From 05c5b1361857e84ba1b94251b220cd3c5cfec90f Mon Sep 17 00:00:00 2001
From: Jacob Potter <jdpotter@andrew.cmu.edu>
Date: Thu, 25 Sep 2008 23:20:22 -0400
Subject: [PATCH] missing packet.[ch]

---
 aseg/packet.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++
 aseg/packet.h | 16 +++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 aseg/packet.c
 create mode 100644 aseg/packet.h

diff --git a/aseg/packet.c b/aseg/packet.c
new file mode 100644
index 0000000..ff5c41e
--- /dev/null
+++ b/aseg/packet.c
@@ -0,0 +1,77 @@
+#include <stdint.h>
+#include "packet.h"
+
+#define PTE_FOR(x)      (((unsigned int)(x) >> 12) & 0x3FF)
+#define PDE_FOR(x)      ((unsigned int)(x) >> 22)
+#define ADDR_12_MASK(x)	((unsigned int)(x) & ~((1 << 12) - 1))
+#define ADDR_22_MASK(x)	((unsigned int)(x) & ~((1 << 22) - 1))
+#define LOWER_12(x)	((unsigned int)(x) & ((1 << 12) - 1))
+#define LOWER_22(x)	((unsigned int)(x) & ((1 << 22) - 1))
+
+#define PDE_4M_ADDR_SHIFT       22
+#define PTE_4K_ADDR_SHIFT       12
+#define PDE_TABLE_ADDR_SHIFT    12
+#define PTE_FRAME_ADDR_MASK     (~((1 << PTE_4K_ADDR_SHIFT) - 1))
+#define PDE_TABLE_ADDR_MASK     (~((1 << PDE_TABLE_ADDR_SHIFT) - 1))
+
+#define PDE_ATTRIB_INDEX        (1 << 12)
+#define PDE_GLOBAL              (1 << 8)
+#define PDE_PAGE_SIZE           (1 << 7)
+#define PDE_DIRTY               (1 << 6)
+#define PDE_ACCESSED            (1 << 5)
+#define PDE_NO_CACHE            (1 << 4)
+#define PDE_WRITE_THROUGH       (1 << 3)
+#define PDE_USER                (1 << 2)
+#define PDE_READ_WRITE          (1 << 1)
+#define PDE_PRESENT             (1 << 0)
+
+#define PTE_GLOBAL              (1 << 8)
+#define PTE_ATTRIB_INDEX        (1 << 7)
+#define PTE_DIRTY               (1 << 6)
+#define PTE_ACCESSED            (1 << 5)
+#define PTE_NO_CACHE            (1 << 4)
+#define PTE_WRITE_THROUGH       (1 << 3)
+#define PTE_USER                (1 << 2)
+#define PTE_READ_WRITE          (1 << 1)
+#define PTE_PRESENT             (1 << 0)
+
+asm ("get_cr3: mov %cr3, %eax \n ret");
+uint32_t * get_cr3();
+
+void * l2p (void * addr) {
+
+	uint32_t * cr3 = get_cr3();
+	uint32_t * page_table;
+	uint32_t pde, pte;
+
+	pde = cr3[PDE_FOR(addr)];
+
+	if (!(pde & PDE_PRESENT)) {
+		return 0;
+	}
+
+	if (pde & PDE_PAGE_SIZE) {
+		return (void *)(ADDR_22_MASK(pde) | LOWER_22(addr));
+	} else {
+		page_table = (uint32_t *)(ADDR_12_MASK(pde));
+		pte = page_table[PTE_FOR(addr)];
+
+		if (!pte & PTE_PRESENT) {
+			return 0;
+		}
+		return (void *)(ADDR_12_MASK(pte) | LOWER_12(addr));
+	}
+}
+
+packet_t * check_packet (uint32_t logical_base) {
+	packet_t * physical_base;
+
+	if (LOWER_12(logical_base) != 0) return 0;
+
+	physical_base = l2p((void *)logical_base);
+
+	if (!physical_base) return 0;
+	if (physical_base->signature != 0x1BADD00D) return 0;
+	
+	return physical_base;
+}
diff --git a/aseg/packet.h b/aseg/packet.h
new file mode 100644
index 0000000..1544f04
--- /dev/null
+++ b/aseg/packet.h
@@ -0,0 +1,16 @@
+#ifndef _PAGETABLE_H
+#define _PAGETABLE_H
+
+#include <stdint.h>
+
+void * l2p(void * addr);
+
+typedef struct {
+	uint32_t signature;
+	uint32_t type;
+	uint8_t data[];
+} packet_t;
+
+packet_t * check_packet(uint32_t logical_addr);
+
+#endif /* _PAGETABLE_H */
-- 
2.39.2