110550093 lab6 7

lab5/src/lib/kernel/exception.c

@@ -82,6 +82,7 @@ void irq_handler_c(trapframe_t *tf)
             schedule();
     }
 
+    // only do signal handler when return to user mode (0b0000)
     if ((tf->spsr_el1 & 0b1100) == 0) {
         check_signal(tf);
     }
@@ -147,15 +148,12 @@ void el0_sync_router(trapframe_t *tf)
         kill(tf, (int)tf->regs[0]);
         break;
     case 8:
-        // uart_printf("syscall_no: %d\n", syscall_no);
         signal_register(tf->regs[0], (void (*)())tf->regs[1]);
         break;
     case 9:
-        // uart_printf("syscall_no: %d\n", syscall_no);
         signal_kill(tf->regs[0], tf->regs[1]);
         break;
     case 50:
-        // uart_printf("syscall_no: %d\n", syscall_no);
         signal_return(tf);
         break;
     default:
@@ -188,6 +186,7 @@ void el0_irq_router(trapframe_t *tf)
             schedule();
     }
 
+    // only do signal handler when return to user mode (0b0000)
     if ((tf->spsr_el1 & 0b1100) == 0) {
         check_signal(tf);
     }

lab5/src/lib/kernel/sched.c

@@ -69,7 +69,7 @@ thread_t *thread_create(void *start, int priority)
     r->used = 1;
     r->ustack_ptr = (char *)kmalloc(USTACK_SIZE);
     r->kstack_ptr = (char *)kmalloc(KSTACK_SIZE);
-    r->cpu_context.lr = (unsigned long)start;
+    r->cpu_context.lr = (unsigned long)start; // current thread's return address
     r->cpu_context.sp = (unsigned long)(r->ustack_ptr + USTACK_SIZE);
     r->cpu_context.fp = (unsigned long)(r->ustack_ptr + USTACK_SIZE);
 
@@ -190,11 +190,13 @@ int exec_thread(char *data, unsigned int datasize)
 
 void run_user_process()
 {
-    asm("msr tpidr_el1, %0\n\t"
-        "msr elr_el1, %1\n\t"
-        "msr spsr_el1, xzr\n\t"
+    asm("msr tpidr_el1, %0\n\t" // Hold the "kernel(el1)" thread structure information
+        "msr elr_el1, %1\n\t"   // When el0 -> el1, store return address for el1 -> el0
+        "msr spsr_el1, xzr\n\t" // Enable interrupt in EL0 -> Used for thread scheduler
         "msr sp_el0, %2\n\t"
         "mov sp, %3\n\t"
         "eret\n\t" ::"r"(&current->cpu_context),
-        "r"((unsigned long)current->data), "r"(current->cpu_context.sp), "r"(current->kstack_ptr + KSTACK_SIZE));
+        "r"((unsigned long)current->data), "r"(current->cpu_context.sp),
+        "r"(current->kstack_ptr + KSTACK_SIZE)); // sp is reference for the same el process. For example, el2 cannot use
+                                                 // sp_el2, it has to use sp to find its own stack.
 }

lab5/src/lib/kernel/syscall.c

@@ -161,6 +161,7 @@ void signal_return(trapframe_t *tf)
 {
     unsigned long signal_ustack; // to get the start address of the user stack
     if (tf->sp_el0 % USTACK_SIZE != 0) {
+        // if the stack uses stack, return to the start of the stack
         signal_ustack = tf->sp_el0 - (tf->sp_el0 % USTACK_SIZE);
     }
     else {

