Import hyra expt

9 files changed, 810 insertions, 0 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
new file mode 100644
index 0000000..df955ee
--- /dev/null
+++ b/sys/kern/init_main.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/reboot.h>
+#include <sys/syslog.h>
+#include <sys/sched.h>
+#include <sys/mount.h>
+#include <sys/proc.h>
+#include <dev/cons/cons.h>
+#include <dev/acpi/acpi.h>
+#include <machine/cpu.h>
+#include <vm/vm.h>
+
+static struct proc proc0;
+
+int
+main(void)
+{
+    /* Startup the console */
+    cons_init();
+    kprintf("Starting Hyra/%s v%s: %s\n", HYRA_ARCH, HYRA_VERSION,
+        HYRA_BUILDDATE);
+
+    /* Start the ACPI subsystem */
+    acpi_init();
+
+    /* Init the virtual memory subsystem */
+    vm_init();
+
+    /* Startup the BSP */
+    cpu_startup(&g_bsp_ci);
+
+    /* Init process 0 */
+    md_td_init(&proc0, NULL, 0);
+
+    /* Init the virtual file system */
+    vfs_init();
+
+    /* Start scheduler and bootstrap APs */
+    sched_init();
+    mp_bootstrap_aps(&g_bsp_ci);
+
+    /* Nothing left to do... halt */
+    cpu_reboot(REBOOT_HALT);
+    __builtin_unreachable();
+}
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
new file mode 100644
index 0000000..64e0caf
--- /dev/null
+++ b/sys/kern/kern_fork.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/proc.h>
+#include <sys/errno.h>
+#include <sys/sched.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+static size_t nthreads = 0;
+
+/*
+ * Fork1 - fork and direct a thread to 'ip'
+ *
+ * @cur: Current process.
+ * @flags: Flags to set.
+ * @ip: Location for new thread to start at.
+ * @newprocp: Will contain new thread if not NULL.
+ */
+int
+fork1(struct proc *cur, int flags, void(*ip)(void), struct proc **newprocp)
+{
+    struct proc *newproc;
+    int status = 0;
+
+    newproc = dynalloc(sizeof(*newproc));
+    if (newproc == NULL)
+        return -ENOMEM;
+
+    /*
+     * We want to zero the proc to ensure it is in known
+     * state. We then want to initialize machine dependent
+     * fields.
+     */
+    memset(newproc, 0, sizeof(*newproc));
+    status = md_td_init(newproc, cur, (uintptr_t)ip);
+    if (status != 0)
+        goto done;
+
+    /* Set proc output if we can */
+    if (newprocp != NULL)
+        *newprocp = newproc;
+
+    newproc->pid = nthreads++;
+    sched_enqueue_td(newproc);
+done:
+    if (status != 0)
+        dynfree(newproc);
+
+    return status;
+}
diff --git a/sys/kern/kern_lock.c b/sys/kern/kern_lock.c
new file mode 100644
index 0000000..9047a21
--- /dev/null
+++ b/sys/kern/kern_lock.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/spinlock.h>
+#include <sys/types.h>
+
+void
+spinlock_acquire(struct spinlock *lock)
+{
+    while (__atomic_test_and_set(&lock->lock, __ATOMIC_ACQUIRE));
+}
+
+void
+spinlock_release(struct spinlock *lock)
+{
+    __atomic_clear(&lock->lock, __ATOMIC_RELEASE);
+}
diff --git a/sys/kern/kern_panic.c b/sys/kern/kern_panic.c
new file mode 100644
index 0000000..0a17456
--- /dev/null
+++ b/sys/kern/kern_panic.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/panic.h>
+#include <sys/spinlock.h>
+#include <sys/syslog.h>
+#include <sys/reboot.h>
+
+/*
+ * Tells the user something terribly wrong happened then
+ * halting the system as soon as possible.
+ *
+ * XXX: There is no need to cleanup stuff here (e.g `va_list ap`)
+ *      as we won't be returning from here anyways and the source
+ *      of the panic could be *anywhere* so it's best not to mess with
+ *      things.
