feat(user): add user-space build system and init process to test fork/wait

16 files changed, 391 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index 4f89bac..3e06e89 100644
--- a/Makefile
+++ b/Makefile
@@ -3,29 +3,56 @@ CC      := $(TOOLCHAIN_PREFIX)gcc
 CXX     := $(TOOLCHAIN_PREFIX)g++
 LD      := $(TOOLCHAIN_PREFIX)ld
 OBJCOPY := $(TOOLCHAIN_PREFIX)objcopy
+OBJDUMP := $(TOOLCHAIN_PREFIX)objdump
 
 BUILD_DIR := build
 SRC_DIR   := src
 
-CFLAGS   := -Wall -Wextra -O2 -ffreestanding -nostdlib -mcmodel=medany -Iinclude
+CFLAGS   := -Wall -Wextra -O2 -g -ffreestanding -nostdlib -mcmodel=medany -Iinclude
 CXXFLAGS := $(CFLAGS) -fno-exceptions -fno-rtti -fno-use-cxa-atexit
-
 LINKER_SCRIPT := link.ld
 
-SRCS_S   := $(shell find $(SRC_DIR) -name "*.S")
-SRCS_CXX := $(shell find $(SRC_DIR) -name "*.cc")
+UPROGS_SRC := $(SRC_DIR)/user/init.cc
+UPROGS_OBJ := $(BUILD_DIR)/user/init.o
+ULIB_OBJ   := $(BUILD_DIR)/user/usys.o
+USER_LD    := $(SRC_DIR)/user/user.ld
+INITCODE_BIN := $(BUILD_DIR)/user/initcode
+
+SRCS_S   := $(shell find $(SRC_DIR) -name "*.S" -not -path "$(SRC_DIR)/user/*")
+SRCS_CXX := $(shell find $(SRC_DIR) -name "*.cc" -not -path "$(SRC_DIR)/user/*")
 OBJS     := $(SRCS_S:%.S=$(BUILD_DIR)/%.o) $(SRCS_CXX:%.cc=$(BUILD_DIR)/%.o)
 
 TARGET   := $(BUILD_DIR)/kernel.elf
 
-.PHONY: all clean run
+.PHONY: all clean run debug
 
 all: $(TARGET)
 
+$(BUILD_DIR)/user/%.o: $(SRC_DIR)/user/%.cc
+	@mkdir -p $(dir $@)
+	@echo "  U_CXX   $<"
+	@$(CXX) $(CXXFLAGS) -c $< -o $@
+
+$(BUILD_DIR)/user/%.o: $(SRC_DIR)/user/%.S
+	@mkdir -p $(dir $@)
+	@echo "  U_AS    $<"
+	@$(CC) $(CFLAGS) -c $< -o $@
+
+$(INITCODE_BIN): $(UPROGS_OBJ) $(ULIB_OBJ) $(USER_LD)
+	@echo "  U_LD    $@"
+	@$(LD) -T $(USER_LD) -o $@.out $(UPROGS_OBJ) $(ULIB_OBJ)
+	@$(OBJCOPY) -S -O binary $@.out $@
+	@$(OBJDUMP) -S $@.out > $@.asm
+
 $(TARGET): $(OBJS) $(LINKER_SCRIPT)
 	@echo "  LD      $@"
 	@$(LD) -T $(LINKER_SCRIPT) -o $@ $(OBJS)
 
+$(BUILD_DIR)/src/kernel/initcode.o: $(SRC_DIR)/kernel/initcode.S $(INITCODE_BIN)
+	@mkdir -p $(dir $@)
+	@echo "  AS_INC  $<"
+	@$(CC) $(CFLAGS) -c $< -o $@
+
 $(BUILD_DIR)/%.o: %.S
 	@mkdir -p $(dir $@)
 	@echo "  AS      $<"
@@ -41,5 +68,10 @@ run: $(TARGET)
 	@qemu-system-riscv64 -machine virt -nographic \
 		-kernel $(TARGET) -m 128M
 
