Start isolating processes

Kernel moved to a fixed range high in address space. Memory allocation
now happens per process. Single kernel process added.

src/fs.c

@@ -1,30 +1,31 @@
 #include "src/fs.h"
 #include "src/fat16.h"
+#include "src/process.h"
 
-fs_node_t *fs_mount() {
-  return fat16_mount();
+fs_node_t *fs_mount(process_t *kernel) {
+  return fat16_mount(kernel);
 }
 
-fs_node_t *fs_open_by(const fs_node_t *directory, const char *name) {
-  return fat16_open_by(directory, name);
+fs_node_t *fs_open_by(process_t *proc, const fs_node_t *directory, const char *name) {
+  return fat16_open_by(proc, directory, name);
 }
 
-fs_node_t *fs_open_at(const fs_node_t *directory, uint64_t index) {
-  return fat16_open_at(directory, index);
+fs_node_t *fs_open_at(process_t *proc, const fs_node_t *directory, uint64_t index) {
+  return fat16_open_at(proc, directory, index);
 }
 
-fs_node_t *fs_open_again(const fs_node_t *source) {
-  return fat16_open_again(source);
+fs_node_t *fs_open_again(process_t *proc, const fs_node_t *source) {
+  return fat16_open_again(proc, source);
 }
 
-void fs_read(const fs_node_t *file, uint64_t offset, uint64_t size, void *to) {
-  fat16_read(file, offset, size, to);
+void fs_read(process_t *proc, const fs_node_t *file, uint64_t offset, uint64_t size, void *to) {
+  fat16_read(proc, file, offset, size, to);
 }
 
-void fs_close(fs_node_t *node) {
-  fat16_close(node);
+void fs_close(process_t *proc, fs_node_t *node) {
+  fat16_close(proc, node);
 }
 
-void fs_unmount(fs_node_t *fs) {
-  fat16_unmount(fs);
+void fs_unmount(process_t *kernel, fs_node_t *fs) {
+  fat16_unmount(kernel, fs);
 }