From 355f8dd95cddcf784eb60bfea0a8d6ebf130fdf3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E4=B8=96=E4=BA=89?= <zhangshizheng@rt-thread.com>
Date: Fri, 20 Nov 2020 08:49:51 +0800
Subject: [PATCH] =?UTF-8?q?[libcpu][update]=E9=87=8D=E5=90=AF=E4=B8=8E?=
 =?UTF-8?q?=E5=85=B3=E6=9C=BA=E5=87=BD=E6=95=B0=EF=BC=9Art=5Fhw=5Fcpu=5Fsh?=
 =?UTF-8?q?utdown=E3=80=81rt=5Fhw=5Fcpu=5Freset=EF=BC=8C=E8=A1=A5=E5=85=85?=
 =?UTF-8?q?WEAK=E5=B1=9E=E6=80=A7?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 libcpu/aarch64/common/cpu.c         | 2 +-
 libcpu/arc/em/cpuport.c             | 2 +-
 libcpu/arm/AT91SAM7S/cpu.c          | 4 ++--
 libcpu/arm/AT91SAM7X/cpu.c          | 4 ++--
 libcpu/arm/am335x/cpu.c             | 2 +-
 libcpu/arm/arm926/cpuport.c         | 4 ++--
 libcpu/arm/armv6/cpuport.c          | 4 ++--
 libcpu/arm/cortex-a/cpu.c           | 2 +-
 libcpu/arm/cortex-m3/cpuport.c      | 2 +-
 libcpu/arm/cortex-m33/cpuport.c     | 2 +-
 libcpu/arm/cortex-m4/cpuport.c      | 2 +-
 libcpu/arm/cortex-m7/cpuport.c      | 2 +-
 libcpu/arm/cortex-r4/cpu.c          | 4 ++--
 libcpu/arm/dm36x/cpuport.c          | 4 ++--
 libcpu/arm/lpc214x/cpuport.c        | 4 ++--
 libcpu/arm/lpc24xx/cpu.c            | 4 ++--
 libcpu/arm/realview-a8-vmm/cpu.c    | 2 +-
 libcpu/arm/s3c24x0/cpu.c            | 4 ++--
 libcpu/arm/s3c44b0/cpu.c            | 4 ++--
 libcpu/arm/sep4020/cpu.c            | 4 ++--
 libcpu/arm/zynq7000/cpu.c           | 4 ++--
 libcpu/avr32/uc3/cpu.c              | 2 +-
 libcpu/mips/gs232/cpuport.c         | 4 ++--
 libcpu/risc-v/common/cpuport.c      | 2 +-
 libcpu/risc-v/nuclei/cpuport.c      | 2 +-
 libcpu/risc-v/t-head/e906/cpuport.c | 2 +-
 libcpu/rx/cpuport.c                 | 2 +-
 libcpu/ti-dsp/c28x/cpuport.c        | 2 +-
 libcpu/unicore32/sep6200/cpu.c      | 4 ++--
 libcpu/xilinx/microblaze/cpu.c      | 4 ++--
 30 files changed, 45 insertions(+), 45 deletions(-)

diff --git a/libcpu/aarch64/common/cpu.c b/libcpu/aarch64/common/cpu.c
index 962a53a071..84d3df2e8a 100644
--- a/libcpu/aarch64/common/cpu.c
+++ b/libcpu/aarch64/common/cpu.c
@@ -76,7 +76,7 @@ void rt_hw_spin_unlock(rt_hw_spinlock_t *lock)
 /*@{*/
 
 /** shutdown CPU */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/arc/em/cpuport.c b/libcpu/arc/em/cpuport.c
index 34f538881f..1a2593644a 100644
--- a/libcpu/arc/em/cpuport.c
+++ b/libcpu/arc/em/cpuport.c
@@ -32,7 +32,7 @@ struct init_stack_frame {
 /**
  * shutdown CPU
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
 
 }
diff --git a/libcpu/arm/AT91SAM7S/cpu.c b/libcpu/arm/AT91SAM7S/cpu.c
index 8d28063eb1..b24ab5644b 100644
--- a/libcpu/arm/AT91SAM7S/cpu.c
+++ b/libcpu/arm/AT91SAM7S/cpu.c
@@ -20,7 +20,7 @@
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 }
 
