70
 
 #ifdef AARCH64_MULTILIB_VFP
-  #define AARCH64_CONTEXT_CONTROL_D8_OFFSET 0x78
+  #define AARCH64_CONTEXT_CONTROL_D8_OFFSET 0x80
 #endif
 
 #define AARCH64_CONTEXT_CONTROL_ISR_DISPATCH_DISABLE 0x68
 
 #ifdef RTEMS_SMP
   #if defined(AARCH64_MULTILIB_VFP)
-    #define AARCH64_CONTEXT_CONTROL_IS_EXECUTING_OFFSET 0xb8
+    #define AARCH64_CONTEXT_CONTROL_IS_EXECUTING_OFFSET 0xc0
   #else
-    #define AARCH64_CONTEXT_CONTROL_IS_EXECUTING_OFFSET 0x78
+    #define AARCH64_CONTEXT_CONTROL_IS_EXECUTING_OFFSET 0x80
   #endif
 #endif
 
@@ -174,6 +174,7 @@ typedef struct {
   uint64_t register_sp;
   uint64_t isr_dispatch_disable;
   uint64_t thread_id;
+  uint64_t daif;
 #ifdef AARCH64_MULTILIB_VFP
   uint64_t register_d8;
   uint64_t register_d9;
-- 
2.30.2

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