Remove clrex instruction from Cortex-M ports again as it is implicit in interrupt entry.

FreeRTOS/Source/portable/CCS/ARM_CM4F/portasm.asm

@@ -123,9 +123,6 @@ xPortPendSVHandler: .asmfunc
 	;/* Save the new top of stack into the first member of the TCB. */
 	str r0, [r2]
 
-	;/* Ensure thread safety of atomic operations. */
-	clrex
-
 	stmdb sp!, {r3}
 	ldr r0, ulMaxSyscallInterruptPriorityConst
 	ldr r1, [r0]

FreeRTOS/Source/portable/GCC/ARM_CM3/port.c

@@ -410,7 +410,6 @@ void xPortPendSVHandler( void )
 	"										\n"
 	"	stmdb r0!, {r4-r11}					\n" /* Save the remaining registers. */
 	"	str r0, [r2]						\n" /* Save the new top of stack into the first member of the TCB. */
-	"	clrex								\n" /* Ensure thread safety of atomic operations. */
 	"										\n"
 	"	stmdb sp!, {r3, r14}				\n"
 	"	mov r0, %0							\n"

FreeRTOS/Source/portable/GCC/ARM_CM3_MPU/port.c

@@ -450,7 +450,6 @@ void xPortPendSVHandler( void )
 		"	mrs r1, control						\n"
 		"	stmdb r0!, {r1, r4-r11}				\n" /* Save the remaining registers. */
 		"	str r0, [r2]						\n" /* Save the new top of stack into the first member of the TCB. */
-		"	clrex								\n" /* Ensure thread safety of atomic operations. */
 		"										\n"
 		"	stmdb sp!, {r3, r14}				\n"
 		"	mov r0, %0							\n"

FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c

@@ -450,7 +450,6 @@ void xPortPendSVHandler( void )
 	"										\n"
 	"	stmdb r0!, {r4-r11, r14}			\n" /* Save the core registers. */
 	"	str r0, [r2]						\n" /* Save the new top of stack into the first member of the TCB. */
-	"	clrex								\n" /* Ensure thread safety of atomic operations. */
 	"										\n"
 	"	stmdb sp!, {r3}						\n"
 	"	mov r0, %0 							\n"

FreeRTOS/Source/portable/GCC/ARM_CM4_MPU/port.c

@@ -477,7 +477,6 @@ void xPortPendSVHandler( void )
 		"	mrs r1, control						\n"
 		"	stmdb r0!, {r1, r4-r11, r14}		\n" /* Save the remaining registers. */
 		"	str r0, [r2]						\n" /* Save the new top of stack into the first member of the TCB. */
-		"	clrex								\n" /* Ensure thread safety of atomic operations. */
 		"										\n"
 		"	stmdb sp!, {r3}						\n"
 		"	mov r0, %0							\n"

FreeRTOS/Source/portable/GCC/ARM_CM7/r0p1/port.c

@@ -438,7 +438,6 @@ void xPortPendSVHandler( void )
 	"										\n"
 	"	stmdb r0!, {r4-r11, r14}			\n" /* Save the core registers. */
 	"	str r0, [r2]						\n" /* Save the new top of stack into the first member of the TCB. */
-	"	clrex								\n" /* Ensure thread safety of atomic operations. */
 	"										\n"
 	"	stmdb sp!, {r3}						\n"
 	"	mov r0, %0 							\n"

FreeRTOS/Source/portable/IAR/ARM_CM3/portasm.s

@@ -91,7 +91,6 @@ xPortPendSVHandler:
 
 	stmdb r0!, {r4-r11}				/* Save the remaining registers. */
 	str r0, [r2]					/* Save the new top of stack into the first member of the TCB. */
-	clrex							/* Ensure thread safety of atomic operations. */
 
 	stmdb sp!, {r3, r14}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

FreeRTOS/Source/portable/IAR/ARM_CM4F/portasm.s

@@ -101,9 +101,6 @@ xPortPendSVHandler:
 	/* Save the new top of stack into the first member of the TCB. */
 	str r0, [r2]
 
-	/* Ensure thread safety of atomic operations. */
-	clrex
-
 	stmdb sp!, {r3}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
 	msr basepri, r0

FreeRTOS/Source/portable/IAR/ARM_CM7/r0p1/portasm.s

@@ -101,9 +101,6 @@ xPortPendSVHandler:
 	/* Save the new top of stack into the first member of the TCB. */
 	str r0, [r2]
 
-	/* Ensure thread safety of atomic operations. */
-	clrex
-
 	stmdb sp!, {r3}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
 	cpsid i

FreeRTOS/Source/portable/MikroC/ARM_CM4F/port.c

@@ -458,8 +458,6 @@ void xPortPendSVHandler( void ) iv IVT_INT_PendSV ics ICS_OFF
 
 	str r0, [r2]			 /* Save the new top of stack into the first member of the TCB. */
 
-	clrex					/* Ensure thread safety of atomic operations. */
-
 	stmdb sp!, (r3)
 	ldr r0, =_ucMaxSyscallInterruptPriority
 	ldr r1, [r0]

FreeRTOS/Source/portable/RVDS/ARM_CM3/port.c

@@ -407,7 +407,6 @@ __asm void xPortPendSVHandler( void )
 
 	stmdb r0!, {r4-r11}			/* Save the remaining registers. */
 	str r0, [r2]				/* Save the new top of stack into the first member of the TCB. */
-	clrex						/* Ensure thread safety of atomic operations. */
 
 	stmdb sp!, {r3, r14}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

FreeRTOS/Source/portable/RVDS/ARM_CM4F/port.c

@@ -479,9 +479,6 @@ __asm void xPortPendSVHandler( void )
 	/* Save the new top of stack into the first member of the TCB. */
 	str r0, [r2]
 
-	/* Ensure thread safety of atomic operations. */
-	clrex
-
 	stmdb sp!, {r3}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
 	msr basepri, r0

FreeRTOS/Source/portable/RVDS/ARM_CM4_MPU/port.c

@@ -492,7 +492,6 @@ __asm void xPortPendSVHandler( void )
 	mrs r1, control
 	stmdb r0!, {r1, r4-r11, r14}	/* Save the remaining registers. */
 	str r0, [r2]					/* Save the new top of stack into the first member of the TCB. */
-	clrex							/* Ensure thread safety of atomic operations. */
 
 	stmdb sp!, {r3}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY

FreeRTOS/Source/portable/RVDS/ARM_CM7/r0p1/port.c

@@ -463,9 +463,6 @@ __asm void xPortPendSVHandler( void )
 	/* Save the new top of stack into the first member of the TCB. */
 	str r0, [r2]
 
-	/* Ensure thread safety of atomic operations. */
-	clrex
-
 	stmdb sp!, {r3}
 	mov r0, #configMAX_SYSCALL_INTERRUPT_PRIORITY
 	cpsid i