Set development environment with UART debug output for aarch64

Makefile

@@ -0,0 +1,90 @@
+# environment
+
+AARCH64_TOOLCHAIN ?= aarch64-linux-gnu
+
+
+# Shortcuts
+
+CC=clang --target=aarch64-none-elf -mcpu=cortex-a57
+LD=ld.lld
+OBJCOPY=$(AARCH64_TOOLCHAIN)-objcopy --target elf64-littleaarch64
+
+CFLAGS += -O0
+CFLAGS += -g
+#CFLAGS += -nostdlib
+#CFLAGS += -march=armv8-a
+#CFLAGS += -std=c99
+#CFLAGS += -pedantic
+#CFLAGS += -Wall
+#CFLAGS += -Wmissing-prototypes
+#CFLAGS += -Wstrict-prototypes
+#CFLAGS += -Wold-style-definition
+
+BUILD_DIR=build
+
+
+# Files
+
+KERNEL_MEMMAP = aarch64/memmap
+
+KERNEL_SOURCES = \
+  aarch64/boot.s \
+  sys/main.c \
+  sys/uart.c \
+
+KERNEL_LIST := $(wildcard $(KERNEL_SOURCES))
+KERNEL_OBJS := $(addsuffix .o, $(addprefix $(BUILD_DIR)/, ${KERNEL_LIST}))
+
+all: kernel
+
+
+# compilation 
+
+kernel: $(BUILD_DIR)/kernel.elf # $(BUILD_DIR)/kernel.sym
+
+$(BUILD_DIR)/kernel.elf: $(KERNEL_OBJS)
+	$(info linking target: $@)
+	$(LD) -T$(KERNEL_MEMMAP) -nostdlib $^ -o $@
+	$(info done: $@)
+
+$(BUILD_DIR)/kernel.bin: $(BUILD_DIR)/kernel.elf
+	$(OBJCOPY) -O binary $< $@
+
+$(BUILD_DIR)/kernel.sym: $(BUILD_DIR)/kernel.elf
+	$(OBJCOPY) --only-keep-debug $< $@
+	$(OBJCOPY) --strip-debug $@
+
+$(BUILD_DIR)/%.o: %
+	$(info compiling file: $<)
+	@mkdir -p $(dir ./$(BUILD_DIR)/$<)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+
+.PHONY: clean run
+
+# helpers
+QEMU_CMD = \
+  qemu-system-aarch64 \
+    -M virt \
+    -cpu cortex-a57 \
+    -nographic \
+    -smp 4 \
+    -m 4096 \
+    -kernel build/kernel.elf \
+    -serial stdio \
+    -monitor none \
+
+
+clean:
+	rm -Rf ./$(BUILD_DIR)/*
+
+run: kernel
+	$(QEMU_CMD)
+
+
+debug: kernel
+	$(QEMU_CMD) -S -gdb tcp::1234 & \
+  gdb-multiarch -q \
+  -ex 'file build/kernel.elf' \
+  -ex 'target remote localhost:1234'
+	kill %1

aarch64/boot.s

@@ -0,0 +1,18 @@
+	.globl _start
+
+_start:
+
+	mrs x0, mpidr_el1       // Check CPU ID
+	mov x1, 0xC1000000
+	bic x0, x0, x1
+	cbz x0, set_stack
+	b   idle
+
+set_stack:
+	ldr x30, =stack_ptr  // defined in sys/memmap
+	mov sp,  x30
+	bl  k_main
+
+idle:
+	b idle
+

aarch64/memmap

@@ -0,0 +1,16 @@
+ENTRY(_start)
+
+SECTIONS
+{
+	/* For some reason qemu UART doesn't work with smaller address */
+	. = 0x40000000; 
+
+	.boot . : { boot.o(.text) }
+	.text : { *(.text) }
+	.data : { *(.data) }
+	.bss : { *(.bss COMMON) }
+
+	. = ALIGN(8);
+	. = . + 0x1000;
+	stack_ptr = . ;
+}