@@ -28,7 +28,7 @@ void rt_hw_cpu_reset()
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/AT91SAM7X/cpu.c b/libcpu/arm/AT91SAM7X/cpu.c
index 484c19d10a..046f7e8ced 100644
--- a/libcpu/arm/AT91SAM7X/cpu.c
+++ b/libcpu/arm/AT91SAM7X/cpu.c
@@ -20,7 +20,7 @@
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 }
 
@@ -28,7 +28,7 @@ void rt_hw_cpu_reset()
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/am335x/cpu.c b/libcpu/arm/am335x/cpu.c
index cae865fe50..469276466b 100644
--- a/libcpu/arm/am335x/cpu.c
+++ b/libcpu/arm/am335x/cpu.c
@@ -149,7 +149,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/arm926/cpuport.c b/libcpu/arm/arm926/cpuport.c
index 035e97d543..dc93f42ed6 100644
--- a/libcpu/arm/arm926/cpuport.c
+++ b/libcpu/arm/arm926/cpuport.c
@@ -146,7 +146,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 
     rt_kprintf("Restarting system...\n");
@@ -161,7 +161,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/armv6/cpuport.c b/libcpu/arm/armv6/cpuport.c
index c8e9201722..f886e7e164 100644
--- a/libcpu/arm/armv6/cpuport.c
+++ b/libcpu/arm/armv6/cpuport.c
@@ -147,7 +147,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 	
 	rt_kprintf("Restarting system...\n");
@@ -162,7 +162,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/cortex-a/cpu.c b/libcpu/arm/cortex-a/cpu.c
index 7c6bf58a4b..6775b781bc 100644
--- a/libcpu/arm/cortex-a/cpu.c
+++ b/libcpu/arm/cortex-a/cpu.c
@@ -74,7 +74,7 @@ void rt_hw_spin_unlock(rt_hw_spinlock_t *lock)
 /*@{*/
 
 /** shutdown CPU */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/cortex-m3/cpuport.c b/libcpu/arm/cortex-m3/cpuport.c
index d58782e2c5..b6c4c9743c 100644
--- a/libcpu/arm/cortex-m3/cpuport.c
+++ b/libcpu/arm/cortex-m3/cpuport.c
@@ -344,7 +344,7 @@ void rt_hw_hard_fault_exception(struct exception_info * exception_info)
 /**
  * shutdown CPU
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/cortex-m33/cpuport.c b/libcpu/arm/cortex-m33/cpuport.c
index a589ba3462..42b5798507 100644
--- a/libcpu/arm/cortex-m33/cpuport.c
+++ b/libcpu/arm/cortex-m33/cpuport.c
@@ -431,7 +431,7 @@ void rt_hw_hard_fault_exception(struct exception_info *exception_info)
 /**
  * shutdown CPU
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/cortex-m4/cpuport.c b/libcpu/arm/cortex-m4/cpuport.c
index dc8a9aab59..2e47832259 100644
--- a/libcpu/arm/cortex-m4/cpuport.c
+++ b/libcpu/arm/cortex-m4/cpuport.c
@@ -428,7 +428,7 @@ void rt_hw_hard_fault_exception(struct exception_info *exception_info)
 /**
  * shutdown CPU
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/cortex-m7/cpuport.c b/libcpu/arm/cortex-m7/cpuport.c
index e701a52307..aeb9f14ac5 100644
--- a/libcpu/arm/cortex-m7/cpuport.c
+++ b/libcpu/arm/cortex-m7/cpuport.c
@@ -428,7 +428,7 @@ void rt_hw_hard_fault_exception(struct exception_info *exception_info)
 /**
  * shutdown CPU
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/cortex-r4/cpu.c b/libcpu/arm/cortex-r4/cpu.c
index d2e8130e7c..23c16e383c 100644
--- a/libcpu/arm/cortex-r4/cpu.c
+++ b/libcpu/arm/cortex-r4/cpu.c
@@ -20,7 +20,7 @@
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 }
 
