kern: Add initial vm/ subsystem + hhdm helpers

Signed-off-by: Ian Moffett <ian@osmora.org>

3 files changed, 79 insertions, 0 deletions

diff --git a/sys/inc/vm/vm.h b/sys/inc/vm/vm.h
new file mode 100644
index 0000000..7bf24f1
--- /dev/null
+++ b/sys/inc/vm/vm.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2025 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 PURPKERNE
+ * 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; LKERNS 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
+ * PKERNSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _VM_VM_H_
+#define _VM_VM_H_ 1
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <lib/limine.h>
+
+extern volatile struct limine_hhdm_request hhdm_req;
+
+#define PHYS_TO_VIRT(PHYS) PTR_OFFSET(PHYS, hhdm_req.response->offset)
+#define VIRT_TO_PHYS(VIRT) (uintptr_t)PTR_NOFFET(VIRT, hhdm_req.response->offset)
+
+#endif  /* !_VM_VM_H_ */
diff --git a/sys/kern/Makefile b/sys/kern/Makefile
index 6252f1f..251bb8e 100644
--- a/sys/kern/Makefile
+++ b/sys/kern/Makefile
@@ -4,6 +4,7 @@ override PROMPT := printf "%s\t\t%s\n"
 CFILES = $(shell find . -name "*.c")
 CFILES += $(shell find ../lib -name "*.c")
 CFILES += $(shell find ../os -name "*.c")
+CFILES += $(shell find ../vm -name "*.c")
 OFILES = $(CFILES:.c=.o)
 CC =
 SYS_CFLAGS =
diff --git a/sys/vm/vm_hhdm.c b/sys/vm/vm_hhdm.c
new file mode 100644
index 0000000..fe1ea84
--- /dev/null
+++ b/sys/vm/vm_hhdm.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2025 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 PURPKERNE
+ * 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; LKERNS 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
+ * PKERNSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <vm/vm.h>
+#include <lib/limine.h>
+
+volatile struct limine_hhdm_request hhdm_req = {
+    .id = LIMINE_HHDM_REQUEST,
+    .revision = 0
+};