lab6/.gitignore

@@ -0,0 +1,3 @@
+.vscode
+build/
+img/

lab6/Makefile

@@ -0,0 +1,57 @@
+CC = aarch64-linux-gnu
+CFLAGS = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
+
+SRC_DIR = src
+INCLUDE_DIR = include
+KERNEL_DIR = kernel
+LIB_DIR = lib
+BOOT_DIR = bootloader
+BUILD_DIR = build
+IMG_DIR = img
+
+OBJECTS = $(patsubst $(SRC_DIR)/%.c, $(BUILD_DIR)/%.o, $(wildcard $(SRC_DIR)/*.c))
+OBJECTS += $(patsubst $(SRC_DIR)/%.S, $(BUILD_DIR)/%_s.o, $(wildcard $(SRC_DIR)/*.S))
+
+HEADERS = $(wildcard $(INCLUDE_DIR)/*.h)
+
+ELF_NAME = kernel8.elf
+IMG_NAME = kernel8.img
+BOOT_ELF_NAME = bootloader.elf
+BOOT_IMG_NAME = bootloader.img
+CPIO_FILE = initramfs.cpio
+
+all: clean $(OBJECTS) $(HEADERS)
+	$(CC)-ld -T $(SRC_DIR)/linker.ld -o $(BUILD_DIR)/$(ELF_NAME) $(OBJECTS)
+	$(CC)-objcopy -O binary $(BUILD_DIR)/$(ELF_NAME) $(IMG_DIR)/$(IMG_NAME)
+
+$(BUILD_DIR)/%.o: $(SRC_DIR)/%.c
+	@mkdir -p $(BUILD_DIR)
+	@mkdir -p $(IMG_DIR)
+	$(CC)-gcc $(CFLAGS) -c $< -o $@
+
+$(BUILD_DIR)/%_s.o: $(SRC_DIR)/%.S
+	$(CC)-gcc $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -rf $(BUILD_DIR) $(IMG_DIR)
+
+dump:
+	qemu-system-aarch64 -M raspi3b -kernel $(IMG_DIR)/$(IMG_NAME) -initrd $(CPIO_FILE) -display none -d in_asm -dtb bcm2710-rpi-3-b-plus.dtb
+
+run: all
+	qemu-system-aarch64 -M raspi3b -kernel $(IMG_DIR)/$(IMG_NAME) -initrd $(CPIO_FILE) -display none -serial null -serial stdio -s -dtb bcm2710-rpi-3-b-plus.dtb
+
+tty:
+	qemu-system-aarch64 -M raspi3b -kernel $(IMG_DIR)/$(BOOT_IMG_NAME) -initrd $(CPIO_FILE) -display none -serial null -serial pty
+
+upload:
+	sudo python3 upload.py
+
+cpio:
+	cd rootfs && find . | cpio -o -H newc > ../$(CPIO_FILE)
+
+screen:
+	sudo screen /dev/ttyUSB0 115200
+
+userprog:
+	cd user_program && make clean && make

lab6/bootloader/config.txt

@@ -0,0 +1,3 @@
+kernel=bootloader.img
+arm_64bit=1
+initramfs initramfs.cpio 0x8000000

lab6/bootloader/include/bcm2837/rpi_base.h

@@ -0,0 +1,6 @@
+#ifndef	_RPI_BASE_H_
+#define	_RPI_BASE_H_
+
+#define PERIPHERAL_BASE 0x3F000000
+
+#endif  /*_RPI_BASE_H_ */

lab6/bootloader/include/bcm2837/rpi_gpio.h

@@ -0,0 +1,25 @@
+#ifndef _RPI_GPIO_H_
+#define _RPI_GPIO_H_
+
+#include "bcm2837/rpi_base.h"
+
+#define GPFSEL0         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200000))
+#define GPFSEL1         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200004))
+#define GPFSEL2         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200008))
+#define GPFSEL3         ((volatile unsigned int*)(PERIPHERAL_BASE+0x0020000C))
+#define GPFSEL4         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200010))
+#define GPFSEL5         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200014))
+#define GPSET0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x0020001C))
+#define GPSET1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200020))
+#define GPCLR0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200028))
+#define GPLEV0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200034))
+#define GPLEV1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200038))
+#define GPEDS0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200040))
+#define GPEDS1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200044))
+#define GPHEN0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200064))
+#define GPHEN1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200068))
+#define GPPUD           ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200094))
+#define GPPUDCLK0       ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200098))
+#define GPPUDCLK1       ((volatile unsigned int*)(PERIPHERAL_BASE+0x0020009C))
+
+#endif /*_RPI_GPIO_H_*/

