fix:fix wch startup risks.

1: If IAP has set mstatus to other value, using csrs will not change old value of mstatus in IAP. It should using csrw instead.
2: Reduce the flash size of undefined irq functions.

bsp/wch/risc-v/Libraries/CH32V10x_StdPeriph_Driver/CMSIS/WCH/CH32V10x/Source/GCC/startup_ch32v10x.S

@@ -174,7 +174,7 @@ handle_reset:
 2:
 	/* disable interrupt */
   	li t0, 0x1800
-  	csrs mstatus, t0
+  	csrw mstatus, t0
 	la t0, _vector_base
   	ori t0, t0, 1
 	csrw mtvec, t0

bsp/wch/risc-v/Libraries/ch32v20x_libraries/bmsis/source/startup_ch32v20x_D8W.S

@@ -168,67 +168,69 @@ _vector_base:
     .weak   OSC32KCal_IRQHandler       /* OSC32 KCal */
     .weak   OSCWakeUp_IRQHandler       /* OSC Wake Up */
 
-NMI_Handler:  1:  j 1b
-HardFault_Handler:  1:  j 1b
-Ecall_M_Mode_Handler:  1:  j 1b
-Ecall_U_Mode_Handler:  1:  j 1b
-Break_Point_Handler:  1:  j 1b
-SysTick_Handler:  1:  j 1b
-SW_handler:  1:  j 1b
-WWDG_IRQHandler:  1:  j 1b
-PVD_IRQHandler:  1:  j 1b
-TAMPER_IRQHandler:  1:  j 1b
-RTC_IRQHandler:  1:  j 1b
-FLASH_IRQHandler:  1:  j 1b
-RCC_IRQHandler:  1:  j 1b
-EXTI0_IRQHandler:  1:  j 1b
-EXTI1_IRQHandler:  1:  j 1b
-EXTI2_IRQHandler:  1:  j 1b
-EXTI3_IRQHandler:  1:  j 1b
-EXTI4_IRQHandler:  1:  j 1b
-DMA1_Channel1_IRQHandler:  1:  j 1b
-DMA1_Channel2_IRQHandler:  1:  j 1b
-DMA1_Channel3_IRQHandler:  1:  j 1b
-DMA1_Channel4_IRQHandler:  1:  j 1b
-DMA1_Channel5_IRQHandler:  1:  j 1b
-DMA1_Channel6_IRQHandler:  1:  j 1b
-DMA1_Channel7_IRQHandler:  1:  j 1b
-ADC1_2_IRQHandler:  1:  j 1b
-USB_HP_CAN1_TX_IRQHandler:  1:  j 1b
-USB_LP_CAN1_RX0_IRQHandler:  1:  j 1b
-CAN1_RX1_IRQHandler:  1:  j 1b
-CAN1_SCE_IRQHandler:  1:  j 1b
-EXTI9_5_IRQHandler:  1:  j 1b
-TIM1_BRK_IRQHandler:  1:  j 1b
-TIM1_UP_IRQHandler:  1:  j 1b
-TIM1_TRG_COM_IRQHandler:  1:  j 1b
-TIM1_CC_IRQHandler:  1:  j 1b
-TIM2_IRQHandler:  1:  j 1b
-TIM3_IRQHandler:  1:  j 1b
-TIM4_IRQHandler:  1:  j 1b
-I2C1_EV_IRQHandler:  1:  j 1b
