feat: establish bootable new architecture checkpoint

Replace the compressed boot path with a relocatable higher-half RISC-V entry, expand memory and SMP support, and add the driver, TTY, VFS, exec, signal, syscall, initramfs, and self-test infrastructure needed for a bootable kernel checkpoint.

1 files changed, 164 insertions, 0 deletions

diff --git a/na/fs/file_table.cc b/na/fs/file_table.cc
new file mode 100644
index 0000000..06095c1
--- /dev/null
+++ b/na/fs/file_table.cc
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+/*
+ * file_table.cc — Open file allocation and reference counting
+ */
+
+#include <lume/file.h>
+#include <lume/fs.h>
+#include <lume/dcache.h>
+#include <lume/slab.h>
+#include <lume/errno.h>
+
+/* ================================================================== */
+/*  alloc_empty_file                                                  */
+/* ================================================================== */
+
+file* alloc_empty_file(int flags)
+{
+    auto* fp = new file{};
+    if (!fp) return nullptr;
+
+    fp->f_count.store(1);
+    fp->f_flags = flags;
+    fp->f_mode = 0;
+    fp->f_op = nullptr;
+    fp->f_mapping = nullptr;
+    fp->f_inode = nullptr;
+    fp->f_pos = 0;
+    fp->private_data = nullptr;
+    fp->f_path.mnt = nullptr;
+    fp->f_path.de = nullptr;
+
+    /* Derive f_mode from O_* flags */
+    int acc = flags & O_ACCMODE;
+    if (acc == O_RDONLY)
+        fp->f_mode = FMODE_READ | FMODE_CAN_READ;
+    else if (acc == O_WRONLY)
+        fp->f_mode = FMODE_WRITE | FMODE_CAN_WRITE;
+    else if (acc == O_RDWR)
+        fp->f_mode = FMODE_READ | FMODE_WRITE | FMODE_CAN_READ | FMODE_CAN_WRITE;
+
+    fp->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
+
+    return fp;
+}
+
+/* ================================================================== */
+/*  get_file / fput                                                   */
+/* ================================================================== */
+
+file* get_file(file* f)
+{
+    f->f_count.fetch_add(1);
+    return f;
+}
+
+void fput(file* fp)
+{
+    if (!fp) return;
+
+    int old = fp->f_count.fetch_sub(1);
+    if (old > 1) return;
+
+    /* Last reference — release */
+    if (fp->f_op && fp->f_op->release)
+        fp->f_op->release(fp->f_inode, fp);
+
+    if (fp->f_path.de)
+        dput(fp->f_path.de);
+
+    /* Future: mntput(fp->f_path.mnt) */
+
+    delete fp;
+}
+
+/* ================================================================== */
+/*  vfs_read / vfs_write / vfs_llseek / vfs_fstat                     */
+/* ================================================================== */
+
+int64 vfs_read(file* fp, char* buf, uint64 count, int64* pos)
+{
+    if (!(fp->f_mode & FMODE_CAN_READ))
+        return -EBADF;
+    if (!fp->f_op || !fp->f_op->read)
+        return -EINVAL;
+
+    return fp->f_op->read(fp, buf, count, pos);
+}
+
+int64 vfs_write(file* fp, const char* buf, uint64 count, int64* pos)
+{
+    if (!(fp->f_mode & FMODE_CAN_WRITE))
+        return -EBADF;
+    if (!fp->f_op || !fp->f_op->write)
+        return -EINVAL;
+
+    return fp->f_op->write(fp, buf, count, pos);
+}
+
+int64 vfs_llseek(file* fp, int64 offset, int whence)
+{
+    if (fp->f_op && fp->f_op->llseek)
+        return fp->f_op->llseek(fp, offset, whence);
+    return generic_file_llseek(fp, offset, whence);
+}
+
+int64 generic_file_llseek(file* fp, int64 offset, int whence)
+{
+    int64 new_pos;
+    switch (whence) {
+    case SEEK_SET:
+        new_pos = offset;
+        break;
+    case SEEK_CUR:
+        new_pos = fp->f_pos + offset;
+        break;
+    case SEEK_END:
+        new_pos = fp->f_inode->i_size + offset;
+        break;
+    default:
+        return -EINVAL;
+    }
+
+    if (new_pos < 0) return -EINVAL;
+    fp->f_pos = new_pos;
+    return new_pos;
+}
+
+int vfs_fstat(file* fp, kstat* stat)
+{
+    inode* ip = file_inode(fp);
+    if (!ip) return -EBADF;
+
+    if (ip->i_op && ip->i_op->getattr) {
+        return ip->i_op->getattr(&fp->f_path, stat, 0, 0);
+    }
+
+    generic_fillattr(ip, stat);
+    return 0;
+}
+
+/* ================================================================== */
+/*  path_get / path_put (simplified)                                  */
+/* ================================================================== */
+
+void path_get(const path* p)
+{
+    if (p->de) dget(p->de);
+    /* Future: mntget(p->mnt) */
+}
+
+void path_put(const path* p)
+{
+    if (p->de) dput(p->de);
+    /* Future: mntput(p->mnt) */
+}
+
+/* ================================================================== */
+/*  mntget / mntput (stubs for Phase 1)                               */
+/* ================================================================== */
+
+vfsmount* mntget(vfsmount* mnt) { return mnt; }
+void mntput(vfsmount*) {}