fix port_systick_config bug

arch/risc-v/common/tos_cpu.c

@@ -7,9 +7,6 @@
 #include <tos.h>
 #include <riscv_encoding.h>
 
-// soc code shoud not put here
-#define __SYSTEM_CLOCK_108M_PLL_HXTAL           (uint32_t)(108000000)
-uint32_t SystemCoreClock = __SYSTEM_CLOCK_108M_PLL_HXTAL;
 
 __KERNEL__ void cpu_systick_init(k_cycle_t cycle_per_tick)
 {
@@ -20,7 +17,6 @@ __KERNEL__ void cpu_systick_init(k_cycle_t cycle_per_tick)
 __KERNEL__ void cpu_init(void) {
     k_cpu_cycle_per_tick = TOS_CFG_CPU_CLOCK / k_cpu_tick_per_second;
     cpu_systick_init(k_cpu_cycle_per_tick);
-	//TODO
 }
 
 __API__ cpu_cpsr_t tos_cpu_cpsr_save(void)
@@ -122,27 +118,29 @@ __KERNEL__ k_stack_t *cpu_task_stk_init(void *entry,
 
 void cpu_trap_entry(cpu_data_t cause, cpu_context_t *regs)
 {
-	int ddd = cause;
 	while(1) {
-		ddd++;
+		// TODO
 	}
 }
 
 void SysTick_IRQHandler() {
-	//asm("csrs mip, %0"::"r"(MIP_MTIP));
-
 	port_systick_config(k_cpu_cycle_per_tick);
-#if 1
 	if(tos_knl_is_running()) {
 	  tos_knl_irq_enter();
 	  tos_tick_handler();
 	  tos_knl_irq_leave();
 	}
-#endif
 }
 
 void cpu_irq_entry(cpu_data_t irq, cpu_context_t *regs)
 {
+#if 1
+	if(irq != 7) {
+		return;
+	}
+
+	SysTick_IRQHandler();
+#else
 	void (*irq_handler)();
 	extern void (*handler_vector_table[])();
 
@@ -152,6 +150,7 @@ void cpu_irq_entry(cpu_data_t irq, cpu_context_t *regs)
 	}
 
 	(*irq_handler)();
+#endif
 }
 
 __API__ uint32_t tos_cpu_clz(uint32_t val)

arch/risc-v/rv32i/port_c.c

@@ -6,140 +6,41 @@
  */
 #include "riscv_encoding.h"
 #include <tos.h>
+
 #define CLINT_CTRL_ADDR 0x2000000
 #define CLINT_MSIP		0x0000
 #define CLINT_MTIMECMP 	0x4000
 #define CLINT_MTIME 	0xBFF8
 
-
-static uint32_t mtime_lo(void)
-{
-  return *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME);
-}
-
-
-static uint32_t mtime_hi(void)
-{
-  return *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME + 4);
-}
-
-uint64_t get_mtime_val()
-{
-  while (1) {
-    uint32_t hi = mtime_hi();
-    uint32_t lo = mtime_lo();
-    uint32_t nhi = mtime_hi();
-    if (hi == nhi) {
-      return (((uint64_t)hi) << 32) | lo;
-    } {
-    	uint32_t a = hi;
-    	uint32_t b = nhi;
-    }
-  }
-}
-
-void set_mtimecmp_lo(uint32_t v)
-{
-	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP) = v;
-}
-
-void set_mtimecmp_hi(uint32_t v)
-{
-	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = v;
-}
-
-void set_mtimecmp_val(uint64_t v)
-{
-    uint32_t hi = (v >> 32) & 0xFFFFFFFF;
-    uint32_t lo = (v >>  0) & 0xFFFFFFFF;
-    set_mtimecmp_lo(0xFFFFFFFF); // No smaller than old value.
-    set_mtimecmp_hi(hi);         // No smaller than new value.
-    set_mtimecmp_lo(lo);         // New value.
-}
-
-
-
 __PORT__ void port_systick_config(uint32_t cycle_per_tick)
 {
-#if 0
-	asm("csrc mie, %0"::"r"(MIP_MTIP));
 