-I2C1_ER_IRQHandler:  1:  j 1b
-I2C2_EV_IRQHandler:  1:  j 1b
-I2C2_ER_IRQHandler:  1:  j 1b
-SPI1_IRQHandler:  1:  j 1b
-SPI2_IRQHandler:  1:  j 1b
-USART1_IRQHandler:  1:  j 1b
-USART2_IRQHandler:  1:  j 1b
-USART3_IRQHandler:  1:  j 1b
-EXTI15_10_IRQHandler:  1:  j 1b
-RTCAlarm_IRQHandler:  1:  j 1b
-USBWakeUp_IRQHandler:  1:  j 1b
-USBHD_IRQHandler:  1:  j 1b
-USBHDWakeUp_IRQHandler:  1:  j 1b
-ETH_IRQHandler:  1:  j 1b
-ETHWakeUp_IRQHandler:  1:  j 1b
-BB_IRQHandler:  1:  j 1b
-LLE_IRQHandler:  1:  j 1b
-TIM5_IRQHandler:  1:  j 1b
-UART4_IRQHandler:  1:  j 1b
-DMA1_Channel8_IRQHandler:  1:  j 1b
-OSC32KCal_IRQHandler:  1:  j 1b
-OSCWakeUp_IRQHandler:  1:  j 1b
+NMI_Handler:
+HardFault_Handler:
+Ecall_M_Mode_Handler:
+Ecall_U_Mode_Handler:
+Break_Point_Handler:
+SysTick_Handler:
+SW_handler:
+WWDG_IRQHandler:
+PVD_IRQHandler:
+TAMPER_IRQHandler:
+RTC_IRQHandler:
+FLASH_IRQHandler:
+RCC_IRQHandler:
+EXTI0_IRQHandler:
+EXTI1_IRQHandler:
+EXTI2_IRQHandler:
+EXTI3_IRQHandler:
+EXTI4_IRQHandler:
+DMA1_Channel1_IRQHandler:
+DMA1_Channel2_IRQHandler:
+DMA1_Channel3_IRQHandler:
+DMA1_Channel4_IRQHandler:
+DMA1_Channel5_IRQHandler:
+DMA1_Channel6_IRQHandler:
+DMA1_Channel7_IRQHandler:
+ADC1_2_IRQHandler:
+USB_HP_CAN1_TX_IRQHandler:
+USB_LP_CAN1_RX0_IRQHandler:
+CAN1_RX1_IRQHandler:
+CAN1_SCE_IRQHandler:
+EXTI9_5_IRQHandler:
+TIM1_BRK_IRQHandler:
+TIM1_UP_IRQHandler:
+TIM1_TRG_COM_IRQHandler:
+TIM1_CC_IRQHandler:
+TIM2_IRQHandler:
+TIM3_IRQHandler:
+TIM4_IRQHandler:
+I2C1_EV_IRQHandler:
+I2C1_ER_IRQHandler:
+I2C2_EV_IRQHandler:
+I2C2_ER_IRQHandler:
+SPI1_IRQHandler:
+SPI2_IRQHandler:
+USART1_IRQHandler:
+USART2_IRQHandler:
+USART3_IRQHandler:
+EXTI15_10_IRQHandler:
+RTCAlarm_IRQHandler:
+USBWakeUp_IRQHandler:
+USBHD_IRQHandler:
+USBHDWakeUp_IRQHandler:
+ETH_IRQHandler:
+ETHWakeUp_IRQHandler:
+BB_IRQHandler:
+LLE_IRQHandler:
+TIM5_IRQHandler:
+UART4_IRQHandler:
+DMA1_Channel8_IRQHandler:
+OSC32KCal_IRQHandler:
+OSCWakeUp_IRQHandler:
+1:
+    j 1b
 