kernel/arm64/Makefile

@@ -1,34 +0,0 @@
-ASM=clang
-TARGET=aarch64-none-elf
-CPU=cortex-a57
-LD=ld.lld
-OBJCOPY=objcopy --target elf64-littleaarch64
-
-all: build/core.bin build/core.elf
-
-# compilation -----------------------------------------------------------------
-
-build/core.o: core/core.s
-	$(ASM) -c -triple --target=$(TARGET) -mcpu=$(CPU) -O0  -g $< -o $@
-
-build/uart.o: core/uart.s
-	$(ASM) -c --target=$(TARGET) -mcpu=$(CPU) -O0  -g $< -o $@
-
-# ELF -------------------------------------------------------------------------
-
-build/core.elf: build/core.o build/uart.o
-	$(LD) -Tcore/core.ld $^ -o $@
-
-# BIN -------------------------------------------------------------------------
-
-build/core.bin: build/core.elf
-	$(OBJCOPY) -O binary $< $@
-
-build/core.sym: build/core.elf
-	$(OBJCOPY) --only-keep-debug $< $@
-	$(OBJCOPY) --strip-debug build/core.elf
-
-# Clean -----------------------------------------------------------------------
-
-clean:
-		rm -f build/*

kernel/arm64/core.ld

@@ -1,12 +0,0 @@
-ENTRY(_core_init)
-
-SECTIONS
-{
-  . = 0x40000000;
-  .text : { *(.text) }
-  .data : { *(.text) }
-  .bss : { *(.bss COMMON) }
-  . = ALIGN(10);
-  . = . + 0x1000;
-  stack_ptr = . ;
-}

kernel/arm64/uart.s

@@ -1,93 +0,0 @@
-# file    : uart.s
-# project : Löwe OS
-# authors : Elias Löwe <elias@lowenware.com>
-
-# address of UART for virt device in qemu
-
-# -----------------------------------------------------------------------------
-
-  .global _uart_putc    # print single character uart
-  .global _uart_putx    # print integer in HEX format to uart
-  .global _uart_puts    # print null-terminated string to uart
-
-# -----------------------------------------------------------------------------
-
-  .text
-
-# helper to avoid extra data moving
-# @x1 character print
-uart_putc:
-  STP     x2, lr, [sp, -16]!
-
-  MOV     x2, 0x09000000              # set UART address
-  STRB    w1, [x2]                    # put character out
-
-  LDP     x2, lr, [sp], 16
-  RET
-
-# -----------------------------------------------------------------------------
-
-
-# print character to uart
-# @x0 character print
-_uart_putc:
-  STR     lr, [sp, -16]!
-
-  MOV     x1, x0                      # set arguments
-  BL      uart_putc                   # put character out
-
-  LDR     lr, [sp], 16
-  RET
-  
-
-# -----------------------------------------------------------------------------
-
-# @x0 integer to print
-_uart_putx:
-  STP     lr, x3, [sp, -32]!
-  STP     x0, x1, [sp, 16]
-
-  LDR     x3, =60                     # init bits counter 64-4
-
-1:
-  LSR     x1, x0, x3                  # shift to digit
-  AND     x1, x1, 0xF                 # keep only digit
-  CMP     x1, 9                       # compare it to 9
-  BLS     2f                          # less or equal
-  ADD     x1, x1, 0x37                # turn into ASCII HEX char
-  B       3f                          # continue to output
-
-2:
-  ADD     x1, x1, 0x30                # turn into ASCII num char
-
-3:
-  BL      uart_putc                   # output carachter
-  CBZ     x3, 0f                      # if counter == 0 return
-  SUB     x3, x3, 4                   # otherwise subtract counter by 4
-  B       1b                          # repeat
-
-0:
-  LDP     lr, x3, [sp], 16
-  LDP     x0, x1, [sp], 16
-  RET
-
-# -----------------------------------------------------------------------------
-
-# @x0 pointer to string
-
-_uart_puts:
-  STR     lr, [sp, -16]!
-  STP     x0, x1, [sp, -16]!
-
-1:
-  LDRB    w1, [x0], 1                  # load byte of string from address in x0
-  CBZ     w1, 0f                       # return if zero
-  BL      uart_putc                    # put charcter out
-  B       1b                           # loop
-
-0:
-  LDP     x0, x1, [sp], 16
-  LDR     lr, [sp], 16
-  RET
-
-# -----------------------------------------------------------------------------

sys/main.c

@@ -0,0 +1,34 @@
+/******************************************************************************
+ *
+ *                Copyright (c) 2017-2019 by Löwenware Ltd
+ *             Please, refer LICENSE file for legal information
+ *
+ ******************************************************************************/
+
+/**
+ * @file main.c
+ * @author Ilja Kartašov <ik@lowenware.com>
+ * @brief 
+ *
+ * @see https://lowenware.com/
+ */
+
+#include "uart.h"
+
+
+void
+k_main(void);
+
+
+void
+k_main(void)
+{
+	uart_init();
+
+	uart_puts((unsigned char *) "Lowe OS\n");
+
+	for (;;) {
+		__asm__("WFE");
+	}
+}
+