@@ -28,7 +28,7 @@ void rt_hw_cpu_reset()
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/dm36x/cpuport.c b/libcpu/arm/dm36x/cpuport.c
index f6e8a20056..99edb96260 100644
--- a/libcpu/arm/dm36x/cpuport.c
+++ b/libcpu/arm/dm36x/cpuport.c
@@ -145,7 +145,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 	
 	rt_kprintf("Restarting system...\n");
@@ -160,7 +160,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/lpc214x/cpuport.c b/libcpu/arm/lpc214x/cpuport.c
index 2543a5e0a9..54e7e9b0c8 100644
--- a/libcpu/arm/lpc214x/cpuport.c
+++ b/libcpu/arm/lpc214x/cpuport.c
@@ -163,7 +163,7 @@ rt_isr_handler_t rt_hw_interrupt_install(int vector, rt_isr_handler_t handler,
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset(void)
+RT_WEAK void rt_hw_cpu_reset(void)
 {
 }
 
@@ -171,7 +171,7 @@ void rt_hw_cpu_reset(void)
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/lpc24xx/cpu.c b/libcpu/arm/lpc24xx/cpu.c
index f3a61e16a3..0453722d1d 100644
--- a/libcpu/arm/lpc24xx/cpu.c
+++ b/libcpu/arm/lpc24xx/cpu.c
@@ -20,7 +20,7 @@
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 }
 
@@ -28,7 +28,7 @@ void rt_hw_cpu_reset()
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/realview-a8-vmm/cpu.c b/libcpu/arm/realview-a8-vmm/cpu.c
index 2d78715011..dbdb4ac515 100644
--- a/libcpu/arm/realview-a8-vmm/cpu.c
+++ b/libcpu/arm/realview-a8-vmm/cpu.c
@@ -18,7 +18,7 @@
 /*@{*/
 
 /** shutdown CPU */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/s3c24x0/cpu.c b/libcpu/arm/s3c24x0/cpu.c
index 4d3bf3c1ab..2adf526a5c 100644
--- a/libcpu/arm/s3c24x0/cpu.c
+++ b/libcpu/arm/s3c24x0/cpu.c
@@ -148,7 +148,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 	/* Disable all interrupt except the WDT */
 	INTMSK = (~((rt_uint32_t)1 << INTWDT));
@@ -171,7 +171,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/s3c44b0/cpu.c b/libcpu/arm/s3c44b0/cpu.c
index 03ebefba18..9d60b09688 100644
--- a/libcpu/arm/s3c44b0/cpu.c
+++ b/libcpu/arm/s3c44b0/cpu.c
@@ -100,7 +100,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 }
 
@@ -108,7 +108,7 @@ void rt_hw_cpu_reset()
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/arm/sep4020/cpu.c b/libcpu/arm/sep4020/cpu.c
index ee4eab626b..92ba2cf86a 100644
--- a/libcpu/arm/sep4020/cpu.c
+++ b/libcpu/arm/sep4020/cpu.c
@@ -152,7 +152,7 @@ rt_base_t rt_hw_cpu_dcache_status()
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 
 	/* enable watchdog */
@@ -173,7 +173,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t UNUSED level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/arm/zynq7000/cpu.c b/libcpu/arm/zynq7000/cpu.c
index 5f3a3e7b02..f6b7f5d852 100644
--- a/libcpu/arm/zynq7000/cpu.c
+++ b/libcpu/arm/zynq7000/cpu.c
@@ -16,7 +16,7 @@
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
     while (1);  /* loop forever and wait for reset to happen */
 
@@ -27,7 +27,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/avr32/uc3/cpu.c b/libcpu/avr32/uc3/cpu.c
index b77e78dc5b..fdd8a4d56c 100644
--- a/libcpu/avr32/uc3/cpu.c
+++ b/libcpu/avr32/uc3/cpu.c
@@ -23,7 +23,7 @@
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 	/*NOTREACHED*/
 }
diff --git a/libcpu/mips/gs232/cpuport.c b/libcpu/mips/gs232/cpuport.c
index 1b13719449..e3c078241f 100644
--- a/libcpu/mips/gs232/cpuport.c
+++ b/libcpu/mips/gs232/cpuport.c
@@ -23,7 +23,7 @@
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset(void)
+RT_WEAK void rt_hw_cpu_reset(void)
 {
     /* open the watch-dog */
     WDT_EN = 0x01; 		/* watch dog enable */
@@ -38,7 +38,7 @@ void rt_hw_cpu_reset(void)
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/risc-v/common/cpuport.c b/libcpu/risc-v/common/cpuport.c
index a44dc40f79..5da3e85645 100644
--- a/libcpu/risc-v/common/cpuport.c
+++ b/libcpu/risc-v/common/cpuport.c
@@ -116,7 +116,7 @@ void rt_hw_context_switch_interrupt(rt_ubase_t from, rt_ubase_t to)
 #endif /* end of RT_USING_SMP */
 