 	.section	.text.handle_reset,"ax",@progbits
 	.weak	handle_reset
@@ -271,7 +273,7 @@ handle_reset:
 
     /* Enable interrupt */
    	li t0, 0x1800           
-   	csrs mstatus, t0
+   	csrw mstatus, t0
 
  	la t0, _vector_base
     ori t0, t0, 3           

bsp/wch/risc-v/Libraries/ch32v30x_libraries/bmsis/source/startup_ch32v30x.S

@@ -233,101 +233,103 @@ _vector_base:
     .weak   DMA2_Channel10_IRQHandler  /* DMA2 Channel 10 */
     .weak   DMA2_Channel11_IRQHandler  /* DMA2 Channel 11 */
 
-NMI_Handler:  1:  j 1b
-HardFault_Handler:  1:  j 1b
-Ecall_M_Mode_Handler:  1:  j 1b
-Ecall_U_Mode_Handler:  1:  j 1b
-Break_Point_Handler:  1:  j 1b
-SysTick_Handler:  1:  j 1b
-SW_handler:  1:  j 1b
-WWDG_IRQHandler:  1:  j 1b
-PVD_IRQHandler:  1:  j 1b
-TAMPER_IRQHandler:  1:  j 1b
-RTC_IRQHandler:  1:  j 1b
-FLASH_IRQHandler:  1:  j 1b
-RCC_IRQHandler:  1:  j 1b
-EXTI0_IRQHandler:  1:  j 1b
-EXTI1_IRQHandler:  1:  j 1b
-EXTI2_IRQHandler:  1:  j 1b
-EXTI3_IRQHandler:  1:  j 1b
-EXTI4_IRQHandler:  1:  j 1b
-DMA1_Channel1_IRQHandler:  1:  j 1b
-DMA1_Channel2_IRQHandler:  1:  j 1b
-DMA1_Channel3_IRQHandler:  1:  j 1b
-DMA1_Channel4_IRQHandler:  1:  j 1b
-DMA1_Channel5_IRQHandler:  1:  j 1b
-DMA1_Channel6_IRQHandler:  1:  j 1b
-DMA1_Channel7_IRQHandler:  1:  j 1b
-ADC1_2_IRQHandler:  1:  j 1b
-USB_HP_CAN1_TX_IRQHandler:  1:  j 1b
-USB_LP_CAN1_RX0_IRQHandler:  1:  j 1b
-CAN1_RX1_IRQHandler:  1:  j 1b
-CAN1_SCE_IRQHandler:  1:  j 1b
-EXTI9_5_IRQHandler:  1:  j 1b
-TIM1_BRK_IRQHandler:  1:  j 1b
-TIM1_UP_IRQHandler:  1:  j 1b
-TIM1_TRG_COM_IRQHandler:  1:  j 1b
-TIM1_CC_IRQHandler:  1:  j 1b
-TIM2_IRQHandler:  1:  j 1b
-TIM3_IRQHandler:  1:  j 1b
-TIM4_IRQHandler:  1:  j 1b
-I2C1_EV_IRQHandler:  1:  j 1b
-I2C1_ER_IRQHandler:  1:  j 1b
-I2C2_EV_IRQHandler:  1:  j 1b
-I2C2_ER_IRQHandler:  1:  j 1b
-SPI1_IRQHandler:  1:  j 1b
-SPI2_IRQHandler:  1:  j 1b
-USART1_IRQHandler:  1:  j 1b
-USART2_IRQHandler:  1:  j 1b
-USART3_IRQHandler:  1:  j 1b
-EXTI15_10_IRQHandler:  1:  j 1b
-RTCAlarm_IRQHandler:  1:  j 1b
-USBWakeUp_IRQHandler:  1:  j 1b
-TIM8_BRK_IRQHandler:  1:  j 1b
-TIM8_UP_IRQHandler:  1:  j 1b
-TIM8_TRG_COM_IRQHandler:  1:  j 1b
-TIM8_CC_IRQHandler:  1:  j 1b
-RNG_IRQHandler:  1:  j 1b
-FSMC_IRQHandler:  1:  j 1b
-SDIO_IRQHandler:  1:  j 1b
-TIM5_IRQHandler:  1:  j 1b
-SPI3_IRQHandler:  1:  j 1b
-UART4_IRQHandler:  1:  j 1b
-UART5_IRQHandler:  1:  j 1b
-TIM6_IRQHandler:  1:  j 1b
-TIM7_IRQHandler:  1:  j 1b
-DMA2_Channel1_IRQHandler:  1:  j 1b
-DMA2_Channel2_IRQHandler:  1:  j 1b
-DMA2_Channel3_IRQHandler:  1:  j 1b
-DMA2_Channel4_IRQHandler:  1:  j 1b
-DMA2_Channel5_IRQHandler:  1:  j 1b
-ETH_IRQHandler:  1:  j 1b
-ETH_WKUP_IRQHandler:  1:  j 1b
-CAN2_TX_IRQHandler:  1:  j 1b
-CAN2_RX0_IRQHandler:  1:  j 1b
-CAN2_RX1_IRQHandler:  1:  j 1b
