arm64: optimise for arm64_switchcontext

       We can save execution time by
       inline arm64_fullcontextrestore and arm64_switchcontext

test:
We can use qemu for testing.

compiling
make distclean -j20; ./tools/configure.sh -l qemu-armv8a:nsh_smp ;make -j20
running
qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic -machine virt,virtualization=on,gic-version=3 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx

Signed-off-by: hujun5 <hujun5@xiaomi.com>

arch/arm64/src/common/Make.defs

@@ -45,7 +45,7 @@ endif
 CMN_CSRCS =  arm64_initialize.c arm64_initialstate.c arm64_boot.c
 CMN_CSRCS += arm64_nputs.c arm64_idle.c arm64_copystate.c arm64_createstack.c
 CMN_CSRCS += arm64_releasestack.c arm64_stackframe.c arm64_usestack.c
-CMN_CSRCS += arm64_task_sched.c arm64_exit.c arm64_fork.c arm64_switchcontext.c
+CMN_CSRCS += arm64_exit.c arm64_fork.c arm64_switchcontext.c
 CMN_CSRCS += arm64_schedulesigaction.c arm64_sigdeliver.c
 CMN_CSRCS += arm64_getintstack.c arm64_registerdump.c
 CMN_CSRCS += arm64_perf.c arm64_tcbinfo.c

arch/arm64/src/common/arm64_internal.h

@@ -32,6 +32,7 @@
 #  include <nuttx/arch.h>
 #  include <sys/types.h>
 #  include <stdint.h>
+#  include <syscall.h>
 #endif
 
 #include "arm64_arch.h"
@@ -116,6 +117,18 @@
 #  define SMP_STACK_WORDS   (SMP_STACK_SIZE >> 2)
 #endif
 
+/* Context switching */
+
+#define arm64_fullcontextrestore(restoreregs) \
+  do \
+    { \
+      sys_call1(SYS_restore_context, (uintptr_t)restoreregs); \
+    } \
+  while (1)
+
+#define arm64_switchcontext(saveregs, restoreregs) \
+  sys_call2(SYS_switch_context, (uintptr_t)saveregs, (uintptr_t)restoreregs)
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -267,11 +280,6 @@ int arm64_psci_init(const char *method);
 void __start(void);
 void arm64_secondary_start(void);
 
-/* Context switching */
-
-void arm64_fullcontextrestore(uint64_t *restoreregs) noreturn_function;
-void arm64_switchcontext(uint64_t **saveregs, uint64_t *restoreregs);
-
 /* Signal handling **********************************************************/
 
 void arm64_sigdeliver(void);