4 files changed, 184 insertions, 2 deletions

diff --git a/src/sys/include/compat/unix/syscall.h b/src/sys/include/compat/unix/syscall.h
index daca2dc..a3e7257 100644
--- a/src/sys/include/compat/unix/syscall.h
+++ b/src/sys/include/compat/unix/syscall.h
@@ -35,11 +35,15 @@
 #include <sys/syscall.h>
 
 /*
- * Syscall numbers
+ * Default syscall numbers
+ *
+ * Defines marked as (mandatory) must be implemented
+ * between latches.
  */
 #define SYS_none    0x00
 #define SYS_exit    0x01
 #define SYS_write   0x02
+#define SYS_cross   0x03    /* cross a border (mandatory) */
 
 /*
  * Exit the current process - exit(2) syscall
@@ -51,11 +55,17 @@ scret_t sys_exit(struct syscall_args *scargs);
  */
 scret_t sys_write(struct syscall_args *scargs);
 
+/*
+ * Cross a resource border - L5 mandatory
+ */
+scret_t sys_cross(struct syscall_args *scargs);
+
 #ifdef _NEED_UNIX_SCTAB
 scret_t(*g_unix_sctab[])(struct syscall_args *) = {
     [SYS_none]   = NULL,
     [SYS_exit]   = sys_exit,
-    [SYS_write]  = sys_write
+    [SYS_write]  = sys_write,
+    [SYS_cross]  = sys_cross
 };
 
 #endif  /* !_NEED_UNIX_SCTAB */
diff --git a/src/sys/include/io/video/fbdev.h b/src/sys/include/io/video/fbdev.h
new file mode 100644
index 0000000..0502d46
--- /dev/null
+++ b/src/sys/include/io/video/fbdev.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * 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 the project 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.
+ */
+
+#ifndef _VIDEO_FBDEV_H_
+#define _VIDEO_FBDEV_H_
+
+#include <os/mac.h>
+
+extern struct mac_border g_fbdev_border;
+
+#endif  /* !_VIDEO_FBDEV_H_ */
diff --git a/src/sys/include/os/mac.h b/src/sys/include/os/mac.h
new file mode 100644
index 0000000..dbc09eb
--- /dev/null
+++ b/src/sys/include/os/mac.h
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * 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 the project 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.
+ */
+
+#ifndef _OS_MAC_H_
+#define _OS_MAC_H_ 1
+
+#include <sys/types.h>
+
+/* Forward declarations */
+struct mac_border;
+struct proc;
+
+typedef enum {
+    BORDER_NONE,
+    BORDER_FBDEV,
+    __BORDER_MAX
+} border_id_t;
+
+/*
+ * MAC levels
+ *
+ * Processes or users with lower levels cannot
+ * access higher levels, higher levels can access
+ * lower levels.
+ */
+typedef enum {
+    MAC_GLOBAL,
+    MAC_RESTRICTED,
+    MAC_SECRET
+} mac_level_t;
+
+/*
+ * Mapping arguments for MAC
+ *
+ * @off: Mapping offset
+ * @len: Mapping length
+ * @flags: Optional flags
+ * @dp_res: Data pointer result written here
+ */
+struct mac_map_args {
+    off_t off;
+    size_t len;
+    int flags;
+    void **dp_res;
+};
+
+/*
+ * MAC operation hooks
+ *
+ * @map: Map a resource, return length
+ * @sync: Sync resource with driver
+ * @getattr: Get attributes of resource
+ */
+struct mac_ops {
+    ssize_t(*map)(struct mac_border *mbp, struct mac_map_args *args);
+    int(*sync)(struct mac_border *mbp, int flags);
+    int(*getattr)(struct mac_border *mbp, void *p, size_t len);
+};
+
+/*
+ * A MAC border sits inbetween a resource and the user
+ * and controls if they can access it or not.
+ */
+struct mac_border {
+    mac_level_t level;
+    struct mac_ops *ops;
+};
+
+/*
+ * Check creds with a specific process and a specific
+ * resource border.
+ *
+ * @procp: Process to check with border
+ * @mbp: Border to 'procp' is trying to access
+ *
+ * Returns zero if the check passed, otherwise a less than
+ * zero value if the check failed.
+ */
+int mac_check_creds(struct proc *procp, struct mac_border *mbp);
+
+/*
+ * Map a resource into process address space by
+ * going through its border
+ *
+ * @mbp: Border of resource
+ * @off: Offset of mapping to make
+ * @len: Length of mapping to make
+ * @res: Result pointer is written here
+ * @flags: Optional flags
+ *
+ * Returns zero on success, otherwise a less than zero value
+ * on failure.
+ */
+int mac_map(struct mac_border *mbp, off_t off, size_t len, void **res, int flags);
+
+/*
+ * Acquire a specific border using an ID
+ *
+ * @id: ID to lookup
+ *
+ * Returns the pointer pointer on success, otherwise a NULL
+ * value on failure.
+ */
+struct mac_border *mac_get_border(border_id_t id);
+
+#endif  /* !_OS_MAC_H_ */
diff --git a/src/sys/include/sys/proc.h b/src/sys/include/sys/proc.h
index 6a356ef..43772be 100644
--- a/src/sys/include/sys/proc.h
+++ b/src/sys/include/sys/proc.h
@@ -35,6 +35,7 @@
 #include <sys/cdefs.h>
 #include <sys/param.h>
 #include <sys/queue.h>
+#include <os/mac.h>
 #include <vm/vm.h>
 #include <machine/pcb.h>    /* standard */
 
@@ -53,6 +54,7 @@
  * @flags: State flags (see PROC_*)
  * @pcb: Process control block
  * @scdom: Syscall domain
+ * @level: Access level
  * @maplist: List of mapped regions
  * @link: TAILQ link
  */
@@ -61,6 +63,7 @@ struct proc {
     uint32_t flags;
     struct md_pcb pcb;
     struct syscall_domain scdom;
+    mac_level_t level;
     TAILQ_HEAD(, vm_range) maplist;
     TAILQ_ENTRY(proc) link;
 };