Draft: lab 5 failed

Makefile

@@ -6,7 +6,7 @@ GNU := $(ARCH)-linux-gnu
 GDB := $(GNU)-gdb
 
 QEMU := qemu-system-$(ARCH)
-QEMUFLAGS += -M raspi3b -display none -serial null
+QEMUFLAGS += -M raspi3b -display gtk -serial null
 
 CC := $(GNU)-gcc
 CCFLAGS += -Wall -Wextra -O0 \

include/logger.h

@@ -47,6 +47,22 @@ static inline char *_logger_int(char *dest, int x)
   *dest = '\0';
   return dest;
 }
+static inline char *_logger_uint(char *dest, size_t x)
+{
+  char arr[12], *c = &arr[11];
+  arr[11] = '\0';
+
+  if (x == 0)
+    *dest++ = '0';
+
+  while (x > 0)
+    *--c = x % 10 + '0', x /= 10;
+
+  for (int i = 0; c[i] != '\0'; ++i)
+    *dest++ = c[i];
+  *dest = '\0';
+  return dest;
+}
 static inline char *_logger_pointer(char *dest, void *x)
 {
   *dest++ = '*';
@@ -71,6 +87,7 @@ logger_cur = _Generic((msg), \
   const char *: _logger_string, \
   uint64_t    : _logger_hex, \
   int32_t     : _logger_int, \
+  size_t      : _logger_uint, \
   default     : _logger_pointer \
 )(logger_cur, msg)
 
@@ -80,7 +97,18 @@ logger_cur = _Generic((msg), \
   _I_HATE_C_LANG(val); \
 }
 
+static inline
+uint64_t _r_sp()
+{
+  uint64_t ret;
+  asm volatile("mov %[a], sp" : [a] "=r" (ret));
+  return ret;
+}
+
 #define FLUSH(prefix) { \
+  _logger_hex(sp_cur, _r_sp()); \
+  _uart_puts_sync(sp_buf); \
+  _uart_puts_sync(" | "); \
   _uart_puts_sync(prefix); \
   _uart_puts_sync(logger_buf); \
   _uart_puts_sync(ENDL); \
@@ -130,7 +158,10 @@ logger_cur = _Generic((msg), \
 // #define DEBUG_INITRD(val) DEBUG(val)
 #define DEBUG_INITRD(val) CLEAN
 
-#define DEBUG_THREAD(val) DEBUG(val)
+// #define DEBUG_THREAD(val) DEBUG(val)
+#define DEBUG_THREAD(val) CLEAN
 
 extern char logger_buf[LOGGER_BUFLEN];
 extern char *logger_cur;
+extern char sp_buf[LOGGER_BUFLEN];
+extern char *sp_cur;

kernel/include/exception.h

@@ -1,5 +1,10 @@
 #pragma once
 
-void init_exception(void);
+#include <stddef.h>
+#include <process.h>
+
+void exception_vector_table(void);
+
+void exception_init(void);
 void not_implemented_handler(void);
-void synchronous_handler(void);
+void synchronous_handler(trapframe_t *regs);

kernel/include/exec.h

@@ -1,3 +1,5 @@
 #pragma once
 
-void user_exec(void *text, void *sp);
+#include <process.h>
+
+void user_exec(trapframe_t *regs);

kernel/include/initrd.h

@@ -45,7 +45,7 @@ typedef struct file_node {
 
 typedef void (*initrd_callback_func_t)(file_node_t *);
 
-file_node_t *initrd_init(void);
+void initrd_init(void);
 void initrd_fdt_callback(const vector_t *props);
 file_node_t *initrd_get(file_node_t *root, const char *filename);
 void initrd_traverse(file_node_t *tr, initrd_callback_func_t func);
@@ -53,3 +53,4 @@ void initrd_traverse(file_node_t *tr, initrd_callback_func_t func);
 extern fdt_callback_t initrd_dtb_cb;
 extern void *initrd_start;
 extern void *initrd_end;
+extern file_node_t *initrd_root;

kernel/include/interrupt.h

@@ -22,7 +22,6 @@ void add_interrupt_task(uint64_t priority,
                         interrupt_callback_func_t func,
                         uint64_t param);
 
-void init_interrupt(void);
 void irq_handler(void);
 
 void wfe(void);

kernel/include/mbox.h

@@ -24,7 +24,7 @@
  */
 
 /* a properly aligned buffer */
-extern volatile unsigned int mbox[36];
+// extern volatile unsigned int mbox[36];
 
 #define MBOX_REQUEST    0
 
@@ -45,7 +45,7 @@ extern volatile unsigned int mbox[36];
 #define MBOX_TAG_GETSERIAL      0x00010004
 #define MBOX_TAG_ARM_MEMORY     0x00010005
 
-int mbox_call(unsigned char ch);
+int mbox_call(unsigned char ch, unsigned int *mbox);
 unsigned int get_board_revision(void);
 unsigned int get_memory_base_addr(void);
 unsigned int get_memory_size(void);

kernel/include/process.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <stddef.h>
+
+typedef struct {
+  uint64_t x0, x1;
+  uint64_t x2, x3;
+  uint64_t x4, x5;
+  uint64_t x6, x7;
+  uint64_t x8, x9;
+  uint64_t x10, x11;
+  uint64_t x12, x13;
+  uint64_t x14, x15;
+  uint64_t x16, x17;
+  uint64_t x18, x19;
+  uint64_t x20, x21;
+  uint64_t x22, x23;
+  uint64_t x24, x25;
+  uint64_t x26, x27;
+  uint64_t x28, fp;
+  uint64_t lr, spsr_el1;
+  uint64_t elr_el1;
+  uint64_t esr_el1;
+  uint64_t sp_el0;
+} trapframe_t;
+
+struct thread;
+
+typedef struct process {
+  int32_t pid;
+  struct thread *th;
+
+  int32_t exitcode;
+
+  void *stack;
+  size_t stack_size;
+
+  void *mem;
+  size_t mem_size;
+
+  trapframe_t *regs;
+} process_t;
+
+// thread_func_t, cast from
+// void run_process_by_name(const char *filename)
+int32_t run_process_by_name(uint64_t filename);
+
+// void run_process(process_t *)
+int32_t run_process(uint64_t process);
+
+process_t *fork_process(const process_t *from);
+
+extern int32_t global_pid_counter;

kernel/include/shell.h

@@ -1,7 +0,0 @@
-#pragma once
-
-#include <stddef.h>
-#include <initrd.h>
-
-int // is continue
-shell(file_node_t *);

kernel/include/syscall.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stddef.h>
+#include <process.h>
+
+void syscall_handler(trapframe_t *regs);
+
+int32_t sys_getpid(void);
+size_t sys_uart_read(char buf[], size_t size);
+size_t sys_uart_write(const char buf[], size_t size);
+int32_t sys_exec(const char *name, char *const argv[]);
+int32_t sys_fork(void);
+void sys_exit(int32_t status);
+int32_t sys_mbox_call(uint8_t ch, uint32_t *mbox);
+void sys_kill(int32_t pid);

kernel/include/thread.h

@@ -2,6 +2,7 @@
 
 #include <stddef.h>
 #include <queue.h>
+#include <process.h>
 
 typedef int32_t (*thread_func_t)(uint64_t);
 
