From 51cbabd0f40b041fa00203266afa046d14e88b22 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 17 Jul 2022 14:39:45 +0200
Subject: amd64: remove dead code, combine shared code

---
 src/kernel/arch/amd64/paging.h | 54 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 src/kernel/arch/amd64/paging.h

(limited to 'src/kernel/arch/amd64/paging.h')

diff --git a/src/kernel/arch/amd64/paging.h b/src/kernel/arch/amd64/paging.h
new file mode 100644
index 0000000..a676bb8
--- /dev/null
+++ b/src/kernel/arch/amd64/paging.h
@@ -0,0 +1,54 @@
+#pragma once
+#include <shared/types.h>
+
+/* <heat> nitpick: I highly recommend you dont use bitfields for paging
+ *        structures
+ * <heat> you can't change them atomically and the way they're layed out
+ *        in memory is implementation defined iirc
+ */
+typedef union pe_generic_t {
+	struct {
+		uint64_t present   : 1;
+		uint64_t writeable : 1;
+		uint64_t user      : 1;
+		uint64_t writethru : 1;
+
+		uint64_t uncached  : 1;
+		uint64_t accessed  : 1;
+		uint64_t dirty     : 1;
+		uint64_t large     : 1; // also, PAT
+
+		uint64_t global    : 1; // CR4.PGE is disabled anyways
+		uint64_t _unused2  : 2;
+		uint64_t _unused3  : 1; // HLAT
+
+		uint64_t address   : 40;
+
+		uint64_t _unused4  : 7;
+		uint64_t pke       : 4;
+		uint64_t noexec    : 1;
+	} __attribute__((packed));
+	void *as_ptr;
+} pe_generic_t; // pageentry_generic
+
+struct pagedir { // on amd64 actually points to pml4. TODO more sensible type
+	pe_generic_t e[512];
+} __attribute__((packed));
+
+
+union virt_addr {
+	void __user *full;
+	struct {
+		uint64_t off_4k : 12; //   4Kb // offset in page
+		uint64_t pt     :  9; //   2Mb // page table index
+		uint64_t pd     :  9; //   1Gb // page directory index
+		uint64_t pdpt   :  9; // 512Gb // page directory pointer table index
+		uint64_t pml4   :  9; // 256Tb // page map level 4 index
+		uint64_t sign   : 16;
+	} __attribute__((packed));
+};
+
+
+/* amd64/32/paging.c */
+extern pe_generic_t pml4_identity[512];
+void pml4_identity_init(void); // called from amd64/32/boot.s
-- 
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