+debug: $(TARGET)
+	@echo "  QEMU (DEBUG)  Waiting for GDB..."
+	@qemu-system-riscv64 -machine virt -nographic \
+		-kernel $(TARGET) -m 128M -s -S
+
 clean:
-	rm -rf $(BUILD_DIR)
\ No newline at end of file
+	rm -rf $(BUILD_DIR)
diff --git a/build/kernel.elf b/build/kernel.elf
index 996720e..860775f 100755
--- a/build/kernel.elf
+++ b/build/kernel.elf
diff --git a/build/src/kernel/initcode.o b/build/src/kernel/initcode.o
new file mode 100644
index 0000000..e53a8a5
--- /dev/null
+++ b/build/src/kernel/initcode.o
diff --git a/build/src/kernel/proc/proc.o b/build/src/kernel/proc/proc.o
index f4bbe8f..d22780c 100644
--- a/build/src/kernel/proc/proc.o
+++ b/build/src/kernel/proc/proc.o
diff --git a/build/user/init.o b/build/user/init.o
new file mode 100644
index 0000000..d32ad08
--- /dev/null
+++ b/build/user/init.o
diff --git a/build/user/initcode b/build/user/initcode
new file mode 100755
index 0000000..511a518
--- /dev/null
+++ b/build/user/initcode
diff --git a/build/user/initcode.asm b/build/user/initcode.asm
new file mode 100644
index 0000000..e3a1185
--- /dev/null
+++ b/build/user/initcode.asm
@@ -0,0 +1,215 @@
+
+build/user/initcode.out:     file format elf64-littleriscv
+
+
+Disassembly of section .text:
+
+0000000000000000 <_start>:
+#include "user/user.h"
+
+int main();
+
+extern "C" void _start()
+{
+   0:	1141                	addi	sp,sp,-16
+   2:	e406                	sd	ra,8(sp)
+    exit(main());
+   4:	004000ef          	jal	8 <main>
+
+0000000000000008 <main>:
+}
+
+int main()
+{
+   8:	1141                	addi	sp,sp,-16
+   a:	e406                	sd	ra,8(sp)
+    int pid = fork();
+   c:	060000ef          	jal	6c <fork>
+
+    if (pid < 0)
+  10:	00054f63          	bltz	a0,2e <main+0x26>
+    {
+        write(1, "Fork failed\n", 12);
+        exit(1);
+    }
+
+    if (pid == 0)
+  14:	e905                	bnez	a0,44 <main+0x3c>
+    {
+        write(1, "Hello from Child!\n", 18);
+  16:	4649                	li	a2,18
+  18:	00000597          	auipc	a1,0x0
+  1c:	12058593          	addi	a1,a1,288 # 138 <putc+0x24>
+  20:	4505                	li	a0,1
+  22:	072000ef          	jal	94 <write>
+        exit(0);
+  26:	4501                	li	a0,0
+  28:	04c000ef          	jal	74 <exit>
+        write(1, "Parent waiting...\n", 18);
+        wait(0);
+        write(1, "Parent: Child exited.\n", 22);
+    }
+
+    while (1);
+  2c:	a001                	j	2c <main+0x24>
+        write(1, "Fork failed\n", 12);
+  2e:	4631                	li	a2,12
+  30:	00000597          	auipc	a1,0x0
+  34:	0f058593          	addi	a1,a1,240 # 120 <putc+0xc>
+  38:	4505                	li	a0,1
+  3a:	05a000ef          	jal	94 <write>
+        exit(1);
+  3e:	4505                	li	a0,1
+  40:	034000ef          	jal	74 <exit>
+        write(1, "Parent waiting...\n", 18);
+  44:	4649                	li	a2,18
+  46:	00000597          	auipc	a1,0x0
+  4a:	10a58593          	addi	a1,a1,266 # 150 <putc+0x3c>
+  4e:	4505                	li	a0,1
+  50:	044000ef          	jal	94 <write>
+        wait(0);
+  54:	4501                	li	a0,0
+  56:	026000ef          	jal	7c <wait>
+        write(1, "Parent: Child exited.\n", 22);
+  5a:	4659                	li	a2,22
+  5c:	00000597          	auipc	a1,0x0
+  60:	10c58593          	addi	a1,a1,268 # 168 <putc+0x54>
+  64:	4505                	li	a0,1
+  66:	02e000ef          	jal	94 <write>
+  6a:	b7c9                	j	2c <main+0x24>
+
+000000000000006c <fork>:
+    name: \
+        li a7, SYS_ ## name; \
+        ecall; \
+        ret
+
+SYSCALL(fork)
+  6c:	4889                	li	a7,2
+  6e:	00000073          	ecall
+  72:	8082                	ret
+
+0000000000000074 <exit>:
+SYSCALL(exit)
+  74:	488d                	li	a7,3
+  76:	00000073          	ecall
+  7a:	8082                	ret
+
+000000000000007c <wait>:
+SYSCALL(wait)
+  7c:	4891                	li	a7,4
+  7e:	00000073          	ecall
+  82:	8082                	ret
+
+0000000000000084 <pipe>:
+SYSCALL(pipe)
+  84:	4895                	li	a7,5
+  86:	00000073          	ecall
+  8a:	8082                	ret
+
+000000000000008c <read>:
+SYSCALL(read)
+  8c:	4899                	li	a7,6
+  8e:	00000073          	ecall
+  92:	8082                	ret
+
+0000000000000094 <write>:
+SYSCALL(write)
+  94:	48c5                	li	a7,17
+  96:	00000073          	ecall
+  9a:	8082                	ret
+
+000000000000009c <close>:
+SYSCALL(close)
+  9c:	48d9                	li	a7,22
+  9e:	00000073          	ecall
+  a2:	8082                	ret
+
+00000000000000a4 <kill>:
+SYSCALL(kill)
+  a4:	489d                	li	a7,7
+  a6:	00000073          	ecall
+  aa:	8082                	ret
+
+00000000000000ac <exec>:
+SYSCALL(exec)
+  ac:	48a1                	li	a7,8
+  ae:	00000073          	ecall
+  b2:	8082                	ret
+
+00000000000000b4 <open>:
+SYSCALL(open)
+  b4:	48c1                	li	a7,16
+  b6:	00000073          	ecall
+  ba:	8082                	ret
+
+00000000000000bc <mknod>:
+SYSCALL(mknod)
+  bc:	48c9                	li	a7,18
+  be:	00000073          	ecall
+  c2:	8082                	ret
+
+00000000000000c4 <unlink>:
+SYSCALL(unlink)
+  c4:	48cd                	li	a7,19
+  c6:	00000073          	ecall
+  ca:	8082                	ret
+
+00000000000000cc <fstat>:
+SYSCALL(fstat)
+  cc:	48a5                	li	a7,9
+  ce:	00000073          	ecall
+  d2:	8082                	ret
+
+00000000000000d4 <link>:
+SYSCALL(link)
+  d4:	48d1                	li	a7,20
+  d6:	00000073          	ecall
+  da:	8082                	ret
+
+00000000000000dc <mkdir>:
+SYSCALL(mkdir)
+  dc:	48d5                	li	a7,21
+  de:	00000073          	ecall
+  e2:	8082                	ret
+
+00000000000000e4 <chdir>:
+SYSCALL(chdir)
+  e4:	48a9                	li	a7,10
+  e6:	00000073          	ecall
+  ea:	8082                	ret
+
+00000000000000ec <dup>:
+SYSCALL(dup)
+  ec:	48ad                	li	a7,11
+  ee:	00000073          	ecall
+  f2:	8082                	ret
+
+00000000000000f4 <getpid>:
+SYSCALL(getpid)
+  f4:	48b1                	li	a7,12
+  f6:	00000073          	ecall
+  fa:	8082                	ret
+
+00000000000000fc <sbrk>:
+SYSCALL(sbrk)
+  fc:	48b5                	li	a7,13
+  fe:	00000073          	ecall
+ 102:	8082                	ret
+
+0000000000000104 <sleep>:
+SYSCALL(sleep)
+ 104:	48b9                	li	a7,14
+ 106:	00000073          	ecall
+ 10a:	8082                	ret
+
+000000000000010c <uptime>:
+SYSCALL(uptime)
+ 10c:	48bd                	li	a7,15
+ 10e:	00000073          	ecall
+ 112:	8082                	ret
+
+0000000000000114 <putc>:
+ 114:	4885                	li	a7,1
+ 116:	00000073          	ecall
+ 11a:	8082                	ret
diff --git a/build/user/initcode.out b/build/user/initcode.out
new file mode 100755
index 0000000..0667728
--- /dev/null
+++ b/build/user/initcode.out
diff --git a/build/user/usys.o b/build/user/usys.o
new file mode 100644
index 0000000..9ac9e11
--- /dev/null
+++ b/build/user/usys.o
diff --git a/include/kernel/syscall.h b/include/kernel/syscall.h
index 571741e..222f2f4 100644
--- a/include/kernel/syscall.h
+++ b/include/kernel/syscall.h
@@ -23,4 +23,6 @@
 #define SYS_mkdir   21
 #define SYS_close   22
 