@@ -20,21 +21,21 @@ typedef struct {
   uint64_t x27, x28;
   uint64_t fp, lr;
   uint64_t sp;
-  uint64_t sp_el0;
-  uint64_t elr_el1;
 } cpu_state_t;
 
-typedef struct {
+typedef struct thread {
   thread_func_t func;
   uint64_t param;
 
   thread_status_t status;
   int32_t retcode;
 
-  void *stack_pointer;
+  void *stack;
   size_t stack_size;
 
-  cpu_state_t regs;
+  cpu_state_t *regs;
+
+  process_t *process;
 } thread_t;
 
 // thread.S

kernel/include/timer.h

@@ -7,7 +7,6 @@ typedef void (*task_callback_func_t)(uint64_t);
 typedef struct {
   uint64_t firing_tick;
   uint64_t interval;
-  uint64_t repeat;
 
   task_callback_func_t func;
   uint64_t param;
@@ -20,6 +19,8 @@ typedef struct timer {
   task_t data;
 } timer_t;
 
+void timer_init(void);
+
 void add_timer_task(task_t task);
 void sleep(uint64_t ms);
 

kernel/include/utils.h

@@ -22,7 +22,7 @@ int isspace(int);
 int32_t atoi32(const char *);
 uint32_t atoh32(const char *);
 
-void exit(int);
+void panic(int errno);
 
 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
 #define MAX(x, y) (((x) < (y)) ? (y) : (x))

kernel/lib/dtb.c

@@ -85,7 +85,7 @@ void _struct_traverse(const char *path, const vector_t *cbs)
     case FDT_END:
       return;
     default:
-      exit(ERR_UNREACHABLE);
+      panic(ERR_UNREACHABLE);
     }
   }
 traverse_struct_callback:

kernel/lib/exception.S

@@ -2,7 +2,7 @@
 
 // save general registers to stack
 .macro save_all
-	sub sp, sp, 34 * 8
+	sub sp, sp, 36 * 8
 	stp x0, x1,   [sp, 16 * 0]
 	stp x2, x3,   [sp, 16 * 1]
 	stp x4, x5,   [sp, 16 * 2]
@@ -17,22 +17,26 @@
 	stp x22, x23, [sp, 16 * 11]
 	stp x24, x25, [sp, 16 * 12]
 	stp x26, x27, [sp, 16 * 13]
-	stp x28, x29, [sp, 16 * 14]
+	stp x28, fp,  [sp, 16 * 14]
 
   mrs x0, spsr_el1
   mrs x1, elr_el1
   mrs x2, esr_el1
-  stp x0, x1,   [sp, 16 * 15]
+  mrs x3, sp_el0
-  stp x2, lr,   [sp, 16 * 16]
+  stp lr, x0,   [sp, 16 * 15]
+  stp x1, x2,   [sp, 16 * 16]
+  str x3,       [sp, 16 * 17]
 .endm
 
 // load general registers from stack
 .macro load_all
-  ldp x0, x1,   [sp, 16 * 15]
+  ldp lr, x0,   [sp, 16 * 15]
-  ldp x2, lr,   [sp, 16 * 16]
+  ldp x1, x2,   [sp, 16 * 16]
+  ldr x3,       [sp, 16 * 17]
   msr spsr_el1, x0
   msr elr_el1,  x1
   msr esr_el1,  x2
+  msr sp_el0,   x3
 
 	ldp x0, x1,   [sp, 16 * 0]
 	ldp x2, x3,   [sp, 16 * 1]
@@ -48,9 +52,9 @@
 	ldp x22, x23, [sp, 16 * 11]
 	ldp x24, x25, [sp, 16 * 12]
 	ldp x26, x27, [sp, 16 * 13]
-	ldp x28, x29, [sp, 16 * 14]
+	ldp x28, fp,  [sp, 16 * 14]
 
-	add sp, sp, 34 * 8
+	add sp, sp, 36 * 8
 .endm
 
 _null_handler:
@@ -61,6 +65,7 @@ _null_handler:
 
 _synchronous_handler:
   save_all
+  mov x0, sp
   bl synchronous_handler
   load_all
   eret

kernel/lib/exception.c

@@ -3,8 +3,10 @@
 #include <stddef.h>
 #include <logger.h>
 #include <utils.h>
+#include <syscall.h>
+#include <interrupt.h>
 
-void init_exception()
+void exception_init()
 {
   asm volatile(
     "adr x0, exception_vector_table" ENDL
@@ -18,11 +20,10 @@ void not_implemented_handler()
   DEBUG_EXCEP("not implemented caught");
 }
 
-void synchronous_handler()
+void synchronous_handler(trapframe_t *regs)
 {
-  static int poop = 0;
+  disable_interrupt();
-  if (poop++ > 10)
+
-    exit(ERR_ADMINKILL);
   DEBUG_EXCEP("synchronous caught");
   uint64_t x0 = 0x0;
   R_REG(x0, x0);
@@ -36,5 +37,12 @@ void synchronous_handler()
   uint64_t esr_el1 = 0x0;
   R_SYSREG(esr_el1, esr_el1);
 
-  LOG(x0); LOG(spsr_el1); LOG(elr_el1); DEBUG_EXCEP(esr_el1);
+  LOG(x0); LOG(spsr_el1); LOG(elr_el1); DEBUG_EXCEP(esr_el1)
+
+  switch ((esr_el1 >> 26) & 0x7f) {
+  case 0b010101:
+    syscall_handler(regs);
+    break;
+  default:
+  }
 }

kernel/lib/exec.S

@@ -0,0 +1,36 @@
+.global user_exec
+user_exec:
+	
+	sub sp, sp, 36 * 8
+	mov x1, x0
+	mov x0, sp
+	mov x2, 36 * 8
+	bl memcpy
+
+	ldp lr, x0,   [sp, 16 * 15]
+	ldp x1, x2,   [sp, 16 * 16]
+	ldr x3,       [sp, 16 * 17]
+	msr spsr_el1, x0
+	msr elr_el1,  x1
+	msr esr_el1,  x2
+	msr sp_el0,   x3
+
+	ldp x0, x1,   [sp, 16 * 0]
+	ldp x2, x3,   [sp, 16 * 1]
+	ldp x4, x5,   [sp, 16 * 2]
+	ldp x6, x7,   [sp, 16 * 3]
+	ldp x8, x9,   [sp, 16 * 4]
+	ldp x10, x11, [sp, 16 * 5]
+	ldp x12, x13, [sp, 16 * 6]
+	ldp x14, x15, [sp, 16 * 7]
+	ldp x16, x17, [sp, 16 * 8]
+	ldp x18, x19, [sp, 16 * 9]
+	ldp x20, x21, [sp, 16 * 10]
+	ldp x22, x23, [sp, 16 * 11]
+	ldp x24, x25, [sp, 16 * 12]
+	ldp x26, x27, [sp, 16 * 13]
+	ldp x28, fp,  [sp, 16 * 14]
+
+	add sp, sp, 36 * 8
+
+	eret

kernel/lib/exec.c

@@ -1,16 +0,0 @@
-#include <exec.h>
-#include <utils.h>
-
-void user_exec(void *text, void *sp)
-{
-  // enable core timer
-  uint64_t cntkctl_el1 = 0x0;
-  R_SYSREG(cntkctl_el1, cntkctl_el1);
-  W_SYSREG(cntkctl_el1, cntkctl_el1 | 1);
-  W_SYSREG(cntp_ctl_el0, 1);
-  
-  W_SYSREG(spsr_el1, 0);
-  W_SYSREG(elr_el1, text);
-  W_SYSREG(sp_el0, sp);
-  asm volatile("eret");
-}

kernel/lib/initrd.c

@@ -17,6 +17,8 @@ fdt_callback_t initrd_dtb_cb = {
 void *initrd_start = 0x0;
 void *initrd_end   = 0x0;
 