-#if 1
-	uint64_t mtime = get_mtime_val();
-#else
-	static uint64_t last_mtime = 0;
-	if(last_mtime == 0) {
-		last_mtime = get_mtime_val();
-	}
-	uint64_t mtime = get_mtime_val();
-	if((mtime - last_mtime)/cycle_per_tick >= 4) {
-		mtime = last_mtime+2*cycle_per_tick;
-	}
-	last_mtime = mtime;
-#endif
-	uint64_t mtimecmp;
-	do {
-		tick_inc();
-		mtimecmp = ((uint64_t)tos_get_tick())* cycle_per_tick;
-	} while(mtimecmp <= mtime);
-
-	set_mtimecmp_val(mtimecmp);
-
-	asm("csrs mie, %0"::"r"(MIP_MTIP));
-#endif
-#if 0
-	  clear_csr(mie, MIP_MTIP);
-	  static uint64_t then = 0;
-
-	  volatile uint64_t * mtime       = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIME);
-	  volatile uint64_t * mtimecmp    = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
-	  if(then != 0)  {
-	    //next timer irq is 1 second from previous
-	    then += 1*cycle_per_tick;
-	  } else{ //first time setting the timer
-	    uint64_t now = *mtime;
-	    then = now + 1*cycle_per_tick;
-	  }
-	  *mtimecmp = then;
-
-	  set_csr(mie, MIP_MTIP);
-#endif
-	//asm("csrc mie, %0"::"r"(MIP_MTIP));
-#if 0
-	uint64_t next_tick = get_mtime_val();
-	next_tick += cycle_per_tick;
-	set_mtimecmp_val(next_tick);
-#endif
-
-#if 0
-	uint64_t new_tick = get_mtime_val() + cycle_per_tick;
-	uint64_t tick = 0;
-	if(new_tick - next_tick > 50000) {
-		tick = get_mtime_val() + cycle_per_tick;
-	}
-	next_tick = new_tick;
-	set_mtimecmp_val(next_tick);
-#endif
-
-#if 1
-	// this is illegal in ricsv-32
 	// it cost cpu read two times, first mtime_lo and then mtime_hi
 	// if mtime_lo == 0xFFFFFFFF and mtime_hi = 0 at first read
 	// then mtime_lo == 0 and mtime_hi = 1 at next read
 	// the result will be  0x1FFFFFFFF, not 0x100000000
-	//*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = 0xFFFFFFFF;
+	uint64_t mtime = 0;
-	//*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = 0xFFFFFFFF;
+	while(1) {
+		uint32_t mtime_hi = *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME + 4);
+		uint32_t mtime_lo = *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME + 0);
+		uint32_t mtime_hn = *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME + 4);
+		if(mtime_hi == mtime_hn) {
+			mtime += ((uint64_t)mtime_hi << 32) | mtime_lo;
+			break;
+		}
+	}
 
-	uint64_t mtime = *(volatile uint64_t *)(CLINT_CTRL_ADDR + CLINT_MTIME);
+	// just set mtime to mtimecmp does not accurately reflect the passage of time
+	// cause some time cost on the path to deal with the interrupt
+	// so, we need to to fix the value with a multiple of cycle_per_tick
+	uint64_t tick = mtime / cycle_per_tick;
+	uint64_t mtimecmp = (tick + 1) * cycle_per_tick;
 
-	mtime += cycle_per_tick;
 
-	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = (mtime >> 32) & 0xFFFFFFFF;
+	// write to mtimecmp register
-	asm("csrc mip, %0"::"r"(MIP_MTIP));
+	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = 0xFFFFFFFF;
-	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = (mtime >>  0) & 0xFFFFFFFF;
+	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = 0xFFFFFFFF & (mtimecmp >> 32);
-	//asm("csrc mip, %0"::"r"(MIP_MTIP));
+	*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = 0xFFFFFFFF & (mtimecmp >>  0);
-#endif
-	//asm("csrs mie, %0"::"r"(MIP_MTIP));
 }
 