sys/uart.c

@@ -0,0 +1,41 @@
+/******************************************************************************
+ *
+ *                Copyright (c) 2017-2019 by Löwenware Ltd
+ *             Please, refer LICENSE file for legal information
+ *
+ ******************************************************************************/
+
+/**
+ * @file uart.c
+ * @author Ilja Kartašov <ik@lowenware.com>
+ * @brief 
+ *
+ * @see https://lowenware.com/
+ */
+
+#include "uart.h"
+
+volatile unsigned int *UART0 = (unsigned int *)UART_BASE;
+
+
+void
+uart_init(void)
+{
+
+}
+
+
+void
+uart_putc(unsigned char c)
+{
+	*UART0 = (unsigned int) c;
+}
+
+
+void
+uart_puts(const unsigned char *s)
+{
+	while(*s) {
+		*UART0 = (unsigned int) *(s++);
+	}
+}

sys/uart.h

@@ -0,0 +1,33 @@
+/******************************************************************************
+ *
+ *                Copyright (c) 2017-2019 by Löwenware Ltd
+ *             Please, refer LICENSE file for legal information
+ *
+ ******************************************************************************/
+
+/**
+ * @file uart.h
+ * @author Ilja Kartašov <ik@lowenware.com>
+ * @brief 
+ *
+ * @see https://lowenware.com/
+ */
+
+#ifndef UART_H_8AFC47F9_2953_42C1_A5C1_1AE5A1F52CD0
+#define UART_H_8AFC47F9_2953_42C1_A5C1_1AE5A1F52CD0
+
+
+#define UART_BASE 0x09000000
+
+void
+uart_init(void);
+
+
+void
+uart_putc(unsigned char c);
+
+
+void
+uart_puts(const unsigned char *s);
+
+#endif /* !UART_H */

sys/uart.s

@@ -0,0 +1,93 @@
+// file    : uart.s
+// project : Löwe OS
+// authors : Elias Löwe <elias@lowenware.com>
+
+// address of UART for virt device in qemu
+
+// -----------------------------------------------------------------------------
+
+  .global _uart_putc    // print single character uart
+  .global _uart_putx    // print integer in HEX format to uart
+  .global _uart_puts    // print null-terminated string to uart
+
+// -----------------------------------------------------------------------------
+
+  .text
+
+// helper to avoid extra data moving
+// @x1 character print
+uart_putc:
+  STP     x2, lr, [sp, -16]!
+
+  MOV     x2, 0x09000000              // set UART address
+  STRB    w1, [x2]                    // put character out
+
+  LDP     x2, lr, [sp], 16
+  RET
+
+// -----------------------------------------------------------------------------
+
+
+// print character to uart
+// @x0 character print
+_uart_putc:
+  STR     lr, [sp, -16]!
+
+  MOV     x1, x0                      // set arguments
+  BL      uart_putc                   // put character out
+
+  LDR     lr, [sp], 16
+  RET
+  
+
+// -----------------------------------------------------------------------------
+
+// @x0 integer to print
+_uart_putx:
+  STP     lr, x3, [sp, -32]!
+  STP     x0, x1, [sp, 16]
+
+  LDR     x3, =60                     // init bits counter 64-4
+
+1:
+  LSR     x1, x0, x3                  // shift to digit
+  AND     x1, x1, 0xF                 // keep only digit
+  CMP     x1, 9                       // compare it to 9
+  BLS     2f                          // less or equal
+  ADD     x1, x1, 0x37                // turn into ASCII HEX char
+  B       3f                          // continue to output
+
+2:
+  ADD     x1, x1, 0x30                // turn into ASCII num char
+
+3:
+  BL      uart_putc                   // output carachter
+  CBZ     x3, 0f                      // if counter == 0 return
+  SUB     x3, x3, 4                   // otherwise subtract counter by 4
+  B       1b                          // repeat
+
+0:
+  LDP     lr, x3, [sp], 16
+  LDP     x0, x1, [sp], 16
+  RET
+
+// -----------------------------------------------------------------------------
+
+// @x0 pointer to string
+
+_uart_puts:
+  STR     lr, [sp, -16]!
+  STP     x0, x1, [sp, -16]!
+
+1:
+  LDRB    w1, [x0], 1                  // load byte of string from address in x0
+  CBZ     w1, 0f                       // return if zero
+  BL      uart_putc                    // put charcter out
+  B       1b                           // loop
+
+0:
+  LDP     x0, x1, [sp], 16
+  LDR     lr, [sp], 16
+  RET
+
+// -----------------------------------------------------------------------------