+file_node_t *initrd_root = 0x0;
+
 void initrd_fdt_callback(const vector_t *props)
 {
   for (int i = 0; i < (int)props->size; ++i) {
@@ -87,7 +89,7 @@ static inline void _split(file_node_t *rt, const char *s,
 
 cpio_newc_header_t *initrd_cur;
 
-file_node_t *initrd_init(void)
+void initrd_init(void)
 {
   cpio_newc_header_t *header;
   char *filename;
@@ -128,8 +130,8 @@ file_node_t *initrd_init(void)
     _split(root, filename, &ltr, &rtr);
     root = _merge(ltr, _merge(newnode, rtr));
   }
-  
+
-  return root;
+  initrd_root = root;
 }
 
 static inline file_node_t *_node_bs(file_node_t *cur, const char *s)

kernel/lib/interrupt.c

@@ -91,19 +91,11 @@ void add_interrupt_task(uint64_t priority,
   }
 }
 
-void init_interrupt(void)
-{
-  enable_interrupt();
-  _enable_timer_irq(true);
-}
-
 void irq_handler(void)
 {
   // uint64_t core0_irq_source = *CORE0_IRQ_SOURCE;
   // DEBUG_EXCEP(core0_irq_source);
 
-  // TODO: turnoff global interrupt
-
   if (_irq_source_timer())
     timer_irq_handler();
 

kernel/lib/kmalloc.c

@@ -37,7 +37,7 @@ void *simple_alloc(size_t size)
   size = (size_t)ALIGN8(size);
   
   if ((uint64_t)_heap_top + size >= (uint64_t)&__heap_end)
-    exit(ERR_NO_MEM);
+    panic(ERR_NO_MEM);
 
   void *ret = _heap_top;
   _heap_top = (void *)((uint64_t)_heap_top + size);
@@ -49,17 +49,19 @@ void *simple_alloc(size_t size)
 
 void *mman_alloc(size_t unit)
 {
+  LOG("mman_alloc called"); DEBUG_MEM(unit);
   unit = (size_t)ALIGN8(unit);
   if (unit > (KMALLOC_MAX_ALLOCATOR_SIZE << 3))
     return allocate_page(((unit - 1) >> 12) + 1);
 
   kmalloc_allocator_t *pool = &mman_kmalloc_pool[unit >> 3];
-  if (!pool->left) {
+  if (!pool->page_begin || !pool->left) {
-    void *page = allocate_page(1), *ptr = page + sizeof(kmalloc_header_t);
+    void *page = allocate_page(1);
+
     *(kmalloc_header_t *)page = (kmalloc_header_t){
       .unit = unit,
       .left = (PAGE_SIZE - sizeof(kmalloc_header_t)) / unit,
-      .begin = page + sizeof(kmalloc_header_t),
+      .begin = (void *)((uint64_t)page + sizeof(kmalloc_header_t)),
       .page_prev = (kmalloc_header_t *)0x0,
       .page_next = (kmalloc_header_t *)0x0,
     };
@@ -67,20 +69,31 @@ void *mman_alloc(size_t unit)
       .left = ((kmalloc_header_t *)page)->left,
       .page_begin = (kmalloc_header_t *)page,
     };
+    LOG(page); LOG(sizeof(kmalloc_header_t)); DEBUG_MEM(pool->page_begin->begin);
 
-    for (; ptr + unit <= page + PAGE_SIZE; ptr += unit)
+    uint64_t ptr = (uint64_t)page + sizeof(kmalloc_header_t);
-      *(void **)ptr = ptr + unit;
+    for (; ptr + unit <= (uint64_t)page + PAGE_SIZE; ptr += unit)
+      *(uint64_t *)ptr = ptr + unit;
   }
 
   void *ret = pool->page_begin->begin;
+  LOG(pool); LOG(pool->page_begin); DEBUG_MEM(pool->left);
+  LOG(pool->page_begin->left); DEBUG_MEM(pool->page_begin->begin);
   pool->page_begin->begin = *(void **)pool->page_begin->begin;
   
-  --pool->left;
+  pool->left--;
-  --pool->page_begin->left;
+  pool->page_begin->left--;
-  if (!pool->page_begin->left)
+  if (!pool->left)
-    pool->page_begin = *(void **)pool->page_begin->page_next;
+    pool->page_begin = 0x0;
+  while (pool->page_begin && !pool->page_begin->left) {
+    pool->page_begin = pool->page_begin->page_next;
+    if (pool->page_begin)
+      pool->page_begin->page_prev = 0x0;
+  }
 
   LOG("mman_alloc"); LOG((uint64_t)unit); DEBUG_MEM(ret);
+  LOG(pool->page_begin); LOG(pool->page_begin->left);
+  DEBUG_MEM(pool->page_begin->begin);
   return ret;
 }
 
@@ -91,6 +104,8 @@ void mman_free(void *ptr)
     return;
   }
 
+  return; // early return for debugging
+
   size_t unit = PAGE_HEADER(ptr)->unit;
   kmalloc_allocator_t *pool = &mman_kmalloc_pool[unit >> 3];
   if (!PAGE_HEADER(ptr)->left) {

kernel/lib/mbox.c

@@ -27,7 +27,7 @@
 #include <mbox.h>
 
 /* mailbox message buffer */
-volatile unsigned int  __attribute__((aligned(16))) mbox[36];
+// volatile unsigned int  __attribute__((aligned(16))) mbox[36];
 
 #define VIDEOCORE_MBOX  (MMIO_BASE+0x0000B880)
 #define MBOX_READ       ((volatile unsigned int*)(VIDEOCORE_MBOX+0x0))
@@ -49,7 +49,7 @@ volatile unsigned int  __attribute__((aligned(16))) mbox[36];
 /**
  * Make a mailbox call. Returns 0 on failure, non-zero on success
  */
-int mbox_call(unsigned char ch)
+int mbox_call(unsigned char ch, unsigned int *mbox)
 {
   unsigned int r = (((unsigned int)((unsigned long)&mbox)&~0xF) | (ch&0xF));
   /* wait until we can write to the mailbox */
@@ -57,7 +57,7 @@ int mbox_call(unsigned char ch)
   /* write the address of our message to the mailbox with channel identifier */
   *MBOX_WRITE = r;
   /* now wait for the response */
-  while(1) {
+  for (;;) {
     /* is there a response? */
     do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_EMPTY);
     /* is it a response to our message? */
@@ -70,6 +70,7 @@ int mbox_call(unsigned char ch)
 
 unsigned int get_board_revision(void)
 {
+  unsigned int  __attribute__((aligned(16))) mbox[36];
   mbox[0] = 36 * 4;
   mbox[1] = MBOX_REQUEST;
 