 __PORT__ void port_systick_priority_set(uint32_t prio)

arch/risc-v/rv32i/port_s.S

@@ -4,6 +4,10 @@
 .global port_cpsr_save
 .global port_cpsr_restore
 
+.global port_systick_resume
+.global port_systick_suspend
+.global port_systick_pending_reset
+
 .global port_sched_start
 .global port_context_switch
 .global port_irq_context_switch
@@ -26,7 +30,6 @@ port_int_enable:
 .type port_cpsr_save, %function
 port_cpsr_save:
 	csrrci	a0, mstatus, MSTATUS_MIE
-	#csrrci  a0, mstatus, MSTATUS_MPIE
 	ret
 
 .type port_cpsr_restore, %function
@@ -34,6 +37,25 @@ port_cpsr_restore:
 	csrw	mstatus, a0
 	ret
 
+.type port_systick_resume, %function
+port_systick_resume:
+    li t0, MIE_MTIE
+    csrs mie, t0
+    ret
+
+.type port_systick_suspend, %function
+port_systick_suspend:
+    li t0, MIE_MTIE
+    csrc mie, t0
+    ret
+
+.type port_systick_pending_reset, %function
+port_systick_pending_reset:
+    li t0, MIP_MTIP
+    csrc mip, t0
+    ret
+
+
 
 #define REGBYTES	4
 #define LOAD		lw
@@ -405,3 +427,5 @@ port_irq_context_switch:
 
 irq_context_return:
 	ret
+
+

arch/risc-v/rv32i/start.S

@@ -11,16 +11,8 @@ _start:
 
 	la t0, machine_trap_entry
 	csrw mtvec, t0
-#if 1
+
-	// before kernel run, the stack is unused
-	// so just borrow to use
-	la t0, k_idle_task_stk_addr
-	lw t1, k_idle_task_stk_size
-	add sp, t0, t1
-#else
-	// uncomment in link.ld
 	la sp, _stack_top
-#endif
 