+ */
+void
+panic(const char *fmt, ...)
+{
+    va_list ap;
+    static struct spinlock lock = {0};
+
+    spinlock_acquire(&lock);    /* Never released */
+    va_start(ap, fmt);
+
+    kprintf(OMIT_TIMESTAMP "panic: ");
+    vkprintf(fmt, &ap);
+
+    cpu_reboot(REBOOT_HALT);
+    __builtin_unreachable();
+}
diff --git a/sys/kern/kern_sched.c b/sys/kern/kern_sched.c
new file mode 100644
index 0000000..c370311
--- /dev/null
+++ b/sys/kern/kern_sched.c
@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/sched.h>
+#include <sys/schedvar.h>
+#include <sys/cdefs.h>
+#include <sys/syslog.h>
+#include <machine/frame.h>
+#include <machine/cpu.h>
+#include <vm/pmap.h>
+#include <dev/timer.h>
+#include <assert.h>
+#include <string.h>
+
+#define pr_trace(fmt, ...) kprintf("ksched: " fmt, ##__VA_ARGS__)
+
+void sched_switch(struct trapframe *tf);
+
+static sched_policy_t policy = SCHED_POLICY_RR;
+
+/*
+ * Thread ready queues - all threads ready to be
+ * scheduled should be added to the toplevel queue.
+ */
+static struct sched_queue qlist[SCHED_NQUEUE];
+
+/*
+ * Thread queue lock - all operations to `qlist'
+ * must be done with this lock acquired.
+ */
+__cacheline_aligned static struct spinlock tdq_lock = {0};
+
+/*
+ * Perform timer oneshot
+ */
+static inline void
+sched_oneshot(bool now)
+{
+    struct timer timer;
+    size_t usec = now ? SHORT_TIMESLICE_USEC : DEFAULT_TIMESLICE_USEC;
+    tmrr_status_t tmr_status;
+
+    tmr_status = req_timer(TIMER_SCHED, &timer);
+    __assert(tmr_status == TMRR_SUCCESS);
+
+    timer.oneshot_us(usec);
+}
+
+static struct proc *
+sched_dequeue_td(void)
+{
+    struct sched_queue *queue;
+    struct proc *td = NULL;
+
+    spinlock_acquire(&tdq_lock);
+
+    for (size_t i = 0; i < SCHED_NQUEUE; ++i) {
+        queue = &qlist[i];
+        if (!TAILQ_EMPTY(&queue->q)) {
+            td = TAILQ_FIRST(&queue->q);
+            TAILQ_REMOVE(&queue->q, td, link);
+            break;
+        }
+    }
+
+    spinlock_release(&tdq_lock);
+    return td;
+}
+
+/*
+ * Add a thread to the scheduler.
+ */
+void
+sched_enqueue_td(struct proc *td)
+{
+    struct sched_queue *queue;
+
+    spinlock_acquire(&tdq_lock);
+    queue = &qlist[td->priority];
+
+    TAILQ_INSERT_TAIL(&queue->q, td, link);
+    spinlock_release(&tdq_lock);
+}
+
+/*
+ * Return the currently running thread.
+ */
+struct proc *
+this_td(void)
+{
+    struct cpu_info *ci;
+
+    ci = this_cpu();
+    return ci->curtd;
+}
+
+/*
+ * Perform a context switch.