@@ -81,13 +82,14 @@ unsigned int get_board_revision(void)
 
   mbox[6] = MBOX_TAG_LAST;
 
-  mbox_call(MBOX_CH_PROP);
+  mbox_call(MBOX_CH_PROP, mbox);
 
   return mbox[5];
 }
 
 unsigned int get_memory_base_addr(void)
 {
+  unsigned int  __attribute__((aligned(16))) mbox[36];
   mbox[0] = 36 * 4;
   mbox[1] = MBOX_REQUEST;
 
@@ -100,13 +102,14 @@ unsigned int get_memory_base_addr(void)
 
   mbox[7] = MBOX_TAG_LAST;
 
-  mbox_call(MBOX_CH_PROP);
+  mbox_call(MBOX_CH_PROP, mbox);
 
   return mbox[5];
 }
 
 unsigned int get_memory_size(void)
 {
+  unsigned int  __attribute__((aligned(16))) mbox[36];
   mbox[0] = 36 * 4;
   mbox[1] = MBOX_REQUEST;
 
@@ -119,7 +122,7 @@ unsigned int get_memory_size(void)
 
   mbox[7] = MBOX_TAG_LAST;
 
-  mbox_call(MBOX_CH_PROP);
+  mbox_call(MBOX_CH_PROP, mbox);
 
   return mbox[6];
 }

kernel/lib/mman.c

@@ -66,7 +66,7 @@ void _pull(int idx, size_t sz)
     CUR->size = 0;
     break;
   default:
-    exit(ERR_UNREACHABLE);
+    panic(ERR_UNREACHABLE);
   }
 }
 
@@ -96,6 +96,7 @@ void mman_init()
       (void *)ntoh64(entry->address) + ntoh64(entry->size));
   }
 
+  reserve_page((void *)0x00000000, (void *)0x00001000);
   reserve_page(&__kernel_start, &__kernel_end);
   reserve_page(&__heap_start, &__stack_end);
   reserve_page(dtb_start, dtb_end);
@@ -132,7 +133,7 @@ uint64_t _allocate_page(size_t req, int idx, uint64_t l, uint64_t r)
   case PAGE_RESERVED:
     return MMAN_NO_PAGE;
   default:
-    exit(ERR_UNREACHABLE);
+    panic(ERR_UNREACHABLE);
   }
 
   uint64_t ret = MMAN_NO_PAGE;
@@ -162,12 +163,12 @@ uint64_t _allocate_page(size_t req, int idx, uint64_t l, uint64_t r)
 void *allocate_page(size_t page_cnt)
 {
   if (msb64(page_cnt) != page_cnt)
-    exit(ERR_INVALID_OP);
+    panic(ERR_INVALID_OP);
 
   uint64_t offset = _allocate_page(page_cnt, 0, 0, mman_page_cnt);
   
   if (offset == MMAN_NO_PAGE)
-    exit(ERR_NO_MEM);
+    panic(ERR_NO_MEM);
     // return (void *)0x0;
 
   return mman_memory_start + offset * (1 << 12);
@@ -192,7 +193,7 @@ void _free_page(uint64_t req, int idx, uint64_t l, uint64_t r)
     break;
   case PAGE_RESERVED:
   default:
-    exit(ERR_UNREACHABLE);
+    panic(ERR_UNREACHABLE);
   }
 
   uint64_t m = l + ((msb64(sz) == sz) ? (sz >> 1) : msb64(sz));
@@ -206,7 +207,7 @@ void _free_page(uint64_t req, int idx, uint64_t l, uint64_t r)
 void free_page(void *page)
 {
   if (ALIGN4K(page) != page)
-    exit(ERR_INVALID_OP);
+    panic(ERR_INVALID_OP);
 
   uint64_t start = ((uint64_t)page - (uint64_t)mman_memory_start) >> 12;
   _free_page(start, 0, 0, mman_page_cnt); 
@@ -223,7 +224,7 @@ void _reserve_page(uint64_t ql, uint64_t qr, int idx, uint64_t l, uint64_t r)
     if (CUR->state == PAGE_RESERVED)
       return;
     if (CUR->state != PAGE_FREE)
-      exit(ERR_INVALID_MEM);
+      panic(ERR_INVALID_MEM);
 
     LOG("page reserved"); LOG(l); DEBUG_MEM(r);
     CUR->state = PAGE_RESERVED;

kernel/lib/process.c

@@ -0,0 +1,113 @@
+#include <process.h>
+#include <utils.h>
+#include <errcode.h>
+#include <logger.h>
+#include <thread.h>
+#include <kmalloc.h>
+#include <mman.h>
+#include <exec.h>
+#include <initrd.h>
+#include <string.h>
+#include <interrupt.h>
+
+int32_t global_pid_counter = 0;
+
+static inline
+process_t *_make_process(const char *filename)
+{
+  process_t *ret = kmalloc(sizeof(process_t));
+
+  file_node_t *file = initrd_get(initrd_root, filename);
+  if (file == 0x0)
+    panic(ERR_NOT_EXIST);
+
+  *ret = (process_t){
+    .pid = global_pid_counter++,
+    .th = 0x0,
+
+    .exitcode = 0,
+
+    .stack = allocate_page(256),
+    .stack_size = 256 << 12,
+
+    .mem = allocate_page(256),
+    .mem_size = 256 << 12,
+
+    .regs = kmalloc(sizeof(trapframe_t)),
+  };
+  memcpy(ret->mem, file->filecontent, file->filesize);
+  memset(ret->regs, 0x0, sizeof(trapframe_t));
+  *ret->regs = (trapframe_t){
+    .spsr_el1 = 0x0, // enable all interrupt
+    .elr_el1 = (uint64_t)ret->mem,
+    .sp_el0 = ((uint64_t)ret->stack + ret->stack_size - 64),
+  };
+
+  return ret;
+}
+
+// void run_process_by_name(const char *filename)
+int32_t run_process_by_name(uint64_t param)
+{
+  const char *filename = (void *)param;
+  thread_t *th = get_current();
+
+  th->process = _make_process(filename);
+  th->process->th = th;
+  LOG("Run process by name"); DEBUG_THREAD(filename);
+  LOG(th->process->stack); DEBUG_THREAD(th->process->regs->sp_el0);
+  LOG(th->process->mem); DEBUG_THREAD(th->process->regs->elr_el1);
+
+  disable_interrupt();
+  user_exec(th->process->regs);
+
+  __builtin_unreachable();
+  return 0;
+}
+
+// void run_process(process_t *)
+int32_t run_process(uint64_t param)
+{
+  process_t *process = (void *)param;
+  thread_t *th = get_current();
+
+  th->process = process;
+  th->process->th = th;
+  LOG("Run process"); DEBUG_THREAD(process->pid);
+
+  disable_interrupt();
+  user_exec(th->process->regs);
+
+  __builtin_unreachable();
+  return 0;
+}
+
+process_t *fork_process(const process_t *from)
+{
+  process_t *ret = kmalloc(sizeof(process_t));
+  *ret = (process_t){
+    .pid = global_pid_counter++,
+    .th = 0x0,
+
+    .exitcode = from->exitcode,
+
+    .stack = allocate_page(256),
+    .stack_size = 256 << 12,
+
+    .mem = allocate_page(256),
+    .mem_size = 256 << 12,
+
+    .regs = kmalloc(sizeof(trapframe_t)),
+  };
+  memcpy(ret->stack, from->stack, from->stack_size);
+  memcpy(ret->mem, from->mem, from->mem_size);
+  *ret->regs = (trapframe_t){
+    .x0 = 0, // fork return value
+    .fp = from->regs->fp - (uint64_t)from->stack + (uint64_t)ret->stack,
+    .lr = from->regs->lr - (uint64_t)from->mem + (uint64_t)ret->mem,
+    .sp_el0 = from->regs->sp_el0 - (uint64_t)from->stack + (uint64_t)ret->stack,
+    .elr_el1 = from->regs->elr_el1 - (uint64_t)from->mem + (uint64_t)ret->mem,
+  };
+
+  return ret;
+}