 	/* Load data section */
 	la a0, _load_data
@@ -47,163 +39,3 @@ init_finish:
 	call main
 __die:
 	j __die
-
-
-
-.section .text
-    .weak  eclic_msip_handler
-    .weak  eclic_mtip_handler
-    .weak  SysTick_IRQHandler
-    .weak  eclic_bwei_handler
-    .weak  eclic_pmovi_handler
-    .weak  WWDGT_IRQHandler
-    .weak  LVD_IRQHandler
-    .weak  TAMPER_IRQHandler
-    .weak  RTC_IRQHandler
-    .weak  FMC_IRQHandler
-    .weak  RCU_IRQHandler
-    .weak  EXTI0_IRQHandler
-    .weak  EXTI1_IRQHandler
-    .weak  EXTI2_IRQHandler
-    .weak  EXTI3_IRQHandler
-    .weak  EXTI4_IRQHandler
-    .weak  DMA0_Channel0_IRQHandler
-    .weak  DMA0_Channel1_IRQHandler
-    .weak  DMA0_Channel2_IRQHandler
-    .weak  DMA0_Channel3_IRQHandler
-    .weak  DMA0_Channel4_IRQHandler
-    .weak  DMA0_Channel5_IRQHandler
-    .weak  DMA0_Channel6_IRQHandler
-    .weak  ADC0_1_IRQHandler
-    .weak  CAN0_TX_IRQHandler
-    .weak  CAN0_RX0_IRQHandler
-    .weak  CAN0_RX1_IRQHandler
-    .weak  CAN0_EWMC_IRQHandler
-    .weak  EXTI5_9_IRQHandler
-    .weak  TIMER0_BRK_IRQHandler
-    .weak  TIMER0_UP_IRQHandler
-    .weak  TIMER0_TRG_CMT_IRQHandler
-    .weak  TIMER0_Channel_IRQHandler
-    .weak  TIMER1_IRQHandler
-    .weak  TIMER2_IRQHandler
-    .weak  TIMER3_IRQHandler
-    .weak  I2C0_EV_IRQHandler
-    .weak  I2C0_ER_IRQHandler
-    .weak  I2C1_EV_IRQHandler
-    .weak  I2C1_ER_IRQHandler
-    .weak  SPI0_IRQHandler
-    .weak  SPI1_IRQHandler
-    .weak  USART0_IRQHandler
-    .weak  USART1_IRQHandler
-    .weak  USART2_IRQHandler
-    .weak  EXTI10_15_IRQHandler
-    .weak  RTC_Alarm_IRQHandler
-    .weak  USBFS_WKUP_IRQHandler
-    .weak  EXMC_IRQHandler
-    .weak  TIMER4_IRQHandler
-    .weak  SPI2_IRQHandler
-    .weak  UART3_IRQHandler
-    .weak  UART4_IRQHandler
-    .weak  TIMER5_IRQHandler
-    .weak  TIMER6_IRQHandler
-    .weak  DMA1_Channel0_IRQHandler
-    .weak  DMA1_Channel1_IRQHandler
-    .weak  DMA1_Channel2_IRQHandler
-    .weak  DMA1_Channel3_IRQHandler
-    .weak  DMA1_Channel4_IRQHandler
-    .weak  CAN1_TX_IRQHandler
-    .weak  CAN1_RX0_IRQHandler
-    .weak  CAN1_RX1_IRQHandler
-    .weak  CAN1_EWMC_IRQHandler
-    .weak  USBFS_IRQHandler
-
-.global handler_vector_table
-.align  2
-handler_vector_table:
-	.word     0
-    .word     0
-    .word     0
-    .word     eclic_msip_handler
-    .word     0
-    .word     0
-    .word  	  0
-    .word  	  SysTick_IRQHandler
-    .word  	  0
-    .word  	  0
-    .word  	  0
-    .word  	  0
-    .word  	  0
-    .word  	  0
-    .word  	  0
-    .word 	  0
-    .word  	  0
-    .word  	  eclic_bwei_handler
-    .word  	  eclic_pmovi_handler
-    .word  	  WWDGT_IRQHandler
-	.word     LVD_IRQHandler
-	.word     TAMPER_IRQHandler
-	.word     RTC_IRQHandler
-	.word     FMC_IRQHandler
-	.word     RCU_IRQHandler
-	.word     EXTI0_IRQHandler
-	.word     EXTI1_IRQHandler
-	.word     EXTI2_IRQHandler
-	.word     EXTI3_IRQHandler
-	.word     EXTI4_IRQHandler
-	.word     DMA0_Channel0_IRQHandler
-	.word     DMA0_Channel1_IRQHandler
-	.word     DMA0_Channel2_IRQHandler
-	.word     DMA0_Channel3_IRQHandler
-	.word     DMA0_Channel4_IRQHandler
-	.word     DMA0_Channel5_IRQHandler
-	.word     DMA0_Channel6_IRQHandler
-	.word     ADC0_1_IRQHandler
-	.word     CAN0_TX_IRQHandler
-	.word     CAN0_RX0_IRQHandler
-	.word     CAN0_RX1_IRQHandler
-	.word     CAN0_EWMC_IRQHandler
-	.word     EXTI5_9_IRQHandler
-	.word     TIMER0_BRK_IRQHandler
-	.word     TIMER0_UP_IRQHandler
-	.word     TIMER0_TRG_CMT_IRQHandler
-	.word     TIMER0_Channel_IRQHandler
-	.word     TIMER1_IRQHandler
-	.word     TIMER2_IRQHandler
-	.word     TIMER3_IRQHandler
-	.word     I2C0_EV_IRQHandler
-	.word     I2C0_ER_IRQHandler
-	.word     I2C1_EV_IRQHandler
-	.word     I2C1_ER_IRQHandler
-	.word     SPI0_IRQHandler
-	.word     SPI1_IRQHandler
-	.word     USART0_IRQHandler
-	.word     USART1_IRQHandler
-	.word     USART2_IRQHandler
-	.word     EXTI10_15_IRQHandler
-	.word     RTC_Alarm_IRQHandler
-	.word     USBFS_WKUP_IRQHandler
-    .word     0
-    .word     0
-    .word     0
-    .word     0
-	.word     0
-	.word     EXMC_IRQHandler
-	.word     0
-	.word     TIMER4_IRQHandler
-	.word     SPI2_IRQHandler
-	.word     UART3_IRQHandler
-	.word     UART4_IRQHandler
-	.word     TIMER5_IRQHandler
-	.word     TIMER6_IRQHandler
-	.word     DMA1_Channel0_IRQHandler
-	.word     DMA1_Channel1_IRQHandler
-	.word     DMA1_Channel2_IRQHandler
-	.word     DMA1_Channel3_IRQHandler
-	.word     DMA1_Channel4_IRQHandler
-    .word     0
-    .word     0
-	.word     CAN1_TX_IRQHandler
-	.word     CAN1_RX0_IRQHandler
-	.word     CAN1_RX1_IRQHandler
-	.word     CAN1_EWMC_IRQHandler
-	.word     USBFS_IRQHandler

