kern: vm: Add virtual memory mapping helpers

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

2 files changed, 158 insertions, 0 deletions

diff --git a/sys/inc/vm/map.h b/sys/inc/vm/map.h
new file mode 100644
index 0000000..a290b4d
--- /dev/null
+++ b/sys/inc/vm/map.h
@@ -0,0 +1,70 @@
+/*
+ * 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 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 _VM_MAP_H_
+#define _VM_MAP_H_
+
+#include <sys/types.h>
+#include <mu/mmu.h>
+
+struct vm_region {
+    uintptr_t pa;
+    uintptr_t va;
+    size_t page_count;
+    pagesize_t ps;
+};
+
+/*
+ * Map a contigious region of pages
+ *
+ * @vas: Address space to map within
+ * @region: Region to start mapping at
+ * @prot: Protection flags
+ * @ps: Desired pagesize
+ *
+ * Returns zero on success
+ */
+int vm_map_pages(
+    struct mmu_vas *vas, const struct vm_region *region,
+    uint16_t prot
+);
+
+/*
+ * Unmap a contigious range of pages
+ *
+ * @vas: Addresss space to unmap from
+ * @va: Virtual address to unmap
+ * @count: Number of pages to unmap
+ * @ps: Page size of region
+ *
+ * Returns zero on success
+ */
+int vm_unmap_pages(struct mmu_vas *vas, uintptr_t va, size_t count, pagesize_t ps);
+
+#endif  /* !_VM_MAP_H_ */
diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
new file mode 100644
index 0000000..f40d297
--- /dev/null
+++ b/sys/vm/vm_map.c
@@ -0,0 +1,88 @@
+/*
+ * 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 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/errno.h>
+#include <vm/map.h>
+#include <vm/vm.h>
+#include <mu/mmu.h>
+
+int
+vm_map_pages(struct mmu_vas *vas, const struct vm_region *region, uint16_t prot)
+{
+    uintptr_t va, pa;
+    int error;
+
+    if (vas == NULL || region == NULL) {
+        return -EINVAL;
+    }
+
+    va = ALIGN_DOWN(region->va, PAGESIZE);
+    pa = ALIGN_DOWN(region->pa, PAGESIZE);
+    for (size_t i = 0; i < region->page_count; ++i) {
+        error = mu_pmap_map(
+            vas,
+            pa + (i*PAGESIZE),
+            va + (i*PAGESIZE),
+            prot,
+            region->ps
+        );
+
+        if (error < 0) {
+            vm_unmap_pages(vas, va, i, region->ps);
+            return error;
+        }
+    }
+
+    return 0;
+}
+
+int
+vm_unmap_pages(struct mmu_vas *vas, uintptr_t va, size_t count, pagesize_t ps)
+{
+    int error;
+
+    if (vas == NULL) {
+        return -EINVAL;
+    }
+
+    for (size_t i = 0; i < count; ++i) {
+        error = mu_pmap_unmap(
+            vas,
+            va + (i*PAGESIZE),
+            ps
+        );
+
+        if (error < 0) {
+            return error;
+        }
+    }
+
+    return 0;
+}