kernel/lib/queue.c

@@ -23,14 +23,14 @@ queue_t *make_queue()
 uint64_t queue_back(const queue_t *queue)
 {
   if (!queue->size)
-    exit(ERR_OUT_OF_BOUND);
+    panic(ERR_OUT_OF_BOUND);
   return queue->end->prev->value;
 }
 
 uint64_t queue_front(const queue_t *queue)
 {
   if (!queue->size)
-    exit(ERR_OUT_OF_BOUND);
+    panic(ERR_OUT_OF_BOUND);
   return queue->begin->next->value;
 }
 
@@ -63,7 +63,7 @@ void queue_push_front(queue_t *queue, uint64_t val)
 uint64_t queue_pop_back(queue_t *queue)
 {
   if (!queue->size)
-    exit(ERR_OUT_OF_BOUND);
+    panic(ERR_OUT_OF_BOUND);
 
   uint64_t ret = queue->end->prev->value;
   queue->end->prev = queue->end->prev->prev;
@@ -76,7 +76,7 @@ uint64_t queue_pop_back(queue_t *queue)
 uint64_t queue_pop_front(queue_t *queue)
 {
   if (!queue->size)
-    exit(ERR_OUT_OF_BOUND);
+    panic(ERR_OUT_OF_BOUND);
 
   uint64_t ret = queue->begin->next->value;
   queue->begin->next = queue->begin->next->next;

kernel/lib/ringbuffer.c

@@ -35,7 +35,7 @@ int ringbuffer_push(ringbuffer_t *buf, uint8_t val)
 uint8_t ringbuffer_bump(ringbuffer_t *buf)
 {
   if (buf->size == 0)
-    exit(ERR_INVALID_OP);
+    panic(ERR_INVALID_OP);
 
   uint8_t ret = *buf->read++;
 
@@ -49,7 +49,7 @@ uint8_t ringbuffer_bump(ringbuffer_t *buf)
 uint8_t ringbuffer_peek(ringbuffer_t *buf)
 {
   if (buf->size == 0)
-    exit(ERR_INVALID_OP);
+    panic(ERR_INVALID_OP);
 
   return *buf->read;
 }

kernel/lib/shell.c

@@ -1,256 +0,0 @@
-#include <stddef.h>
-#include <logger.h>
-#include <timer.h>
-#include <errcode.h>
-#include <kmalloc.h>
-#include <utils.h>
-#include <string.h>
-#include <uart.h>
-#include <mbox.h>
-#include <shell.h>
-#include <exec.h>
-#include <mman.h>
-
-#define INPUT_BUFLEN 1000
-
-#define PM_PASSWORD 0x5a000000
-
-#define PM_RSTC 0x3F10001c
-#define PM_WDOG 0x3F100024
-
-static inline
-void _help (void)
-{
-  uart_puts(
-    "help                         : print this help menu" ENDL
-    "hello                        : print Hello World!" ENDL
-    "hwinfo                       : print hardware info" ENDL
-    "memalloc   <size>            : alloate memory and print" ENDL
-    "ls                           : list directory contents" ENDL
-    "cat        <file>            : concatenate files and print" ENDL
-    "exec       <file>            : execute file in usermode" ENDL
-    "settimeout <sec> <message...>: pring message after a few seconds" ENDL
-    "time                         : print current time tick" ENDL
-    "reboot                       : reboot the device" ENDL
-  );
-}
-
-static inline
-void _hello (void)
-{
-  uart_puts("hello, world" ENDL);
-}
-
-static inline
-void _hwinfo (void)
-{
-  uart_puts(
-    "hwinfo: " ENDL
-    "board revision: "
-  );
-  uart_hex(get_board_revision());
-  uart_puts(
-    ENDL
-    "memory base addr: "
-  );
-  uart_hex(get_memory_base_addr());
-  uart_puts(
-    ENDL
-    "memory size: "
-  );
-  uart_hex(get_memory_size());
-  uart_puts(ENDL);
-}
-
-static inline
-void _memalloc(size_t size)
-{
-  void *addr = kmalloc(size);
-  uart_puts("size: ");
-  uart_hex(size);
-  uart_puts(ENDL);
-
-  uart_puts("addr: ");
-  uart_hex((uint64_t)addr);
-  uart_puts(ENDL);
-}
-
-static inline
-void _free(uint64_t ptr)
-{
-  kfree((void *)ptr);
-  LOG(ptr); INFOR("has been freed");
-}
-
-static inline
-void _ls_initrd_callback(file_node_t *tr)
-{
-  uart_puts(tr->filename);
-  uart_puts(ENDL);
-}
-
-static inline
-void _ls(file_node_t *root)
-{
-  initrd_traverse(root, _ls_initrd_callback);
-}
-
-static inline
-void _cat(file_node_t *root, const char *filename)
-{
-  file_node_t *tr = initrd_get(root, filename);
-  if (tr) {
-    uart_puts((char *)tr->filecontent);
-  } else {
-    exit(ERR_NOT_EXIST);
-  }
-}
-
-static inline
-void _exec(file_node_t *root, const char *filename)
-{
-  file_node_t *tr = initrd_get(root, filename);
-  if (tr) {
-    void *userspace = allocate_page(1 << 6);
-    memcpy(userspace, tr->filecontent, tr->filesize);
-    user_exec(userspace, userspace + (1 << (12 + 6)) - 8);
-    kfree(userspace);
-  } else {
-    exit(ERR_NOT_EXIST);
-  }
-}
-
-static inline
-void _settimeout_cb_func(uint64_t args)
-{
-  vector_t *v = (void *)args;
-  uart_puts("timeout: ");
-  for (int i = 2; i < (int)v->size; ++i) {
-    uart_puts(VEC_AT(char, v, i));
-    uart_puts(" ");
-  }
-  uart_puts(ENDL);
-}
-
-static inline
-void _settimeout(int32_t sec, vector_t *args)
-{
-  uint64_t cntpct_el0, cntfrq_el0;
-  R_SYSREG(cntpct_el0, cntpct_el0);
-  R_SYSREG(cntfrq_el0, cntfrq_el0);
-
-  task_t task = (task_t){
-    .firing_tick = cntpct_el0 + sec * cntfrq_el0,
-    .interval = sec * cntfrq_el0,
-    .repeat = 1,
-
-    .func = _settimeout_cb_func,
-    .param = (uint64_t)args,
-  };
-  add_timer_task(task);
-}
-
-static inline
-void _time()
-{
-  uint64_t cntpct_el0, cntfrq_el0, cntp_cval_el0, cntp_tval_el0;
-  R_SYSREG(cntpct_el0, cntpct_el0);
-  R_SYSREG(cntfrq_el0, cntfrq_el0);
-  R_SYSREG(cntp_cval_el0, cntp_cval_el0);
-  R_SYSREG(cntp_tval_el0, cntp_tval_el0);
-
-  LOG(cntpct_el0); LOG(cntfrq_el0); LOG(cntp_cval_el0); INFOR(cntp_tval_el0);
-}
-
-static inline
-void _set(long addr, unsigned int value) {
-  volatile unsigned int* point = (unsigned int*)addr;
-  *point = value;
-}
-
-static inline
-void _reset(int tick) {               // reboot after watchdog timer expire
-  _set(PM_RSTC, PM_PASSWORD | 0x20);  // full reset
-  _set(PM_WDOG, PM_PASSWORD | tick);  // number of watchdog tick
-}
-
-static inline
-void _reboot(void)
-{
-  _reset(1 << 16);
-}
-
-char *_shell_buf = (char *)0x0;
-int _shell_sz = 0;
-
-static inline
-int _shell_operations(char ch)
-{
-  switch (ch) {
-  case 0x7f:
-    if (_shell_sz > 0) {
-      --_shell_sz;
-      uart_puts("\b \b");
-    }
-    return true;
-  default:
-  }
-  return false;
-}
-
-int shell(file_node_t *initrd_root)
-{
-  uart_puts("# ");
-  char ch;
-  _shell_buf = kmalloc(INPUT_BUFLEN * sizeof(char));
-  _shell_sz = 0;
-  while ((ch = uart_getc()) != '\n') {
-    if (_shell_operations(ch))
-      continue;
-    _shell_buf[_shell_sz++] = ch;
-    uart_putb((const uint8_t *)&ch, 1);
-  }
-  uart_puts(ENDL);
-  _shell_buf[_shell_sz] = ' ';
-
-  vector_t *args = make_vector(0);
-  for (char *saveptr = 0x0, *tok = strtok_r(_shell_buf, " ", &saveptr);
-       tok; tok = strtok_r((char *)0x0, " ", &saveptr)) {
-    VEC_PUSH(args, tok);
-    LOG(tok);
-  }
-  // DEBUG("ENDL");
-  CLEAN;
-
-  char *cmd = args->size ? VEC_AT(char, args, 0) : (char *)0x0;
-  if (!strcmp(cmd, "help")) {
-    _help();
-  } else if (!strcmp(cmd, "hello")) {
-    _hello();
-  } else if (!strcmp(cmd, "hwinfo")) {
-    _hwinfo();
-  } else if (!strcmp(cmd, "memalloc") && args->size >= 2) {
-    char *p1 = VEC_AT(char, args, 1);
-    _memalloc((size_t)atoi32(p1));
-  } else if (!strcmp(cmd, "free") && args->size >= 2) {
-    char *p1 = VEC_AT(char, args, 1);
-    _free((uint64_t)atoh32(p1));
-  } else if (!strcmp(cmd, "ls")) {
-    _ls(initrd_root);
-  } else if (!strcmp(cmd, "cat") && args->size >= 2) {
-    char *p1 = VEC_AT(char, args, 1);
-    _cat(initrd_root, p1);
-  } else if (!strcmp(cmd, "exec") && args->size >= 2) {
-    char *p1 = VEC_AT(char, args, 1);
-    _exec(initrd_root, p1);
-  } else if (!strcmp(cmd, "settimeout") && args->size >= 2) {
-    char *p1 = VEC_AT(char, args, 1);
-    _settimeout(atoi32(p1), args);
-  } else if (!strcmp(cmd, "time")) {
-    _time();
-  } else if (!strcmp(cmd, "reboot")) {
-    _reboot();
-  }
-  
-  return true;
-}