board/QEMU_Spike/eclipse/hello_world/.cproject

@@ -134,8 +134,6 @@
                                     <listOptionValue builtIn="false" value="&quot;${workspace_loc:/hello_world/TencentOS_tiny/kernel/pm/include}&quot;"/>
                                     									
                                     <listOptionValue builtIn="false" value="&quot;${workspace_loc:/hello_world/Inc}&quot;"/>
-                                    									
-                                    <listOptionValue builtIn="false" value="&quot;${workspace_loc:/hello_world/TencentOS_tiny/osal/cmsis_os}&quot;"/>
                                     								
                                 </option>
                                 								

board/QEMU_Spike/eclipse/hello_world/.project

@@ -39,11 +39,6 @@
 			<type>2</type>
 			<locationURI>$%7BPARENT-4-PROJECT_LOC%7D/kernel</locationURI>
 		</link>
-		<link>
-			<name>TencentOS_tiny/osal</name>
-			<type>2</type>
-			<locationURI>$%7BPARENT-4-PROJECT_LOC%7D/osal</locationURI>
-		</link>
 		<link>
 			<name>TencentOS_tiny/arch/risc-v</name>
 			<type>2</type>

board/QEMU_Spike/eclipse/hello_world/.settings/language.settings.xml

@@ -11,7 +11,7 @@
             			
             <provider-reference id="org.eclipse.cdt.managedbuilder.core.MBSLanguageSettingsProvider" ref="shared-provider"/>
             			
-            <provider class="org.eclipse.cdt.managedbuilder.language.settings.providers.GCCBuiltinSpecsDetector" console="false" env-hash="1353384052355236260" id="ilg.gnumcueclipse.managedbuild.cross.riscv.GCCBuiltinSpecsDetector" keep-relative-paths="false" name="CDT RISC-V Cross GCC Built-in Compiler Settings" parameter="${COMMAND} ${FLAGS} ${cross_toolchain_flags} -E -P -v -dD &quot;${INPUTS}&quot;" prefer-non-shared="true">
+            <provider class="org.eclipse.cdt.managedbuilder.language.settings.providers.GCCBuiltinSpecsDetector" console="false" env-hash="1380923165007189689" id="ilg.gnumcueclipse.managedbuild.cross.riscv.GCCBuiltinSpecsDetector" keep-relative-paths="false" name="CDT RISC-V Cross GCC Built-in Compiler Settings" parameter="${COMMAND} ${FLAGS} ${cross_toolchain_flags} -E -P -v -dD &quot;${INPUTS}&quot;" prefer-non-shared="true">
                 				
                 <language-scope id="org.eclipse.cdt.core.gcc"/>
                 				

board/QEMU_Spike/eclipse/hello_world/Inc/tos_config.h

@@ -42,8 +42,7 @@
 
 #define TOS_CFG_CPU_TICK_PER_SECOND 1000u // 配置TencentOS tiny的tick频率
 
-extern uint32_t SystemCoreClock;
+#define TOS_CFG_CPU_CLOCK 108000000 // 配置TencentOS tiny CPU频率
-#define TOS_CFG_CPU_CLOCK (SystemCoreClock) // 配置TencentOS tiny CPU频率
 
 #define TOS_CFG_TIMER_AS_PROC 1u // 配置是否将TIMER配置成函数模式
 

board/QEMU_Spike/eclipse/hello_world/Src/main.c

@@ -6,40 +6,21 @@
  */
 
 #include "tos.h"
-#include "riscv_encoding.h"
 