-CAN2_SCE_IRQHandler:  1:  j 1b
-OTG_FS_IRQHandler:  1:  j 1b
-USBHSWakeup_IRQHandler:  1:  j 1b
-USBHS_IRQHandler:  1:  j 1b
-DVP_IRQHandler:  1:  j 1b
-UART6_IRQHandler:  1:  j 1b
-UART7_IRQHandler:  1:  j 1b
-UART8_IRQHandler:  1:  j 1b
-TIM9_BRK_IRQHandler:  1:  j 1b
-TIM9_UP_IRQHandler:  1:  j 1b
-TIM9_TRG_COM_IRQHandler:  1:  j 1b
-TIM9_CC_IRQHandler:  1:  j 1b
-TIM10_BRK_IRQHandler:  1:  j 1b
-TIM10_UP_IRQHandler:  1:  j 1b
-TIM10_TRG_COM_IRQHandler:  1:  j 1b
-TIM10_CC_IRQHandler:  1:  j 1b
-DMA2_Channel6_IRQHandler:  1:  j 1b
-DMA2_Channel7_IRQHandler:  1:  j 1b
-DMA2_Channel8_IRQHandler:  1:  j 1b
-DMA2_Channel9_IRQHandler:  1:  j 1b
-DMA2_Channel10_IRQHandler:  1:  j 1b
-DMA2_Channel11_IRQHandler:  1:  j 1b
+NMI_Handler:
+HardFault_Handler:
+Ecall_M_Mode_Handler:
+Ecall_U_Mode_Handler:
+Break_Point_Handler:
+SysTick_Handler:
+SW_handler:
+WWDG_IRQHandler:
+PVD_IRQHandler:
+TAMPER_IRQHandler:
+RTC_IRQHandler:
+FLASH_IRQHandler:
+RCC_IRQHandler:
+EXTI0_IRQHandler:
+EXTI1_IRQHandler:
+EXTI2_IRQHandler:
+EXTI3_IRQHandler:
+EXTI4_IRQHandler:
+DMA1_Channel1_IRQHandler:
+DMA1_Channel2_IRQHandler:
+DMA1_Channel3_IRQHandler:
+DMA1_Channel4_IRQHandler:
+DMA1_Channel5_IRQHandler:
+DMA1_Channel6_IRQHandler:
+DMA1_Channel7_IRQHandler:
+ADC1_2_IRQHandler:
+USB_HP_CAN1_TX_IRQHandler:
+USB_LP_CAN1_RX0_IRQHandler:
+CAN1_RX1_IRQHandler:
+CAN1_SCE_IRQHandler:
+EXTI9_5_IRQHandler:
+TIM1_BRK_IRQHandler:
+TIM1_UP_IRQHandler:
+TIM1_TRG_COM_IRQHandler:
+TIM1_CC_IRQHandler:
+TIM2_IRQHandler:
+TIM3_IRQHandler:
+TIM4_IRQHandler:
+I2C1_EV_IRQHandler:
+I2C1_ER_IRQHandler:
+I2C2_EV_IRQHandler:
+I2C2_ER_IRQHandler:
+SPI1_IRQHandler:
+SPI2_IRQHandler:
+USART1_IRQHandler:
+USART2_IRQHandler:
+USART3_IRQHandler:
+EXTI15_10_IRQHandler:
+RTCAlarm_IRQHandler:
+USBWakeUp_IRQHandler:
+TIM8_BRK_IRQHandler:
+TIM8_UP_IRQHandler:
+TIM8_TRG_COM_IRQHandler:
+TIM8_CC_IRQHandler:
+RNG_IRQHandler:
+FSMC_IRQHandler:
+SDIO_IRQHandler:
+TIM5_IRQHandler:
+SPI3_IRQHandler:
+UART4_IRQHandler:
+UART5_IRQHandler:
+TIM6_IRQHandler:
+TIM7_IRQHandler:
+DMA2_Channel1_IRQHandler:
+DMA2_Channel2_IRQHandler:
+DMA2_Channel3_IRQHandler:
+DMA2_Channel4_IRQHandler:
+DMA2_Channel5_IRQHandler:
+ETH_IRQHandler:
+ETH_WKUP_IRQHandler:
+CAN2_TX_IRQHandler:
+CAN2_RX0_IRQHandler:
+CAN2_RX1_IRQHandler:
+CAN2_SCE_IRQHandler:
+OTG_FS_IRQHandler:
+USBHSWakeup_IRQHandler:
+USBHS_IRQHandler:
+DVP_IRQHandler:
+UART6_IRQHandler:
+UART7_IRQHandler:
+UART8_IRQHandler:
+TIM9_BRK_IRQHandler:
+TIM9_UP_IRQHandler:
+TIM9_TRG_COM_IRQHandler:
+TIM9_CC_IRQHandler:
+TIM10_BRK_IRQHandler:
+TIM10_UP_IRQHandler:
+TIM10_TRG_COM_IRQHandler:
+TIM10_CC_IRQHandler:
+DMA2_Channel6_IRQHandler:
+DMA2_Channel7_IRQHandler:
+DMA2_Channel8_IRQHandler:
+DMA2_Channel9_IRQHandler:
+DMA2_Channel10_IRQHandler:
+DMA2_Channel11_IRQHandler:
+1:
+    j 1b
 