kernel/lib/syscall.c

@@ -0,0 +1,79 @@
+#include <syscall.h>
+#include <logger.h>
+#include <uart.h>
+#include <thread.h>
+#include <process.h>
+#include <mbox.h>
+
+void syscall_handler(trapframe_t *regs)
+{
+  thread_t *th = get_current();
+  th->process->regs = regs;
+
+  switch (regs->x8) {
+  case 0: // int32_t getpid(void)
+    regs->x0 = sys_getpid();
+    break;
+  case 1: // size_t uart_read(char buf[], size_t size)
+    regs->x0 = sys_uart_read((char *)regs->x0, (size_t)regs->x1);
+    break;
+  case 2: // size_t uart_write(const char buf[], size_t size)
+    regs->x0 = sys_uart_write((const char *)regs->x0, (size_t)regs->x1);
+    break;
+  case 3: // int32_t exec(const char *name, char *const argv[])
+    regs->x0 = sys_exec((const char *)regs->x0, (char *const *)regs->x1);
+    break;
+  case 4: // int32_t fork(void)
+    regs->x0 = sys_fork();
+    break;
+  case 5: // void exit(int32_t status)
+    sys_exit((int)regs->x0);
+    break;
+  case 6: // int32_t mbox_call(uint8_t ch, uint32_t *mbox)
+    regs->x0 = sys_mbox_call((uint8_t)regs->x0, (uint32_t *)regs->x1);
+    break;
+  case 7: // void kill(int32_t pid)
+    sys_kill((int)regs->x0);
+    break;
+  default:
+    LOG("unsupported syscall"); ERROR(regs->x8);
+  }
+}
+
+int32_t sys_getpid(void)
+{
+  thread_t *th = get_current();
+  if (th->process == 0x0)
+    return -1;
+  return th->process->pid;
+}
+
+size_t sys_uart_read(char buf[], size_t size)
+{ return uart_getb_sync((uint8_t *)buf, size); }
+
+size_t sys_uart_write(const char buf[], size_t size)
+{ return uart_putb_sync((const uint8_t *)buf, size); }
+
+int32_t sys_exec(const char *name, char *const argv[])
+{ return run_process_by_name((uint64_t)name); /* ignore argv for now */ }
+
+int32_t sys_fork(void)
+{
+  thread_t *cur = get_current();
+  process_t *newproc = fork_process(cur->process);
+  run_thread(run_process, (uint64_t)newproc);
+  return newproc->pid;
+}
+
+void sys_exit(int32_t status)
+{
+  thread_t *th = get_current();
+  th->status = THREAD_STATUS_ZOMBIE;
+}
+
+int32_t sys_mbox_call(uint8_t ch, uint32_t *mbox)
+{ return mbox_call(ch, mbox); }
+
+void sys_kill(int32_t pid)
+{
+}

kernel/lib/thread.c

@@ -6,6 +6,7 @@
 #include <queue.h>
 #include <interrupt.h>
 #include <string.h>
+#include <timer.h>
 
 queue_t *global_run_queue = 0x0;
 queue_t *global_wait_queue = 0x0;
@@ -21,9 +22,11 @@ thread_t *get_current(void)
 static inline
 void _thread_wrapper()
 {
+  enable_interrupt();
+
   thread_t *cur = get_current();
 
