4 files changed, 4 insertions, 0 deletions
diff --git a/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.S b/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.S
index 3bb601541d..5ac3552403 100644
--- a/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.S
+++ b/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.S
@@ -347,6 +347,7 @@ ASM_PFX(ArmEnableVFP):
   orr     r0, r0, #0x00f00000
   # Write back CPACR (Coprocessor Access Control Register)
   mcr     p15, 0, r0, c1, c0, 2
+  isb
   # Set EN bit in FPEXC. The Advanced SIMD and VFP extensions are enabled and operate normally.
   mov     r0, #0x40000000
   mcr     p10,#0x7,r0,c8,c0,#0
diff --git a/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.asm b/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.asm
index 28a4564aca..8fedcdba97 100644
--- a/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.asm
+++ b/ArmPkg/Library/ArmLib/ArmV7/ArmV7Support.asm
@@ -341,6 +341,7 @@ ArmEnableVFP
   orr     r0, r0, #0x00f00000
   // Write back CPACR (Coprocessor Access Control Register)
   mcr     p15, 0, r0, c1, c0, 2
+  isb
   // Set EN bit in FPEXC. The Advanced SIMD and VFP extensions are enabled and operate normally.
   mov     r0, #0x40000000
   mcr     p10,#0x7,r0,c8,c0,#0
diff --git a/ArmPkg/Library/ArmLib/Common/ArmLibSupport.S b/ArmPkg/Library/ArmLib/Common/ArmLibSupport.S
index edd94d2995..d00a3623c5 100644
--- a/ArmPkg/Library/ArmLib/Common/ArmLibSupport.S
+++ b/ArmPkg/Library/ArmLib/Common/ArmLibSupport.S
@@ -88,6 +88,7 @@ ASM_PFX(CPSRRead):
 
 ASM_PFX(ArmWriteCPACR):
   mcr     p15, 0, r0, c1, c0, 2
+  isb
   bx      lr
 
 ASM_PFX(ArmWriteAuxCr):
diff --git a/ArmPkg/Library/ArmLib/Common/ArmLibSupport.asm b/ArmPkg/Library/ArmLib/Common/ArmLibSupport.asm
index 3f603873f3..b892603518 100644
--- a/ArmPkg/Library/ArmLib/Common/ArmLibSupport.asm
+++ b/ArmPkg/Library/ArmLib/Common/ArmLibSupport.asm
@@ -88,6 +88,7 @@ CPSRRead
 
 ArmWriteCPACR
   mcr     p15, 0, r0, c1, c0, 2
+  isb
   bx      lr
 
 ArmWriteAuxCr