Implement an ATA driver, Add vfsmount/vfsunmount syscalls

kernel/hal/x86_64/gdt.c

@@ -7,7 +7,7 @@
 #define GDT_PRESENT 0x80
 #define GDT_TSS     0x89
 
-#define KSTACK (1024*4*4096)
+#define KSTACK (1024*2*4096)
 ALIGNED(16) static uint8_t kernelstack[KSTACK];
 
 typedef struct {

kernel/hal/x86_64/io.c

@@ -26,3 +26,21 @@ uint32_t io_in32(uint16_t port) {
 void io_out32(uint16_t port, uint32_t value) {
   asm volatile("outl %%eax, %%dx" :: "d"(port), "a"(value));
 }
+
+void io_ins16(uint16_t port, void *addr, int cnt) {
+  asm volatile(
+    "cld; rep insw"
+    : "+D"(addr), "+c"(cnt)
+    : "d"(port)
+    : "memory", "cc"
+  );
+}
+
+void io_outs16(uint16_t port, const void *addr, int cnt) {
+  asm volatile(
+    "cld; rep outsw"
+    : "+S"(addr), "+c"(cnt)
+    : "d"(port)
+    : "memory", "cc"
+  );
+}

kernel/hal/x86_64/io.h

@@ -12,4 +12,7 @@ void io_out16(uint16_t port, uint16_t value);
 uint32_t io_in32(uint16_t port);
 void io_out32(uint16_t port, uint32_t value);
 
+void io_ins16(uint16_t port, void *addr, int cnt);
+void io_outs16(uint16_t port, const void *addr, int cnt);
+
 #endif // HAL_IO_H_