lab6/bootloader/include/bcm2837/rpi_uart1.h

@@ -0,0 +1,19 @@
+#ifndef	_RPI_UART1_H_
+#define	_RPI_UART1_H_
+
+#include "bcm2837/rpi_base.h"
+
+#define AUX_ENABLES     ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215004))
+#define AUX_MU_IO_REG   ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215040))
+#define AUX_MU_IER_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215044))
+#define AUX_MU_IIR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215048))
+#define AUX_MU_LCR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x0021504C))
+#define AUX_MU_MCR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215050))
+#define AUX_MU_LSR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215054))
+#define AUX_MU_MSR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215058))
+#define AUX_MU_SCRATCH  ((volatile unsigned int*)(PERIPHERAL_BASE+0x0021505C))
+#define AUX_MU_CNTL_REG ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215060))
+#define AUX_MU_STAT_REG ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215064))
+#define AUX_MU_BAUD_REG ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215068))
+
+#endif  /*_RPI_UART1_H_ */

lab6/bootloader/include/power.h

@@ -0,0 +1,8 @@
+#ifndef	_POWER_H_
+#define	_POWER_H_
+
+#define PM_PASSWORD 0x5a000000
+#define PM_RSTC     0x3F10001c
+#define PM_WDOG     0x3F100024
+
+#endif /*_POWER_H_*/

lab6/bootloader/include/shell.h

@@ -0,0 +1,23 @@
+#ifndef _SHELL_H_
+#define _SHELL_H_
+
+#define CLI_MAX_CMD 3
+#define CMD_MAX_LEN 32
+#define MSG_MAX_LEN 128
+
+typedef struct CLI_CMDS
+{
+    char command[CMD_MAX_LEN];
+    char help[MSG_MAX_LEN];
+} CLI_CMDS;
+
+void cli_cmd_clear(char*, int);
+void cli_cmd_read(char*);
+void cli_cmd_exec(char*);
+void cli_print_banner();
+
+void do_cmd_help();
+void do_cmd_loadimg();
+void do_cmd_reboot();
+
+#endif /* _SHELL_H_ */

lab6/bootloader/include/uart1.h

@@ -0,0 +1,11 @@
+#ifndef	_UART1_H_
+#define	_UART1_H_
+
+void uart_init();
+char uart_getc();
+char uart_recv();
+void uart_send(unsigned int c);
+int  uart_puts(char* fmt, ...);
+void uart_2hex(unsigned int d);
+
+#endif /*_UART1_H_*/

lab6/bootloader/include/utils.h

@@ -0,0 +1,11 @@
+#ifndef _UTILS_H_
+#define _UTILS_H_
+
+#define VSPRINT_MAX_BUF_SIZE 128
+
+unsigned int sprintf(char *dst, char* fmt, ...);
+unsigned int vsprintf(char *dst,char* fmt, __builtin_va_list args);
+
+int  strcmp(const char*, const char*);
+
+#endif /* _UTILS_H_ */

