post: arm smp

_posts/2023-8-30-arm-smp-demo.markdown

@@ -0,0 +1,292 @@
+---
+layout: post
+title:  "ARM架构bare-metal多核程序示例"
+categories: Technology
+tags: 树莓派 raspberry pi 多核 arm zh smp qemu aarch64 体系结构 en bare-metal 裸金属
+author: Calinyara
+description:
+---
+
+<br>
+
+- ***boot.S***
+
+```c
+.global _start
+.section .text.boot, "ax"
+
+_start:
+    mrs x0, mpidr_el1
+    and x0, x0, #3
+
+    mov x6, x0
+    mov x1, #0x0
+    add x2, x1, #0x400000
+    lsl x6, x6, #18
+    sub x3, x2, x6
+    mov sp, x3
+
+    bl uart_init
+
+    mrs x0, mpidr_el1
+    and x0, x0, #3
+    cbz x0, core0
+    cmp x0, #1
+    b.eq core1
+    cmp x0, #2
+    b.eq core2
+    cmp x0, #3
+    b.eq core3
+
+core0:
+    bl print0
+    b hang
+
+core1:
+    bl print1
+    b hang
+
+core2:
+    bl print2
+    b hang
+
+core3:
+    bl print3
+    b hang
+
+hang:
+    wfi
+    b hang
+```
+
+<br>
+
+- ***main.c***
+
+```c
+extern void delay(unsigned long);
+extern void put32(unsigned long, unsigned int);
+extern unsigned int get32(unsigned long);
+extern int get_el(void);
+
+#define PBASE 0x3F000000
+#define GPFSEL1	  (PBASE + 0x00200004)
+#define GPSET0	  (PBASE + 0x0020001C)
+#define GPCLR0	  (PBASE + 0x00200028)
+#define GPPUD	  (PBASE + 0x00200094)
+#define GPPUDCLK0 (PBASE + 0x00200098)
+
+#define AUX_ENABLES	(PBASE + 0x00215004)
+#define AUX_MU_IO_REG	(PBASE + 0x00215040)
+#define AUX_MU_IER_REG	(PBASE + 0x00215044)
+#define AUX_MU_IIR_REG	(PBASE + 0x00215048)
+#define AUX_MU_LCR_REG	(PBASE + 0x0021504C)
+#define AUX_MU_MCR_REG	(PBASE + 0x00215050)
+#define AUX_MU_LSR_REG	(PBASE + 0x00215054)
+#define AUX_MU_MSR_REG	(PBASE + 0x00215058)
+#define AUX_MU_SCRATCH	(PBASE + 0x0021505C)
+#define AUX_MU_CNTL_REG (PBASE + 0x00215060)
+#define AUX_MU_STAT_REG (PBASE + 0x00215064)
+#define AUX_MU_BAUD_REG (PBASE + 0x00215068)
+
+void uart_send_char(char c)
+{
+	while (1) {
+		if (get32(AUX_MU_LSR_REG) & 0x20)
+			break;
+	}
+	put32(AUX_MU_IO_REG, c);
+}
+
+void uart_init(void)
+{
+	unsigned int selector;
+
+	selector = get32(GPFSEL1);
+	selector &= ~(7 << 12);
+	selector |= 2 << 12;
+	selector &= ~(7 << 15);
+	selector |= 2 << 15;
+	put32(GPFSEL1, selector);
+
+	put32(GPPUD, 0);
+	delay(150);
+	put32(GPPUDCLK0, (1 << 14) | (1 << 15));
+	delay(150);
+	put32(GPPUDCLK0, 0);
+
+	put32(AUX_ENABLES, 1);
+	put32(AUX_MU_CNTL_REG, 0);
+	put32(AUX_MU_IER_REG, 0);
+	put32(AUX_MU_LCR_REG, 3);
+	put32(AUX_MU_MCR_REG, 0);
+	put32(AUX_MU_BAUD_REG, 270);
+
+	put32(AUX_MU_CNTL_REG, 3);
+}
+
+void print0() {
+	for(int j = 0; j <= 3; j++) {
+		for(int i = 0; i <= 200000000; i++) {
+			if (i == 1)
+				uart_send_char('0');
+		}
+	}
+}
+
+void print1() {
+	for(int j = 0; j <= 3; j++) {
+		for(int i = 0; i <= 200000000; i++) {
+			if (i == 10000000)
+				uart_send_char('1');
+		}
+	}		
+}
+
+void print2() {
+	for(int j = 0; j <= 3; j++) {
+		for(int i = 0; i <= 200000000; i++) {
+			if (i == 90000000)
+				uart_send_char('2');
+		}
+	}		
+}
+
+void print3() {
+	for(int j = 0; j <= 3; j++) {
+		for(int i = 0; i <= 200000000; i++) {
+			if (i == 80000000)
+				uart_send_char('3');
+		}
+	}		
+}
+```
+
+<br>
+
+- ***utils.S***
+
+```c
+.globl get_el
+get_el:
+	mrs x0, CurrentEL
+	lsr x0, x0, #2
+	ret
+
+.globl put32
+put32:
+	str w1,[x0]
+	ret
+
+.globl get32
+get32:
+	ldr w0,[x0]
+	ret
+
+.globl delay
+delay:
+	subs x0, x0, #1
+	bne delay
+	ret
+```
+
+<br>
+
+- ***Makefile***
+
+```makefile
+ARMGNU ?= aarch64-linux-gnu
+
+COPS = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
+ASMOPS = -Iinclude
+
+BUILD_DIR = build
+SRC_DIR = .
+
+all : arm_smp
+
+run : arm_smp
+	qemu-system-aarch64 -M raspi3b -nographic -serial null -serial mon:stdio -kernel kernel8.elf
+
+clean :
+	rm -rf $(BUILD_DIR) *.img *.bin *.elf
+
+$(BUILD_DIR)/%_c.o: $(SRC_DIR)/%.c
+	mkdir -p $(@D)
+	$(ARMGNU)-gcc $(COPS) -MMD -c $< -o $@
+
+$(BUILD_DIR)/%_s.o: $(SRC_DIR)/%.S
+	$(ARMGNU)-gcc $(ASMOPS) -MMD -c $< -o $@
+
+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)
+
+arm_smp: $(SRC_DIR)/linker.ld $(OBJ_FILES)
+	 $(ARMGNU)-ld -T $(SRC_DIR)/linker.ld -o kernel8.elf  $(OBJ_FILES)
+```
+
+<br>
+
+- ***linker.ld***
+
+```c
+ENTRY(_start)
+
+SECTIONS {
+    . = 0x80000;
+
+    .text : {
+        *(.text.boot)
+        *(.text)
+    }
+
+    .data : {
+        *(.data)
+    }
+}
+```
+
+<br>
+
+```shell
+$ make run
+0132013201320132
+```
+
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