kernel: vm: Add PMAP abstraction

Signed-off-by: sigsegv7 <ian@vegaa.systems>

5 files changed, 155 insertions, 1 deletions

diff --git a/share/man/man9/arch.9 b/share/man/man9/arch.9
index 6bcc317..47e864e 100644
--- a/share/man/man9/arch.9
+++ b/share/man/man9/arch.9
@@ -32,6 +32,7 @@
 .Sh SYNOPSIS
 .In sys/machdep.h
 .In machine/cpu.h
+.In machine/pmap.h
 .Sh DESCRIPTION
 NOTE: All examples will be for x86_64 but can be applied to others
 
@@ -72,5 +73,11 @@ to a
 .Ft cpu_info
 structure.
 
+In the
+.Ft machine/pmap.h
+header, should be a struct containing information
+about the address space. This header MUST be implemented
+or compiler errors will occur.
+
 .Sh AUTHORS
 .An Ian Moffett Aq Mt ian@vegaa.systems
diff --git a/sys/arch/amd64/pmap.c b/sys/arch/amd64/pmap.c
new file mode 100644
index 0000000..0da80d9
--- /dev/null
+++ b/sys/arch/amd64/pmap.c
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS 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 VegaOS 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 <vm/pmap.h>
+#include <sys/cdefs.h>
+
+#define PTE_ADDR_MASK 0x000FFFFFFFFFF000
+
+struct vas
+pmap_read_vas(void)
+{
+    struct vas vas;
+    uintptr_t cr3_raw;
+
+    __ASMV("mov %%cr3, %0"
+           : "=r" (cr3_raw)
+    );
+
+    vas.cr3_flags = cr3_raw & ~PTE_ADDR_MASK;
+    vas.top_level = cr3_raw & PTE_ADDR_MASK;
+    vas.use_l5_paging = false;      /* TODO: Check for support */
+    vas.lock.lock = 0;
+    return vas;
+}
diff --git a/sys/include/arch/amd64/vas.h b/sys/include/arch/amd64/vas.h
new file mode 100644
index 0000000..8284e8f
--- /dev/null
+++ b/sys/include/arch/amd64/vas.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS 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 VegaOS 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 _AMD64_PMAP_H_
+#define _AMD64_PMAP_H_
+
+#include <sys/types.h>
+#include <sys/spinlock.h>
+
+struct vas {
+    size_t cr3_flags;       /* CR3 flags */
+    uintptr_t top_level;    /* PML5 if `use_l5_paging' true, otherwise PML4 */
+    bool use_l5_paging;     /* True if 5-level paging is supported */
+    struct spinlock lock;
+};
+
+#endif  /* !_AMD64_PMAP_H_ */
diff --git a/sys/include/vm/pmap.h b/sys/include/vm/pmap.h
new file mode 100644
index 0000000..8dd6b7d
--- /dev/null
+++ b/sys/include/vm/pmap.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS 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 VegaOS 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_PMAP_H_
+#define _VM_PMAP_H_
+
+/*
+ * Each architecture is expected to implement
+ * this header. It should contain a `struct vas'
+ * which will contain information about a VAS
+ * (virtual address space)
+ *
+ * On AMD64 this struct contains: PML4, etc
+ *
+ * XXX: Compiler errors pointing to this include means you
+ *      forgot to implement it!!!
+ *
+ *      `struct vas' MUST have a `struct spinlock lock' field!!!
+ */
+#include <machine/vas.h>
+
+/*
+ * Read virtual address space descriptor
+ * and return it.
+ */
+struct vas pmap_read_vas(void);
+
+#endif  /* _VM_PMAP_H_ */
diff --git a/sys/include/vm/vm.h b/sys/include/vm/vm.h
index baf7677..e238cd0 100644
--- a/sys/include/vm/vm.h
+++ b/sys/include/vm/vm.h
@@ -34,6 +34,7 @@
 #include <sys/limine.h>
 #include <sys/cdefs.h>
 #include <vm/vm_page.h>
+#include <vm/pmap.h>
 
 extern volatile struct limine_hhdm_request g_hhdm_request;
 
@@ -55,6 +56,5 @@ vm_get_page_size(void)
 }
 
 void vm_init(void);
-struct vas vm_new_vas(void);
 
 #endif      /* !_VM_H_ */