 
 	.section	.text.handle_reset,"ax",@progbits
@@ -373,7 +375,7 @@ handle_reset:
 
     /* Enable floating point and interrupt */
    	li t0, 0x7800
-   	csrs mstatus, t0
+   	csrw mstatus, t0
 
  	la t0, _vector_base
     ori t0, t0, 3           

bsp/wch/risc-v/ch569w-evt/board/startup_gcc.S

@@ -85,31 +85,32 @@ _vector_base:
     .weak   pmt_irq_handler
     .weak   ecdc_irq_handler
 
-nmi_handler:        j .L_rip
-hardfault_handler:  j .L_rip
-systick_handler:    j .L_rip
-swi_handler:        j .L_rip
-wdog_irq_handler:   j .L_rip
-tmr0_irq_handler:   j .L_rip
-gpio_irq_handler:   j .L_rip
-spi0_irq_handler:   j .L_rip
-usbss_irq_handler:  j .L_rip
-link_irq_handler:   j .L_rip
-tmr1_irq_handler:   j .L_rip
-tmr2_irq_handler:   j .L_rip
-uart0_irq_handler:  j .L_rip
-usbhs_irq_handler:  j .L_rip
-emmc_irq_handler:   j .L_rip
-dvp_irq_handler:    j .L_rip
-hspi_irq_handler:   j .L_rip
-spi1_irq_handler:   j .L_rip
-uart1_irq_handler:  j .L_rip
-uart2_irq_handler:  j .L_rip
-uart3_irq_handler:  j .L_rip
-serdes_irq_handler: j .L_rip
-eth_irq_handler:    j .L_rip
-pmt_irq_handler:    j .L_rip
-ecdc_irq_handler:   j .L_rip
+nmi_handler:
+hardfault_handler:
+systick_handler:
+swi_handler:
+wdog_irq_handler:
+tmr0_irq_handler:
+gpio_irq_handler:
+spi0_irq_handler:
+usbss_irq_handler:
+link_irq_handler:
+tmr1_irq_handler:
+tmr2_irq_handler:
+uart0_irq_handler:
+usbhs_irq_handler:
+emmc_irq_handler:
+dvp_irq_handler:
+hspi_irq_handler:
+spi1_irq_handler:
+uart1_irq_handler:
+uart2_irq_handler:
+uart3_irq_handler:
+serdes_irq_handler:
+eth_irq_handler:
+pmt_irq_handler:
+ecdc_irq_handler:
+    j .L_rip
 
 .L_rip:
     csrr t0, mepc
@@ -165,7 +166,7 @@ handle_reset:
 2:
 	/* leave all interrupt disabled */
     li t0, 0x1800
-    csrs mstatus, t0
+    csrw mstatus, t0
 	la t0, _vector_base
     ori t0, t0, 1
 	csrw mtvec, t0