 /** shutdown CPU */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/risc-v/nuclei/cpuport.c b/libcpu/risc-v/nuclei/cpuport.c
index e456438f70..717e9bb1c7 100644
--- a/libcpu/risc-v/nuclei/cpuport.c
+++ b/libcpu/risc-v/nuclei/cpuport.c
@@ -152,7 +152,7 @@ void rt_hw_context_switch(rt_ubase_t from, rt_ubase_t to)
  * @brief shutdown CPU
  * 
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/risc-v/t-head/e906/cpuport.c b/libcpu/risc-v/t-head/e906/cpuport.c
index 5597aa237a..998bfdc340 100644
--- a/libcpu/risc-v/t-head/e906/cpuport.c
+++ b/libcpu/risc-v/t-head/e906/cpuport.c
@@ -157,7 +157,7 @@ void rt_hw_interrupt_enable(rt_base_t level)
 }
 
 /** shutdown CPU */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
     rt_uint32_t level;
     rt_kprintf("shutdown...\n");
diff --git a/libcpu/rx/cpuport.c b/libcpu/rx/cpuport.c
index 681c0e8e6e..a01f598e99 100644
--- a/libcpu/rx/cpuport.c
+++ b/libcpu/rx/cpuport.c
@@ -182,7 +182,7 @@ void rt_hw_context_switch_interrupt(rt_uint32_t from, rt_uint32_t to)
  * 
  * @author LXZ (2014/11/8)
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/ti-dsp/c28x/cpuport.c b/libcpu/ti-dsp/c28x/cpuport.c
index 3f88606c65..0c7dce2a4e 100644
--- a/libcpu/ti-dsp/c28x/cpuport.c
+++ b/libcpu/ti-dsp/c28x/cpuport.c
@@ -121,7 +121,7 @@ int __rt_ffs(int value)
 /**
  * shutdown CPU
  */
-void rt_hw_cpu_shutdown(void)
+RT_WEAK void rt_hw_cpu_shutdown(void)
 {
     rt_kprintf("shutdown...\n");
 
diff --git a/libcpu/unicore32/sep6200/cpu.c b/libcpu/unicore32/sep6200/cpu.c
index ebea8750e1..9452b4e59d 100644
--- a/libcpu/unicore32/sep6200/cpu.c
+++ b/libcpu/unicore32/sep6200/cpu.c
@@ -259,7 +259,7 @@ static void sep6200_poweroff(void)
  * reset cpu by dog's time-out
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 
 	rt_kprintf("Soft reset, Restarting system...\n");
@@ -274,7 +274,7 @@ void rt_hw_cpu_reset()
  *  shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_uint32_t level;
 	rt_kprintf("shutdown...\n");
diff --git a/libcpu/xilinx/microblaze/cpu.c b/libcpu/xilinx/microblaze/cpu.c
index 50a0e34dcd..d37dcda350 100755
--- a/libcpu/xilinx/microblaze/cpu.c
+++ b/libcpu/xilinx/microblaze/cpu.c
@@ -18,7 +18,7 @@
  * this function will reset CPU
  *
  */
-void rt_hw_cpu_reset()
+RT_WEAK void rt_hw_cpu_reset()
 {
 }
 
@@ -26,7 +26,7 @@ void rt_hw_cpu_reset()
  * this function will shutdown CPU
  *
  */
-void rt_hw_cpu_shutdown()
+RT_WEAK void rt_hw_cpu_shutdown()
 {
 	rt_kprintf("shutdown...\n");