+ *
+ * TODO
+ */
+void
+sched_switch(struct trapframe *tf)
+{
+    struct cpu_info *ci;
+    struct pcb *pcbp;
+    struct proc *next_td, *td;
+
+    ci = this_cpu();
+    td = ci->curtd;
+
+    /* Do we have threads to switch to? */
+    if ((next_td = sched_dequeue_td()) == NULL) {
+        sched_oneshot(false);
+        return;
+    }
+
+    /* Re-enqueue the old thread */
+    if (td != NULL) {
+        memcpy(&td->tf, tf, sizeof(td->tf));
+        sched_enqueue_td(td);
+    }
+
+    memcpy(tf, &next_td->tf, sizeof(*tf));
+    ci->curtd = next_td;
+    pcbp = &next_td->pcb;
+
+    pmap_switch_vas(pcbp->addrsp);
+    sched_oneshot(false);
+}
+
+/*
+ * Main scheduler loop
+ */
+void
+sched_enter(void)
+{
+    sched_oneshot(false);
+    for (;;);
+}
+
+void
+sched_init(void)
+{
+    /* Setup the queues */
+    for (int i = 0; i < SCHED_NQUEUE; ++i) {
+        TAILQ_INIT(&qlist[i].q);
+    }
+
+    pr_trace("Prepared %d queues (policy=0x%x)\n",
+        SCHED_NQUEUE, policy);
+}
diff --git a/sys/kern/kern_syslog.c b/sys/kern/kern_syslog.c
new file mode 100644
index 0000000..6962a69
--- /dev/null
+++ b/sys/kern/kern_syslog.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/syslog.h>
+#include <sys/spinlock.h>
+#include <dev/cons/cons.h>
+#include <dev/timer.h>
+#include <stdarg.h>
+#include <string.h>
+
+/* Global logger lock */
+static struct spinlock lock = {0};
+
+static void
+syslog_write(const char *s, size_t len)
+{
+    const char *p = s;
+
+    while (len--) {
+        cons_putch(&g_root_scr, *p);
+        ++p;
+    }
+}
+
+/*
+ * XXX: Not serialized
+ */
+void
+vkprintf(const char *fmt, va_list *ap)
+{
+    char buffer[1024] = {0};
+
+    vsnprintf(buffer, sizeof(buffer), fmt, *ap);
+    syslog_write(buffer, strlen(buffer));
+}
+
+void
+kprintf(const char *fmt, ...)
+{
+    va_list ap;
+    char timestamp[64] = "[  0.000000] ";
+    const char *fmt_p = fmt;
+    bool use_timestamp = true;
+    bool has_counter = true;
+    struct timer tmr;
+
+    /*
+     * If the first char is OMIT_TIMESTAMP, then we won't
+     * print out the timestamp.
+     */
+    if (*fmt == OMIT_TIMESTAMP[0]) {
+        ++fmt_p;
+        use_timestamp = false;
+    }
+
+    /* See if we have a timer */
+    if (req_timer(TIMER_GP, &tmr) != TMRR_SUCCESS) {
+        has_counter = false;
+    }
+
+    /* If we can use the counter, format the timestamp */
+    if (has_counter) {
+        if (tmr.get_time_sec != NULL && tmr.get_time_usec != NULL) {
+            snprintf(timestamp, sizeof(timestamp), "[  %d.%06d] ",
+                tmr.get_time_sec(), tmr.get_time_usec());
+        }
+    }
+
+    if (use_timestamp) {
+        syslog_write(timestamp, strlen(timestamp));
+    }
+
+    spinlock_acquire(&lock);
+    va_start(ap, fmt);
+
+    vkprintf(fmt_p, &ap);
+    va_end(ap);
+    spinlock_release(&lock);
+}
diff --git a/sys/kern/vfs_init.c b/sys/kern/vfs_init.c
new file mode 100644
index 0000000..aafbc00
--- /dev/null
+++ b/sys/kern/vfs_init.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/mount.h>
+#include <sys/vnode.h>
+#include <sys/panic.h>
+#include <string.h>
+
+struct vnode *g_root_vnode = NULL;
+static struct fs_info fs_list[] = {
+    {MOUNT_RAMFS, &g_initramfs_vfsops, 0, 0},
+};
+
+void
+vfs_init(void)
+{
+    struct fs_info *fs;
+    const struct vfsops *vfsops;
+
+    TAILQ_INIT(&g_mountlist);
+
+    for (size_t i= 0; i < NELEM(fs_list); ++i) {
+        fs = &fs_list[i];
+        vfsops = fs->vfsops;
+
+        /* Try to initialize the filesystem */
+        if (vfsops->init != NULL) {
+            vfsops->init(fs);
+        }
+    }
+}
+
+struct fs_info *
+vfs_byname(const char *name)
+{
+    for (int i = 0; i < NELEM(fs_list); ++i) {
+        if (strcmp(fs_list[i].name, name) == 0) {
+            return &fs_list[i];
+        }
+    }
+
+    return NULL;
+}
diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
new file mode 100644
index 0000000..83924c6
--- /dev/null
+++ b/sys/kern/vfs_lookup.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/namei.h>
+#include <sys/vnode.h>
+#include <sys/errno.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+/*
+ * Convert a path to a vnode.