-  LOG("Running"); DEBUG_THREAD(cur->func);
+  LOG("Running thread wrapper"); DEBUG_THREAD(cur->func);
   cur->func(cur->param);
 
   cur->status = THREAD_STATUS_ZOMBIE;
@@ -43,19 +46,26 @@ thread_t *_make_thread(thread_func_t func, uint64_t param)
     .status = THREAD_STATUS_RUNABLE,
     .retcode = 0,
 
-    .stack_pointer = allocate_page(256),
+    .stack = allocate_page(256),
     .stack_size = 256 << 12,
+
+    .regs = kmalloc(sizeof(cpu_state_t)),
+
+    .process = 0x0,
   };
-  memset(&ret->regs, 0, sizeof(cpu_state_t));
+  memset(ret->regs, 0, sizeof(cpu_state_t));
-  ret->regs.sp = (uint64_t)ret->stack_pointer + ret->stack_size - 64;
+  ret->regs->sp = (uint64_t)ret->stack + ret->stack_size - 64;
-  ret->regs.lr = (uint64_t)_thread_wrapper;
+  ret->regs->lr = (uint64_t)_thread_wrapper;
-  ret->regs.fp = ret->regs.sp;
+  ret->regs->fp = ret->regs->sp;
 
   return ret;
 }
 
 void run_thread(thread_func_t func, uint64_t param)
-{ QUEUE_PUSH_BACK(global_run_queue, _make_thread(func, param)); }
+{
+  // Runs before enable interrupt
+  QUEUE_PUSH_BACK(global_run_queue, _make_thread(func, param));
+}
 
 static inline
 int32_t _idle(uint64_t)
@@ -63,7 +73,9 @@ int32_t _idle(uint64_t)
   DEBUG_THREAD("enter idle thread");
 
   for (;;) {
+    enable_interrupt();
     schedule();
+    DEBUG_THREAD(global_gc_queue->size);
     // DEBUG_THREAD("back to idle thread");
   }
 
@@ -76,23 +88,20 @@ void thread_init(void)
   global_wait_queue = make_queue();
   global_gc_queue = make_queue();
 
+  thread_t *th = kmalloc(sizeof(thread_t));
+  W_SYSREG(tpidr_el1, th);
+
   run_thread(_idle, 0x0);
 }
 
 void schedule(void)
 {
-  // DEBUG_THREAD("schedule!");
   disable_interrupt();
 
-  // DEBUG_THREAD("run queue:");
+  thread_t *th = get_current(), *next = 0x0;
-  for (queue_node_t *n = global_run_queue->begin->next;
+  LOG("Run thread"); LOG(global_run_queue->size); DEBUG_THREAD(th);
-      n != global_run_queue->end;
+  LOG(th->stack); DEBUG_THREAD(th->regs->sp);
-      n = n->next) {
 
-    // LOG(n); DEBUG_THREAD(n->value);
-  }
-
-  thread_t *cur = get_current(), *next = 0x0;
   while (global_run_queue->size > 0 && !next) {
     next = QUEUE_POP_FRONT(thread_t, global_run_queue);
     if (next->status == THREAD_STATUS_ZOMBIE) {
@@ -102,8 +111,8 @@ void schedule(void)
       QUEUE_PUSH_BACK(global_run_queue, next);
   }
   
-  if (next && cur != next)
+  if (next && th != next)
-    context_switch(&cur->regs, &next->regs, next);
+    context_switch(th->regs, next->regs, next);
 
   enable_interrupt();
 }

kernel/lib/timer.c

@@ -11,6 +11,45 @@ timer_t *global_timer = (timer_t *)0x0;
 
 MMIO_W_HELPER(_enable_timer_irq, CORE0_TIMER_IRQ_CTRL, 0x1, 1);
 
+static inline
+task_t _make_timer_task(uint64_t interval_s, task_callback_func_t func,
+                        uint64_t param)
+{
+  uint64_t cntpct_el0, cntfrq_el0;
+  R_SYSREG(cntpct_el0, cntpct_el0);
+  R_SYSREG(cntfrq_el0, cntfrq_el0);
+
+  return (task_t){
+    .firing_tick = cntpct_el0 + interval_s * cntfrq_el0,
+    .interval = interval_s * cntfrq_el0,
+
+    .func = func,
+    .param = param,
+  };
+}
+
+static inline
+void _scheduler_timeout(uint64_t)
+{
+  add_timer_task(_make_timer_task(1, _scheduler_timeout, 0x0));
+  schedule();
+}
+
+void timer_init()
+{
+  uint64_t cntkctl_el1, cntfrq_el0;
+  R_SYSREG(cntkctl_el1, cntkctl_el1);
+  W_SYSREG(cntkctl_el1, cntkctl_el1 | 1);
+  W_SYSREG(cntp_ctl_el0, 1);
+  _enable_timer_irq(true);
+
+  R_SYSREG(cntfrq_el0, cntfrq_el0);
+  W_SYSREG(cntp_tval_el0, cntfrq_el0 >> 1);
+
+  return;
+  add_timer_task(_make_timer_task(1, _scheduler_timeout, 0x0));
+}
+
 static inline
 uint32_t _d(timer_t *t)
 { return t ? t->_d : 0; }
@@ -42,8 +81,10 @@ timer_t *_merge(timer_t *a, timer_t *b)
 static inline
 timer_t *_pop(timer_t *t)
 {
-  if (!t || (!t->_l && !t->_r))
+  if (!t || (!t->_l && !t->_r)) {
+    kfree(t);
     return (timer_t *)0x0;
+  }
   return _merge(t->_l, t->_r);
 }
 
@@ -126,6 +167,9 @@ void _timer_task_wrapper(uint64_t param)
 void timer_irq_handler(void)
 {
   _enable_timer_irq(false);
+  schedule();
+  _enable_timer_irq(true);
+  return;
 
   uint64_t cntpct_el0;
   R_SYSREG(cntpct_el0, cntpct_el0);

kernel/lib/uart.c

@@ -76,11 +76,13 @@ void uart_init(void)
   uart_readbuf = make_ringbuffer(UART_BUFLEN);
   uart_writebuf = make_ringbuffer(UART_BUFLEN);
 
-  _uart_enable_receive_interrupt(true);
+  // _uart_enable_receive_interrupt(true);
-  //uint64_t ier = *AUX_MU_IER;
+  _uart_enable_receive_interrupt(false);
+  _uart_enable_transmit_interrupt(false);
+  // uint64_t ier = *AUX_MU_IER;
 
-  uart_getb = uart_getb_async;
+  // uart_getb = uart_getb_async;
-  uart_putb = uart_putb_async;
+  // uart_putb = uart_putb_async;
 
   is_uart_inited = true;
 }
@@ -203,7 +205,7 @@ void uart_puts(const char *s)
   size_t len = strlen(s);
   size_t ret = uart_putb((const uint8_t *)s, len);
   if (ret != len)
-    exit(ERR_IO_FAILED);
+    panic(ERR_IO_FAILED);
 }
 
 void uart_hex(uint64_t d)

kernel/lib/utils.c

@@ -97,7 +97,7 @@ int isupper(int c)
 int32_t atoi32(const char *s)
 {
   if (!s)
-    exit(ERR_CONVERSION);
+    panic(ERR_CONVERSION);
 
   int is_neg = 0;
   if (*s != '\0' && *s == '-')
@@ -106,7 +106,7 @@ int32_t atoi32(const char *s)
   int32_t ret = 0;
   for (; *s != '\0'; ++s) {
     if (!isdigit(*s))
-      exit(ERR_CONVERSION);
+      panic(ERR_CONVERSION);
     ret *= 10, ret += *s - '0';
   }
 