-#define RISCV_MSTATUS_MIE               (1<<3)        /*machine-level interrupt bit*/
+#define TASK_SIZE 512
-#define RISCV_MSTATUS_MPIE              (1<<7)        /*machine-level pre interrupt bit*/
-#define RISCV_MSTATUS_MPP               (0x3<<10)     /*machine-level MPP bit*/
-
-#define RISCV_MSTATUS_MPP_MPIE          (RISCV_MSTATUS_MPIE | RISCV_MSTATUS_MPP)
-void port_sched_start();
-#define STACK_SIZE 512
-char stack[STACK_SIZE];
-void debug_task() {
-	int idle = 0;
-	int cnt = 0;
-	while(1) {
-		idle++;
-		cnt++;
-	}
-}
-
-#include "cmsis_os.h"
-
-//task1
-#define TASK1_STK_SIZE 512
-void task1(void *pdata);
 k_task_t k_task_task1;
-uint8_t k_task1_stk[TASK1_STK_SIZE];
+k_task_t k_task_task2;
-int shit = 123;
+uint8_t k_task1_stk[TASK_SIZE];
+uint8_t k_task2_stk[TASK_SIZE];
+
+int share = 123;
 void task1(void *pdata)
 {
-	int c = 0;
+	int t1 = 0;
 	while(1)
 	{
-		c++;
+		t1++;
-		shit++;
+		share++;
 		//k_tick_t delay = tos_millisec2tick(10);
 		//tos_task_delay(delay);
 		tos_task_yield();
@@ -48,50 +29,34 @@ void task1(void *pdata)
 	}
 }
 
-void task2(void *pdata);
-k_task_t k_task_task2;
-uint8_t k_task2_stk[TASK1_STK_SIZE];
 void task2(void *pdata)
 {
-	int c = 0;
+	int t2 = 0;
 	while(1)
 	{
-		c--;
+		t2--;
-		shit--;
+		share--;
-		//osDelay(10);
+		//tos_task_delay(10);
 		tos_task_yield();
 		asm("wfi;");
 	}
 }
 
-uint32_t *stack_sp;
-
 int main(void)
 {
-	osKernelInitialize();
+	tos_knl_init();
-#if 0
+
-	while(1) {
+	tos_task_create(&k_task_task1, "task1", task1, NULL, 3, k_task1_stk, TASK_SIZE, 0);
-		asm("csrs mie, %0"::"r"(MIE_MTIE));
+	tos_task_create(&k_task_task2, "task2", task2, NULL, 3, k_task2_stk, TASK_SIZE, 0);
-		asm("csrs mstatus, %0"::"r"(MSTATUS_MIE));
+
-		asm("wfi;");
+	tos_knl_start();
-	}
+
-#endif
-	tos_task_create(&k_task_task1, "task1", task1, NULL, 3, k_task1_stk, TASK1_STK_SIZE, 0);
-	tos_task_create(&k_task_task2, "task2", task2, NULL, 3, k_task2_stk, TASK1_STK_SIZE, 0);
-	osKernelStart();
-	uint32_t *sp = stack+STACK_SIZE - 4;
-	sp = (uint32_t*)(((uint32_t)sp) & 0xFFFFFFF0);
 
-	*(sp - 22) = 0x0ACE0ACE;	// Reg R0: argument
-	*(sp - 30) = 0x1234ABCD;	// ra
-	*(sp - 31) = debug_task;
-	*(sp - 32) = RISCV_MSTATUS_MPIE | RISCV_MSTATUS_MPP;
-	sp -= 32;
-	stack_sp = sp;
-	port_sched_start();
 	int c = 0;
-	while(1) {
+	while(1)
+	{
 		c++;
+		asm("wfi;");
 	}
 
 }

board/QEMU_Spike/eclipse/hello_world/link.ld

@@ -41,12 +41,10 @@ SECTIONS
   . = ALIGN(8);
   PROVIDE( end = . );
   
-  /*
+  _stack_size = 128;
-  _stack_size = 256;
   .stack ORIGIN(RAM) + LENGTH(RAM) - _stack_size :
   {
     . = _stack_size;  
     PROVIDE( _stack_top = . ); 
   } >RAM AT>RAM
-  */ 
 }