Implement the showmappings command

kern/ansi.h

@@ -6,7 +6,7 @@
 #define ACOL_WRAP(s) "\33[" s "m"
 #define ACOL_BLACK  ACOL_WRAP("30")
 #define ACOL_RED ACOL_WRAP("31")
-#define ACOL_GREEM ACOL_WRAP("32")
+#define ACOL_GREEN ACOL_WRAP("32")
 #define ACOL_YELLOW ACOL_WRAP("33")
 #define ACOL_BLUE ACOL_WRAP("34")
 #define ACOL_MAGENTA ACOL_WRAP("35")

kern/monitor.c

@@ -7,9 +7,13 @@
 #include <inc/assert.h>
 #include <inc/x86.h>
 
+#include <kern/ansi.h>
 #include <kern/console.h>
 #include <kern/monitor.h>
 #include <kern/kdebug.h>
+#include <kern/pmap.h>
+
+#include <inc/string.h>
 
 #define CMDBUF_SIZE	80	// enough for one VGA text line
 
@@ -25,7 +29,8 @@ struct Command {
 static struct Command commands[] = {
 	{ "help", "Display this list of commands", mon_help },
 	{ "kerninfo", "Display information about the kernel", mon_kerninfo },
-	{ "backtrace", "Display current backtrace", mon_backtrace }
+	{ "backtrace", "Display current backtrace", mon_backtrace },
+	{ "showmappings", "Display the physical mappings for range", mon_showmappings }
 };
 
 /***** Implementations of basic kernel monitor commands *****/
@@ -84,6 +89,53 @@ mon_backtrace(int argc, char **argv, struct Trapframe *tf)
 	return 0;
 }
 
+#define EXPECT_ARGS(n, ac) if(ac - 1 != n) { \
+	cprintf(ACOL_ERR("Expected %d arguments, " \
+		"got %d\n"), n, ac - 1); \
+	return 1; }
+
+#define VA_TXT ACOL_CYAN "VA" ACOL_CLEAR
+#define PA_TXT ACOL_GREEN "PA" ACOL_CLEAR
+
+char*
+decode_pte_perms(pte_t pte, char* buffer) {
+	buffer[0] = (pte & PTE_W) ? 'w' : 'r';
+	buffer[1] = (pte & PTE_U) ? 'u' : 'k';
+	return buffer;
+}
+
+int
+mon_showmappings(int argc, char** argv, struct Trapframe* tf) {
+	EXPECT_ARGS(2, argc);
+	long from = strtol(argv[1], NULL, 0);
+	long to = strtol(argv[2], NULL, 0);
+
+	uintptr_t va_start = ROUNDDOWN(from, PGSIZE);
+	uintptr_t va_end = ROUNDUP(to, PGSIZE);
+	if(va_start != from) cprintf(ACOL_WARN("Aligning start address %p down to %p\n"),
+		from, va_start);
+	if(va_end != to) cprintf(ACOL_WARN("Aligning end address %p up to %p\n"),
+		to, va_end);
+
+	char buffer[3] = {0};
+
+	if(va_start == va_end) va_end += PGSIZE;
+	while(va_start < va_end) {
+		pte_t* pte = pgdir_walk(kern_pgdir, (const void*) va_start, 0);
+		cprintf(VA_TXT " 0x%08p -> ", va_start);
+
+		if(pte && (*pte & PTE_P)) {
+			cprintf(PA_TXT " 0x%08p (%s)\n", PTE_ADDR(*pte),
+				decode_pte_perms(*pte, buffer));
+		} else {
+			cprintf(PA_TXT " ------------\n");
+		}
+
+		va_start += PGSIZE;
+	}
+
+	return 0;
+}
 
 
 /***** Kernel monitor command interpreter *****/

kern/monitor.h

@@ -15,5 +15,6 @@ void monitor(struct Trapframe *tf);
 int mon_help(int argc, char **argv, struct Trapframe *tf);
 int mon_kerninfo(int argc, char **argv, struct Trapframe *tf);
 int mon_backtrace(int argc, char **argv, struct Trapframe *tf);
+int mon_showmappings(int argc, char **argv, struct Trapframe *tf);
 
 #endif	// !JOS_KERN_MONITOR_H