lab6/bootloader/makefile

@@ -0,0 +1,42 @@
+ARMGNU ?= aarch64-linux-gnu
+
+CFLAGS = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
+ASMFLAGS = -Iinclude
+
+BUILD_DIR = build
+SRC_DIR = src
+#---------------------------------------------------------------------------------------
+
+C_FILES = $(wildcard $(SRC_DIR)/*.c)
+ASM_FILES = $(wildcard $(SRC_DIR)/*.S)
+OBJ_FILES = $(C_FILES:$(SRC_DIR)/%.c=$(BUILD_DIR)/%_c.o)
+OBJ_FILES += $(ASM_FILES:$(SRC_DIR)/%.S=$(BUILD_DIR)/%_s.o)
+
+DEP_FILES = $(OBJ_FILES:%.o=%.d)
+-include $(DEP_FILES)
+
+$(BUILD_DIR)/%_c.o: $(SRC_DIR)/%.c
+	@mkdir -p $(@D)
+	$(ARMGNU)-gcc $(CFLAGS) -MMD -c $< -o $@
+
+$(BUILD_DIR)/%_s.o: $(SRC_DIR)/%.S
+	$(ARMGNU)-gcc $(ASMFLAGS) -MMD -c $< -o $@
+
+bootloader.img: $(SRC_DIR)/link.ld $(OBJ_FILES)
+	$(ARMGNU)-ld -T $(SRC_DIR)/link.ld -o $(BUILD_DIR)/bootloader.elf  $(OBJ_FILES)
+	$(ARMGNU)-objcopy $(BUILD_DIR)/bootloader.elf -O binary bootloader.img
+
+all: bootloader.img
+
+clean:
+	rm -rf $(BUILD_DIR) *.img
+
+run_std:
+	qemu-system-aarch64 -M raspi3b -kernel bootloader.img -serial null -serial stdio -initrd initramfs.cpio -dtb bcm2710-rpi-3-b-plus.dtb
+
+run_pty:
+	qemu-system-aarch64 -M raspi3b -kernel bootloader.img -serial null -serial pty -initrd initramfs.cpio -dtb bcm2710-rpi-3-b-plus.dtb
+
+debug:
+	qemu-system-aarch64 -M raspi3b -kernel bootloader.img -display none -S -s
+

lab6/bootloader/src/boot.S

@@ -0,0 +1,52 @@
+/* ARMv8 Assembly Instruction */
+/**
+
+mov x0, x1
+    sets: x0 = x1
+ldr x0, <addr>
+    load 32bits from <addr> to x0
+ldr w0, <addr>
+    load 64bits from <addr> to w0
+cbz x0, <label>
+    if x0 == 0, jump to <label>
+cbnz x0, <label>
+    if x0 != 0, jump to <label>
+str x0 [x1] #8
+    store x0 in addr<x1> then x1=x1+8
+b   <label>
+    jump to <label>
+bl  <label>
+    jump to <label> and copies bl's next instruction into link register
+wfe
+    Wait for event, core in low-power state (power on, clk off)
+
+**/
+
+// x0 is used for dtb physical address
+.section ".text.boot"
+
+.global _start
+
+_start:
+setup_stack:
+    ldr     x1, =_stack_top
+    mov     sp, x1
+
+setup_bss:
+    ldr     x1, =_bss_top
+    ldr     w2, =_bss_size
+
+init_bss:
+    cbz     w2, run_main
+    str     xzr, [x1], #8
+    sub     w2, w2, #1
+    cbnz    w2, init_bss
+
+run_main:
+    ldr     x1, =_dtb
+    str     x0, [x1], #8
+    bl      main
+
+proc_hang:
+    wfe
+    b       proc_hang

lab6/bootloader/src/link.ld

@@ -0,0 +1,30 @@
+_heap_stack_size = 1M;  
+# heap_size 0x100000
+
+SECTIONS
+{
+    . = 0x80000;
+    _start = .;
+    .text : { *(.text.boot) *(.text) }
+    .rodata : { *(.rodata) }
+    .data : { *(.data) }
+    .bss : {
+        _bss_top = .;
+        *(.bss) 
+    }
+    _bss_size = SIZEOF(.bss) >> 3;
+    .heap : {
+        . = ALIGN(8);
+        _heap_top = .;
+    } 
+    . = . + _heap_stack_size;
+    .stack : {
+        . = ALIGN(8);
+        _stack_top = .;
+    }
+    _end = .;
+
+    . = 0x3000000;
+    _bootloader_relocated_addr = 0x3000000;
+}
+__code_size = (_end - _start);