+ *
+ * @ndp: Nameidata containing the path and resulting
+ *       vnode.
+ *
+ * TODO: Add support for lookups with individual
+ *       path components
+ */
+int
+namei(struct nameidata *ndp)
+{
+    struct vnode *vp;
+    struct vop_lookup_args lookup_args;
+    const char *path = ndp->path;
+    int status;
+
+    if (path == NULL) {
+        return -EINVAL;
+    }
+
+    /* Path must start with "/" */
+    if (*path != '/') {
+        return -EINVAL;
+    }
+
+    /* Just return the root vnode if we can */
+    if (strcmp(path, "/") == 0) {
+        ndp->vp = g_root_vnode;
+        return 0;
+    }
+
+    /*
+     * Some filesystems (like initramfs) may only understand
+     * full paths, so try passing it through.
+     */
+    lookup_args.name = path;
+    lookup_args.dirvp = g_root_vnode;
+    lookup_args.vpp = &vp;
+    status = vfs_vop_lookup(lookup_args.dirvp, &lookup_args);
+
+    if (status != 0) {
+        return status;
+    }
+
+    ndp->vp = vp;
+    return 0;
+}
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
new file mode 100644
index 0000000..04d64e3
--- /dev/null
+++ b/sys/kern/vfs_subr.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/vnode.h>
+#include <sys/errno.h>
+#include <sys/mount.h>
+#include <vm/dynalloc.h>
+#include <string.h>
+
+mountlist_t g_mountlist;
+
+int
+vfs_alloc_vnode(struct vnode **res, int type)
+{
+    struct vnode *vp = dynalloc(sizeof(struct vnode));
+
+    if (vp == NULL) {
+        return -ENOMEM;
+    }
+
+    memset(vp, 0, sizeof(*vp));
+    vp->type = type;
+    *res = vp;
+    return 0;
+}
+
+/*
+ * Allocate a mount structure.
+ *
+ * @vp: Vnode this mount structure covers.
+ * @fip: File system information.
+ */
+struct mount *
+vfs_alloc_mount(struct vnode *vp, struct fs_info *fip)
+{
+    struct mount *mp;
+
+    mp = dynalloc(sizeof(*mp));
+
+    if (mp == NULL) {
+        return NULL;
+    }
+
+    memset(mp, 0, sizeof(*mp));
+    mp->vp = vp;
+    mp->mnt_ops = fip->vfsops;
+    return mp;
+}
+
+/*
+ * Release a vnode and its resources from
+ * memory.
+ */
+int
+vfs_release_vnode(struct vnode *vp)
+{
+    const struct vops *vops = vp->vops;
+    int status = 0;
+
+    if (vp == NULL) {
+        return -EINVAL;
+    }
+
+    if (vops->reclaim != NULL) {
+        status = vops->reclaim(vp);
+    }
+
+    dynfree(vp);
+    return status;
+}
+
+int
+vfs_vop_lookup(struct vnode *vp, struct vop_lookup_args *args)
+{
+    const struct vops *vops = vp->vops;
+
+    if (vops == NULL)
+        return -EIO;
+    if (vops->lookup == NULL)
+        return -EIO;
+
+    return vops->lookup(args);
+}
+
+int
+vfs_vop_read(struct vnode *vp, struct sio_txn *sio)
+{
+    const struct vops *vops = vp->vops;
+
+    if (vops == NULL)
+        return -EIO;
+    if (vops->read == NULL)
+        return -EIO;
+
+    return vops->read(vp, sio);
+}