-void syscall();
\ No newline at end of file
+#ifndef __ASSEMBLER__
+void syscall();
+#endif
\ No newline at end of file
diff --git a/include/user/user.h b/include/user/user.h
new file mode 100644
index 0000000..7ab4923
--- /dev/null
+++ b/include/user/user.h
@@ -0,0 +1,29 @@
+#pragma once
+typedef unsigned long long uint64;
+
+extern "C" {
+    int fork();
+    int exit(int status);
+    int wait(uint64 status_addr);
+    int pipe(int p[]);
+    int write(int fd, const void *buf, int n);
+    int read(int fd, void *buf, int n);
+    int close(int fd);
+    int kill(int pid);
+    int exec(char *, char **);
+    int open(const char *, int);
+    int mknod(const char *, short, short);
+    int unlink(const char *);
+    int fstat(int fd, void *st);
+    int link(const char *, const char *);
+    int mkdir(const char *);
+    int chdir(const char *);
+    int dup(int fd);
+    int getpid();
+    char *sbrk(int n);
+    int sleep(int ticks);
+    int uptime();
+
+    
+    void putc(char c);
+}
\ No newline at end of file
diff --git a/src/kernel/initcode.S b/src/kernel/initcode.S
new file mode 100644
index 0000000..8b56ce6
--- /dev/null
+++ b/src/kernel/initcode.S
@@ -0,0 +1,8 @@
+.section .rodata
+.global initcode_start
+.global initcode_end
+.align 4
+
+initcode_start:
+    .incbin "build/user/initcode"
+initcode_end:
diff --git a/src/kernel/proc/proc.cc b/src/kernel/proc/proc.cc
index 15a28b4..008f740 100644
--- a/src/kernel/proc/proc.cc
+++ b/src/kernel/proc/proc.cc
@@ -23,13 +23,8 @@ struct spinlock proc_lock;
 
