allocate all kernel page directories at boot, this will simplify later code a lot.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26721 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/platform/atari_m68k/mmu.cpp

@@ -270,8 +270,12 @@ init_page_directory(void)
 
 	// set the root pointers
 	gMMUOps->load_rp(gPageRoot);
+	// allocate second level tables for kernel space
+	// this will simplify mmu code a lot, and only wastes 32KB
+	gMMUOps->allocate_kernel_pgdirs();
 	// enable mmu translation
 	gMMUOps->enable_paging();
+	//XXX: check for errors
 
 	//gKernelArgs.arch_args.num_pgtables = 0;
 	gMMUOps->add_page_table(KERNEL_BASE);

src/system/boot/platform/atari_m68k/mmu.h

@@ -31,6 +31,7 @@ struct boot_mmu_ops {
 	status_t (*set_tt)(int which, addr_t pa, size_t len, uint32 perms);
 		/* load root pointers */
 	status_t (*load_rp)(addr_t pa);
+	status_t (*allocate_kernel_pgdirs)(void);
 	status_t (*enable_paging)(void);
 	status_t (*add_page_table)(addr_t virtualAddress);
 	void (*unmap_page)(addr_t virtualAddress);

src/system/boot/platform/atari_m68k/mmu_030.cpp

@@ -103,6 +103,30 @@ load_rp(addr_t pa)
 }
 
 
+static status_t
+allocate_kernel_pgdirs(void)
+{
+	page_root_entry *pr = gPageRoot;
+	page_directory_entry *pd;
+	addr_t tbl;
+	int i;
+
+	// we'll fill in the 2nd half with ready made page dirs
+	for (i = NUM_ROOTENT_PER_TBL/2; i < NUM_ROOTENT_PER_TBL; i++) {
+		if (i % NUM_DIRTBL_PER_PAGE)
+			tbl += SIZ_DIRTBL;
+		else
+			tbl = mmu_get_next_page_tables();
+		pr[i].addr = TA_TO_PREA(tbl);
+		pr[i].type = DT_ROOT;
+		pd = (page_directory_entry *)tbl;
+		for (int32 j = 0; j < NUM_DIRENT_PER_TBL; j++)
+			*(page_directory_entry_scalar *)(&pd[j]) = DFL_DIRENT_VAL;
+	}
+	return B_OK;
+}
+
+
 static status_t
 enable_paging(void)
 {
@@ -115,5 +139,6 @@ const struct boot_mmu_ops k030MMUOps = {
 	&initialize,
 	&set_tt,
 	&load_rp,
+	&allocate_kernel_pgdirs,
 	&enable_paging
 };

src/system/boot/platform/atari_m68k/mmu_040.cpp

@@ -107,6 +107,30 @@ load_rp(addr_t pa)
 }
 
 
+static status_t
+allocate_kernel_pgdirs(void)
+{
+	page_root_entry *pr = gPageRoot;
+	page_directory_entry *pd;
+	addr_t tbl;
+	int i;
+
+	// we'll fill in the 2nd half with ready made page dirs
+	for (i = NUM_ROOTENT_PER_TBL/2; i < NUM_ROOTENT_PER_TBL; i++) {
+		if (i % NUM_DIRTBL_PER_PAGE)
+			tbl += SIZ_DIRTBL;
+		else
+			tbl = mmu_get_next_page_tables();
+		pr[i].addr = TA_TO_PREA(tbl);
+		pr[i].type = DT_ROOT;
+		pd = (page_directory_entry *)tbl;
+		for (int32 j = 0; j < NUM_DIRENT_PER_TBL; j++)
+			*(page_directory_entry_scalar *)(&pd[j]) = DFL_DIRENT_VAL;
+	}
+	return B_OK;
+}
+
+
 static status_t
 enable_paging(void)
 {
@@ -137,6 +161,10 @@ add_page_table(addr_t virtualAddress)
 	// thanks to transparent translation
 
 	index = VADDR_TO_PRENT(virtualAddress);
+	if (pr[index].type != DT_ROOT)
+		panic("invalid page root entry %d\n", index);
+#if 0
+	// not needed anymore
 	if (pr[index].type != DT_ROOT) {
 		unsigned aindex = index & ~(NUM_DIRTBL_PER_PAGE-1); /* aligned */
 		//TRACE(("missing page root entry %d ai %d\n", index, aindex));
@@ -157,6 +185,7 @@ add_page_table(addr_t virtualAddress)
 			tbl += SIZ_DIRTBL;
 		}
 	}
+#endif
 	pd = (page_directory_entry *)PRE_TO_TA(pr[index]);
 
 	index = VADDR_TO_PDENT(virtualAddress);
@@ -290,6 +319,7 @@ const struct boot_mmu_ops k040MMUOps = {
 	&initialize,
 	&set_tt,
 	&load_rp,
+	&allocate_kernel_pgdirs,
 	&enable_paging,
 	&add_page_table,
 	&unmap_page,