Lab 2

Author: anishathalye

GNUmakefile

@@ -67,6 +67,7 @@ endif
 GDBPORT	:= $(shell expr `id -u` % 5000 + 25000)
 
 CC	:= $(GCCPREFIX)gcc -pipe
+GDB	:= $(GCCPREFIX)gdb
 AS	:= $(GCCPREFIX)as
 AR	:= $(GCCPREFIX)ar
 LD	:= $(GCCPREFIX)ld
@@ -148,7 +149,7 @@ QEMUOPTS += $(QEMUEXTRA)
 	sed "s/localhost:1234/localhost:$(GDBPORT)/" < $^ > $@
 
 gdb:
-	gdb -n -x .gdbinit
+	$(GDB) -n -x .gdbinit
 
 pre-qemu: .gdbinit
 

conf/lab.mk

@@ -1,2 +1,2 @@
-LAB=1
-PACKAGEDATE=Thu Aug 30 15:16:04 EDT 2018
+LAB=2
+PACKAGEDATE=Wed Sep 12 14:51:29 EDT 2018

grade-lab2

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+
+from gradelib import *
+
+r = Runner(save("jos.out"),
+           stop_breakpoint("readline"))
+
+@test(0, "running JOS")
+def test_jos():
+    r.run_qemu()
+
+@test(20, "Physical page allocator", parent=test_jos)
+def test_check_page_alloc():
+    r.match(r"check_page_alloc\(\) succeeded!")
+
+@test(20, "Page management", parent=test_jos)
+def test_check_page():
+    r.match(r"check_page\(\) succeeded!")
+
+@test(20, "Kernel page directory", parent=test_jos)
+def test_check_kern_pgdir():
+    r.match(r"check_kern_pgdir\(\) succeeded!")
+
+@test(10, "Page management 2", parent=test_jos)
+def test_check_page_installed_pgdir():
+    r.match(r"check_page_installed_pgdir\(\) succeeded!")
+
+run_tests()

inc/memlayout.h

@@ -143,5 +143,46 @@
 typedef uint32_t pte_t;
 typedef uint32_t pde_t;
 
+#if JOS_USER
+/*
+ * The page directory entry corresponding to the virtual address range
+ * [UVPT, UVPT + PTSIZE) points to the page directory itself.  Thus, the page
+ * directory is treated as a page table as well as a page directory.
+ *
+ * One result of treating the page directory as a page table is that all PTEs
+ * can be accessed through a "virtual page table" at virtual address UVPT (to
+ * which uvpt is set in lib/entry.S).  The PTE for page number N is stored in
+ * uvpt[N].  (It's worth drawing a diagram of this!)
+ *
+ * A second consequence is that the contents of the current page directory
+ * will always be available at virtual address (UVPT + (UVPT >> PGSHIFT)), to
+ * which uvpd is set in lib/entry.S.
+ */
+extern volatile pte_t uvpt[];     // VA of "virtual page table"
+extern volatile pde_t uvpd[];     // VA of current page directory
+#endif
+
+/*
+ * Page descriptor structures, mapped at UPAGES.
+ * Read/write to the kernel, read-only to user programs.
+ *
+ * Each struct PageInfo stores metadata for one physical page.
+ * Is it NOT the physical page itself, but there is a one-to-one
+ * correspondence between physical pages and struct PageInfo's.
+ * You can map a struct PageInfo * to the corresponding physical address
+ * with page2pa() in kern/pmap.h.
+ */
+struct PageInfo {
+	// Next page on the free list.
+	struct PageInfo *pp_link;
+
+	// pp_ref is the count of pointers (usually in page table entries)
+	// to this page, for pages allocated using page_alloc.
+	// Pages allocated at boot time using pmap.c's
+	// boot_alloc do not have valid reference count fields.
+
+	uint16_t pp_ref;
+};
+
 #endif /* !__ASSEMBLER__ */
 #endif /* !JOS_INC_MEMLAYOUT_H */

kern/init.c

@@ -6,18 +6,9 @@
 
 #include <kern/monitor.h>
 #include <kern/console.h>
+#include <kern/pmap.h>
+#include <kern/kclock.h>
 
-// Test the stack backtrace function (lab 1 only)
-void
-test_backtrace(int x)
-{
-	cprintf("entering test_backtrace %d\n", x);
-	if (x > 0)
-		test_backtrace(x-1);
-	else
-		mon_backtrace(0, 0, 0);
-	cprintf("leaving test_backtrace %d\n", x);
-}
 
 void
 i386_init(void)
@@ -35,8 +26,8 @@ i386_init(void)
 
 	cprintf("6828 decimal is %o octal!\n", 6828);
 
-	// Test the stack backtrace function (lab 1 only)
-	test_backtrace(5);
+	// Lab 2 memory management initialization functions
+	mem_init();
 