@@ -116,12 +116,12 @@ int32_t atoi32(const char *s)
 uint32_t atoh32(const char *s)
 {
   if (!s)
-    exit(ERR_CONVERSION);
+    panic(ERR_CONVERSION);
 
   uint32_t ret = 0;
   for (int i = 8; i-- && *s != '\0'; ++s) {
     if (!isxdigit(*s))
-      exit(ERR_CONVERSION);
+      panic(ERR_CONVERSION);
     ret <<= 4, ret |= (isdigit(*s) ? *s - '0' : 
                       (isupper(*s) ? *s - 'A' + 10 : 
                                      *s - 'a' + 10));
@@ -130,7 +130,7 @@ uint32_t atoh32(const char *s)
   return ret;
 }
 
-void exit(int exit_code)
+void panic(int exitcode)
 {
   static int print = 0;
   if (!print) {
@@ -138,14 +138,14 @@ void exit(int exit_code)
       "OOPS! YOUR KERNEL DEAD" ENDL
       "ERROR CODE: "
     );
-    uart_hex(exit_code);
+    uart_hex(exitcode);
     uart_puts(ENDL);
     print = 1;
   }
 
   asm volatile(
     "wfe\n"
-    "b exit"
+    "b panic"
   );
   __builtin_unreachable();
 }

kernel/lib/vector.c

@@ -21,7 +21,7 @@ vector_t *make_vector(size_t size)
 uint64_t vec_at(const vector_t *vec, size_t idx)
 {
   if (idx >= vec->size)
-    exit(ERR_OUT_OF_BOUND);
+    panic(ERR_OUT_OF_BOUND);
   
   return vec->data[idx];
 }

kernel/main.c

@@ -1,23 +1,22 @@
 #include <logger.h>
-#include <timer.h>
+#include <process.h>
+#include <thread.h>
 #include <kmalloc.h>
 #include <uart.h>
 #include <dtb.h>
 #include <initrd.h>
 #include <mman.h>
-#include <shell.h>
 #include <vector.h>
 #include <utils.h>
-#include <thread.h>
+#include <timer.h>
 #include <exception.h>
 #include <interrupt.h>
 
 static inline
-void _init(void *dtb, file_node_t **initrd_root)
+void _init(void *dtb)
 {
-  init_exception();
+  exception_init();
 
-  // UART
   uart_init();
 
   // Device tree
@@ -29,56 +28,22 @@ void _init(void *dtb, file_node_t **initrd_root)
   fdt_traverse(dtb_struct_cbs);
   DEBUG_DTB("device tree parse done");
 
-  // Initramfs
+  initrd_init();
-  DEBUG_INITRD(initrd_start);
-  *initrd_root = initrd_init();
 
-  // Memory (Buddy system)
   mman_init();
 
-  // Threads
   thread_init();
   
-  init_interrupt();
+  timer_init();
-}
 
-static inline
+  enable_interrupt();
-void _print_time(uint64_t)
-{
-  uint64_t cntpct_el0, cntfrq_el0;
-  R_SYSREG(cntpct_el0, cntpct_el0);
-  R_SYSREG(cntfrq_el0, cntfrq_el0);
-  DEBUG_EXCEP(cntpct_el0 / cntfrq_el0);
-
-  task_t task = {
-    .firing_tick = cntpct_el0 + 2 * cntfrq_el0,
-    .interval = 2 * cntfrq_el0,
-    .repeat = 1,
-
-    .func = _print_time,
-    .param = 0x0,
-  };
-  
-  add_timer_task(task);
-}
-
-static inline
-int32_t _test(uint64_t)
-{
-  for (int i = 0; i < 10; ++i) {
-    LOG(i); DEBUG_THREAD(get_current());
-    sleep(1000000);
-  }
-  return 0;
 }
 
 void main(void *dtb)
 {
-  file_node_t *initrd_root = 0x0;
+  _init(dtb);
-  _init(dtb, &initrd_root);
 
-  for (int i = 0; i < 3; ++i)
+  run_thread(run_process_by_name, (uint64_t)&"syscall.img");
-    run_thread(_test, 0x0);
 
   schedule();
 }

lib/logger.c

@@ -2,3 +2,5 @@
 
 char logger_buf[LOGGER_BUFLEN];
 char *logger_cur = logger_buf;
+char sp_buf[LOGGER_BUFLEN];
+char *sp_cur = sp_buf;

userprog/Makefile

@@ -13,6 +13,8 @@ LD := $(GNU)-ld
 LDFLAGS += -g -nostdlib -no-pie
 OBJCOPY := $(GNU)-objcopy
 
+INCLUDE := -I../include -Iinclude
+
 LD_SCRIPT := linker.ld
 SRCS := $(shell find . -name '*.[cS]')
 OBJS := $(SRCS:%=%.o)
@@ -29,11 +31,11 @@ userprog.elf: $(LD_SCRIPT) $(OBJS)
 
 %.S.o: %.S
 	mkdir -p $(dir $@)
-	$(CC) -c $< -o $@ $(CCFLAGS)
+	$(CC) -c $< -o $@ $(INCLUDE) $(CCFLAGS)
 
 %.c.o: %.c
 	mkdir -p $(dir $@)
-	$(CC) -c $< -o $@ $(CCFLAGS)
+	$(CC) -c $< -o $@ $(INCLUDE) $(CCFLAGS)
 
 clean:
 	-rm $(OBJS) userprog userprog.elf

userprog/include/syscall.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <stddef.h>
+
+uint64_t syscall(int32_t num, ...);
+
+int32_t getpid(void);
+size_t uart_read(char buf[], size_t size);
+size_t uart_write(const char buf[], size_t size);
+int32_t exec(const char *name, char *const argv[]);
+int32_t fork(void);
+void exit(int32_t status);
+int32_t mbox_call(uint8_t ch, uint32_t *mbox);
+void kill(int32_t pid);

userprog/lib/syscall.S

@@ -0,0 +1,13 @@
+.global syscall
+syscall:
+	mov x8, x0
+	mov x0, x1
+	mov x1, x2
+	mov x2, x3
+	mov x3, x4
+	mov x4, x5
+	mov x5, x6
+	mov x6, x7
+
+	svc 0
+	ret

userprog/lib/syscall.c

@@ -0,0 +1,25 @@
+#include <syscall.h>
+
+int32_t getpid()
+{ return (int32_t)syscall(0); }
+
+size_t uart_read(char buf[], size_t size)
+{ return (size_t)syscall(1, buf, size); }
+
+size_t uart_write(const char buf[], size_t size)
+{ return (size_t)syscall(2, buf, size); }
+
+int32_t exec(const char *name, char *const argv[])
+{ return (int32_t)syscall(3, name, argv); }
+
+int32_t fork(void)
+{ return (int32_t)syscall(4); }
+
+void exit(int32_t status)
+{ syscall(5); __builtin_unreachable(); }
+
+int32_t mbox_call(uint8_t ch, uint32_t *mbox)
+{ return (int32_t)syscall(6, ch, mbox); }
+
+void kill(int32_t pid)
+{ syscall(7, pid); }