 int nextpid = 1;
 
-
-uchar initcode[] = {
-    0x13, 0x05, 0x50, 0x05, // li a0, 85 ('U')
-    0x93, 0x08, 0x10, 0x00, // li a7, 1  (SYS_putc)
-    0x73, 0x00, 0x00, 0x00, // ecall
-    0x6f, 0xf0, 0x5f, 0xff  // j loop (-12)
-};
+extern char initcode_start[];
+extern char initcode_end[];
 
 struct Proc *myproc()
 {
@@ -277,7 +272,9 @@ namespace ProcManager
         }
 
         p->pagetable = VM::uvmcreate();
-        VM::uvminit(p->pagetable, initcode, sizeof(initcode));
+        
+        uint64 initcode_sz = initcode_end - initcode_start;
+        VM::uvminit(p->pagetable, (uchar *)initcode_start, initcode_sz);
         p->sz = PGSIZE;
 
         if (VM::mappages(p->pagetable, TRAPFRAME, PGSIZE,
@@ -402,6 +399,6 @@ namespace ProcManager
         }
     }
 
-    
+
 
 }
\ No newline at end of file
diff --git a/src/user/init.cc b/src/user/init.cc
new file mode 100644
index 0000000..3c42adf
--- /dev/null
+++ b/src/user/init.cc
@@ -0,0 +1,34 @@
+#include "user/user.h"
+
+int main();
+
+extern "C" void _start()
+{
+    exit(main());
+}
+
+int main()
+{
+    int pid = fork();
+
+    if (pid < 0)
+    {
+        write(1, "Fork failed\n", 12);
+        exit(1);
+    }
+
+    if (pid == 0)
+    {
+        write(1, "Hello from Child!\n", 18);
+        exit(0);
+    }
+    else
+    {
+        write(1, "Parent waiting...\n", 18);
+        wait(0);
+        write(1, "Parent: Child exited.\n", 22);
+    }
+
+    while (1);
+    return 0;
+}
\ No newline at end of file
diff --git a/src/user/user.ld b/src/user/user.ld
new file mode 100644
index 0000000..2111b14
--- /dev/null
+++ b/src/user/user.ld
@@ -0,0 +1,27 @@
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+
+SECTIONS
+{
+  . = 0x0;
+  
+  .text : {
+    *(.text.entry)
+    *(.text .text.*)
+  }
+
+  .rodata : {
+    . = ALIGN(16);
+    *(.rodata .rodata.*)
+  }
+
+  .data : {
+    . = ALIGN(16);
+    *(.data .data.*)
+  }
+
+  .bss : {
+    . = ALIGN(16);
+    *(.bss .bss.*)
+  }
+}
\ No newline at end of file
diff --git a/src/user/usys.S b/src/user/usys.S
new file mode 100644
index 0000000..e805d82
--- /dev/null
+++ b/src/user/usys.S
@@ -0,0 +1,31 @@
+#include "kernel/syscall.h"
+
+#define SYSCALL(name) \
+    .global name; \
+    name: \
+        li a7, SYS_ ## name; \
+        ecall; \
+        ret
+
+SYSCALL(fork)
+SYSCALL(exit)
+SYSCALL(wait)
+SYSCALL(pipe)
+SYSCALL(read)
+SYSCALL(write)
+SYSCALL(close)
+SYSCALL(kill)
+SYSCALL(exec)
+SYSCALL(open)
+SYSCALL(mknod)
+SYSCALL(unlink)
+SYSCALL(fstat)
+SYSCALL(link)
+SYSCALL(mkdir)
+SYSCALL(chdir)
+SYSCALL(dup)
+SYSCALL(getpid)
+SYSCALL(sbrk)
+SYSCALL(sleep)
+SYSCALL(uptime)
+SYSCALL(putc)
\ No newline at end of file