 	// Drop into the kernel monitor.
 	while (1)

kern/kclock.c

@@ -0,0 +1,22 @@
+/* See COPYRIGHT for copyright information. */
+
+/* Support for reading the NVRAM from the real-time clock. */
+
+#include <inc/x86.h>
+
+#include <kern/kclock.h>
+
+
+unsigned
+mc146818_read(unsigned reg)
+{
+	outb(IO_RTC, reg);
+	return inb(IO_RTC+1);
+}
+
+void
+mc146818_write(unsigned reg, unsigned datum)
+{
+	outb(IO_RTC, reg);
+	outb(IO_RTC+1, datum);
+}

kern/kclock.h

@@ -0,0 +1,29 @@
+/* See COPYRIGHT for copyright information. */
+
+#ifndef JOS_KERN_KCLOCK_H
+#define JOS_KERN_KCLOCK_H
+#ifndef JOS_KERNEL
+# error "This is a JOS kernel header; user programs should not #include it"
+#endif
+
+#define	IO_RTC		0x070		/* RTC port */
+
+#define	MC_NVRAM_START	0xe	/* start of NVRAM: offset 14 */
+#define	MC_NVRAM_SIZE	50	/* 50 bytes of NVRAM */
+
+/* NVRAM bytes 7 & 8: base memory size */
+#define NVRAM_BASELO	(MC_NVRAM_START + 7)	/* low byte; RTC off. 0x15 */
+#define NVRAM_BASEHI	(MC_NVRAM_START + 8)	/* high byte; RTC off. 0x16 */
+
+/* NVRAM bytes 9 & 10: extended memory size (between 1MB and 16MB) */
+#define NVRAM_EXTLO	(MC_NVRAM_START + 9)	/* low byte; RTC off. 0x17 */
+#define NVRAM_EXTHI	(MC_NVRAM_START + 10)	/* high byte; RTC off. 0x18 */
+
+/* NVRAM bytes 38 and 39: extended memory size (between 16MB and 4G) */
+#define NVRAM_EXT16LO	(MC_NVRAM_START + 38)	/* low byte; RTC off. 0x34 */
+#define NVRAM_EXT16HI	(MC_NVRAM_START + 39)	/* high byte; RTC off. 0x35 */
+
+unsigned mc146818_read(unsigned reg);
+void mc146818_write(unsigned reg, unsigned datum);
+
+#endif	// !JOS_KERN_KCLOCK_H

kern/pmap.c

@@ -0,0 +1,87 @@
+/* See COPYRIGHT for copyright information. */
+
+#ifndef JOS_KERN_PMAP_H
+#define JOS_KERN_PMAP_H
+#ifndef JOS_KERNEL
+# error "This is a JOS kernel header; user programs should not #include it"
+#endif
+
+#include <inc/memlayout.h>
+#include <inc/assert.h>
+
+extern char bootstacktop[], bootstack[];
+
+extern struct PageInfo *pages;
+extern size_t npages;
+
+extern pde_t *kern_pgdir;
+
+
+/* This macro takes a kernel virtual address -- an address that points above
+ * KERNBASE, where the machine's maximum 256MB of physical memory is mapped --
+ * and returns the corresponding physical address.  It panics if you pass it a
+ * non-kernel virtual address.
+ */
+#define PADDR(kva) _paddr(__FILE__, __LINE__, kva)
+
+static inline physaddr_t
+_paddr(const char *file, int line, void *kva)
+{
+	if ((uint32_t)kva < KERNBASE)
+		_panic(file, line, "PADDR called with invalid kva %08lx", kva);
+	return (physaddr_t)kva - KERNBASE;
+}
+
+/* This macro takes a physical address and returns the corresponding kernel
+ * virtual address.  It panics if you pass an invalid physical address. */
+#define KADDR(pa) _kaddr(__FILE__, __LINE__, pa)
+
+static inline void*
+_kaddr(const char *file, int line, physaddr_t pa)
+{
+	if (PGNUM(pa) >= npages)
+		_panic(file, line, "KADDR called with invalid pa %08lx", pa);
+	return (void *)(pa + KERNBASE);
+}
+
+
+enum {
+	// For page_alloc, zero the returned physical page.
+	ALLOC_ZERO = 1<<0,
+};
+
+void	mem_init(void);
+
+void	page_init(void);
+struct PageInfo *page_alloc(int alloc_flags);
+void	page_free(struct PageInfo *pp);
+int	page_insert(pde_t *pgdir, struct PageInfo *pp, void *va, int perm);
+void	page_remove(pde_t *pgdir, void *va);
+struct PageInfo *page_lookup(pde_t *pgdir, void *va, pte_t **pte_store);
+void	page_decref(struct PageInfo *pp);
+
+void	tlb_invalidate(pde_t *pgdir, void *va);
+
+static inline physaddr_t
+page2pa(struct PageInfo *pp)
+{
+	return (pp - pages) << PGSHIFT;
+}
+
+static inline struct PageInfo*
+pa2page(physaddr_t pa)
+{
+	if (PGNUM(pa) >= npages)
+		panic("pa2page called with invalid pa");
+	return &pages[PGNUM(pa)];
+}
+
+static inline void*
+page2kva(struct PageInfo *pp)
+{
+	return KADDR(page2pa(pp));
+}
+
+pte_t *pgdir_walk(pde_t *pgdir, const void *va, int create);
+
+#endif /* !JOS_KERN_PMAP_H */