kern: vm: Add MI vm_map() function

Introduce a machine independent mechanism to map multiple pages through
the new vm_map() function

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

2 files changed, 160 insertions, 0 deletions

diff --git a/src/sys/include/vm/map.h b/src/sys/include/vm/map.h
new file mode 100644
index 0000000..4e0f27e
--- /dev/null
+++ b/src/sys/include/vm/map.h
@@ -0,0 +1,52 @@
+/*
+ * 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 _VM_MAP_H_
+#define _VM_MAP_H_  1
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <machine/vas.h>    /* standard */
+#include <vm/mmu.h>
+#include <vm/vm.h>
+
+/*
+ * Create a virtual to physical memory mapping
+ *
+ * @vas: Virtual address space to use
+ * @map: Mapping specifier
+ * @len: Length of mapping (4K aligned)
+ * @prot: Memory protection flags (PROT_*)
+ *
+ * Returns zero on success, otherwise a less than zero value
+ * on failure.
+ */
+int vm_map(struct vm_vas *vas, struct mmu_map *spec, size_t len, int prot);
+
+#endif  /* !_VM_MAP_H_ */
diff --git a/src/sys/vm/vm_map.c b/src/sys/vm/vm_map.c
new file mode 100644
index 0000000..ed187d8
--- /dev/null
+++ b/src/sys/vm/vm_map.c
@@ -0,0 +1,108 @@
+/*
+ * 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.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/syslog.h>
+#include <vm/mmu.h>
+#include <vm/map.h>
+#include <vm/vm.h>
+
+/*
+ * Create a virtual to physical memory
+ * mapping
+ */
+static int
+__vm_map(struct vm_vas *vas, struct mmu_map *spec, size_t len, int prot)
+{
+    const size_t PSIZE = DEFAULT_PAGESIZE;
+    vaddr_t va_cur, va_end;
+    vaddr_t va_start;
+    int error;
+
+    if (vas == NULL || spec == NULL) {
+        return -EINVAL;
+    }
+
+    if (len == 0) {
+        return -EINVAL;
+    }
+
+    /* Must be 4K aligned */
+    len = ALIGN_UP(len, PSIZE);
+    spec->va = ALIGN_DOWN(spec->va, PSIZE);
+    spec->pa = ALIGN_DOWN(spec->pa, PSIZE);
+
+    /*
+     * start: always the mapping base
+     * cur: current pointer sliding around
+     * end: region end
+     */
+    va_start = spec->va;
+    va_cur = spec->va;
+    va_end = spec->va + len;
+
+    while (va_cur < va_end) {
+        error = mmu_map_single(vas, spec, prot);
+        if (error < 0) {
+            return spec->va;
+        }
+
+        va_cur += PSIZE;
+        spec->va += PSIZE;
+        spec->pa += PSIZE;
+    }
+
+    return 0;
+}
+
+int
+vm_map(struct vm_vas *vas, struct mmu_map *spec, size_t len, int prot)
+{
+    int retval;
+    size_t unmap_len;
+    struct mmu_map spec_cpy;
+
+    if (spec != NULL) {
+        spec_cpy = *spec;
+    }
+
+    /* If this fails, unmap the partial region */
+    retval = __vm_map(vas, spec, len, prot);
+    if (retval != 0) {
+        printf("vm_map: could not map <%p>\n", spec_cpy.va);
+        unmap_len = retval - spec_cpy.va;
+
+        __vm_map(vas, &spec_cpy, unmap_len, 0);
+        return -1;
+    }
+
+    return 0;
+}