Patch set updated for coreboot: b0a1090 Enable pages. Tested and working on QEMU.

[Ronald G. Minnich]

Ronald G. Minnich ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5354

-gerrit

commit b0a109051c4c047c2c7e9911d6f6dcb4d82a1640
Author: Ronald G. Minnich <[e-mail]>
Date:   Sat Mar 8 17:33:12 2014 +0100

    Enable pages. Tested and working on QEMU.
    
    Enable page tables in coreboot. We're going to have to do this at some point,
    when we hit x86_64; the ARM ports do paging in both 32- and 64-bit modes;
    MTRR is a PITA; and it's easy. The non-paging architectures are outnumbered
    by the paging architectures!
    
    This trial example just sets up a 4G identity map using 4M pages.
    It works for QEMU just fine to boot tinycore linux.
    The next step is to map the low 4M much more finely, with 4K pages,
    so we can catch NULL pointers. This will require reworking VGA bios
    support, which uses page 0.
    
    For SMP, we'll need to add code to let them also load page tables,
    but one thing at a time.
    
    Next I'll add code to support page table manipulation. With luck,
    we can stop fighting the MTRRs with all their pain and suffering.
    We can use the MTRRs for very coarse mappings and use the page
    tables to refine them. For example, we could stop using fixed MTRRs
    entirely since we can map parts of the low 1M as WP or even UC on a 4k
    granularity.
    
    For now we use this for machines where coreboot can live in the low 4G.
    For other cases, it's time to start thinking about 64-bit mode; since
    entering Long Mode requires page tables, we need to figure it out. The
    ARM V8 port is carving the way so this is as good a time as any.
    
    This code is enabled by CONFIG_PGE, which defaults to n.
    To turn it on navigate to architecture options in
    menuconfig.
    
    A remaining question is whether to turn off paging when we start the payload.
    For now, we turn it off. Also, if they payload returns, we hang until such time
    as we turn paging back on (which is easy, actually).
    
    Change-Id: Iea0192e5187c47e63d25f88eaa3e88cb6c58feb1
    Signed-off-by: Ronald G. Minnich <[e-mail]>
---
 src/arch/x86/Kconfig                   |  11 ++
 src/arch/x86/Makefile.inc              |   3 +
 src/arch/x86/boot/boot.c               |  20 +++
 src/arch/x86/init/ldscript_failover.lb |   2 +-
 src/arch/x86/lib/c_start.S             |   5 +-
 src/arch/x86/lib/makepg.c              |  43 ++++++
 src/arch/x86/lib/pagetables.S          | 244 +++++++++++++++++++++++++++++++++
 src/arch/x86/lib/paging.S              |  58 ++++++++
 8 files changed, 384 insertions(+), 2 deletions(-)

diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig
index 8854e6b..0c0f91c 100644
--- a/src/arch/x86/Kconfig
+++ b/src/arch/x86/Kconfig
@@ -78,6 +78,17 @@ config UPDATE_IMAGE
 	  is a suitable file for further processing.
 	  The bootblock will not be modified.
 
+config PGE
+	bool "Enable x86 page tables."
+	default n
+	help
+	  In original coreboot we did not use page tables. The
+	  MTRR code just keeps getting messier and if we turn
+	  on paging it gets very easy. We can enable disable
+	  caching on anything down to a 4k boundary. We can
+	  control cache disable and write-back/writethrough
+	  on each page. For now, this code creates an identity
+	  map for 4G using 4M pages.
 config ROMCC
 	bool
 	default n
diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
index acb4e98..f004be8 100644
--- a/src/arch/x86/Makefile.inc
+++ b/src/arch/x86/Makefile.inc
@@ -354,6 +354,9 @@ bootblock_inc = $(src)/arch/x86/init/prologue.inc
 bootblock_inc += $(src)/cpu/x86/16bit/entry16.inc
 bootblock_inc += $(src)/cpu/x86/16bit/reset16.inc
 bootblock_inc += $(src)/cpu/x86/32bit/entry32.inc
+ifeq ($(CONFIG_PGE),y)
+bootblock_inc += $(src)/arch/x86/lib/paging.S
+endif
 bootblock_inc += $(src)/arch/x86/lib/id.inc
 ifeq ($(CONFIG_CPU_INTEL_FIRMWARE_INTERFACE_TABLE),y)
 bootblock_inc += $(src)/cpu/intel/fit/fit.inc
diff --git a/src/arch/x86/boot/boot.c b/src/arch/x86/boot/boot.c
index 29070a0..ca8af27 100644
--- a/src/arch/x86/boot/boot.c
+++ b/src/arch/x86/boot/boot.c
@@ -11,6 +11,12 @@ static void jmp_payload_no_bounce_buffer(void *entry)
 	/* Jump to kernel */
 	__asm__ __volatile__(
 		"	cld	\n\t"
+		/* Paging might have been on. We need to turn it off
+		 * right before we jump
+		 */
+		"	movl	%%cr0, %%eax\n\t"
+		"	andl	$0x7fffffff, %%eax\n\t"
+		"	movl	%%edx, %%cr0\n\t"
 		/* Now jump to the loaded image */
 		"	call	*%0\n\t"
 
@@ -73,6 +79,16 @@ static void jmp_payload(void *entry, unsigned long buffer, unsigned long size)
 		"	jmp	*%%eax\n\t"
 		"1:	\n\t"
 
+		/* Paging might have been on. It's ok,
+		 * the bounce buffer runs at same VA and PA.
+		 * So we can turn paging off now.
+		 */
+		"	movl	%%cr0, %%eax\n\t"
+		"	andl	$0x7fffffff, %%eax\n\t"
+		"	movl	%%eax, %%cr0\n\t"
+		"	jmp 1f\n\t"
+		"1:\n\t"
+
 		/* Copy the coreboot bounce buffer over coreboot */
 		/* Move ``longs'' the coreboot size is 4 byte aligned */
 		"	movl	16(%%esp), %%edi\n\t"
@@ -85,6 +101,10 @@ static void jmp_payload(void *entry, unsigned long buffer, unsigned long size)
 		"	movl	%5, %%eax\n\t"
 		"	movl	 0(%%esp), %%ebx\n\t"
 		"	call	*4(%%esp)\n\t"
+#if CONFIG_PGE
+		/* TODO: turn paging back on. For now, just hang. */
+		"1: jmp 1b\n\t"
+#endif
 
 		/* The loaded image returned? */
 		"	cli	\n\t"
diff --git a/src/arch/x86/init/ldscript_failover.lb b/src/arch/x86/init/ldscript_failover.lb
index 318f429..4d24e73 100644
--- a/src/arch/x86/init/ldscript_failover.lb
+++ b/src/arch/x86/init/ldscript_failover.lb
@@ -54,7 +54,7 @@ SECTIONS
 	 * address gets applied.
 	 */
 	ROMLOC_MIN = 0xffffff00 - (_erom - _rom + 16) -
-		(CONFIG_SIPI_VECTOR_IN_ROM ? 4096 : 0);
+		(CONFIG_SIPI_VECTOR_IN_ROM ? 4096 : 0) - 8192;
 
 	/* Post-check proper SIPI vector. */
 	_bogus = ASSERT(!CONFIG_SIPI_VECTOR_IN_ROM || ((ap_sipi_vector & 0x0fff) == 0x0),
diff --git a/src/arch/x86/lib/c_start.S b/src/arch/x86/lib/c_start.S
index faea22d..bbf3308 100644
--- a/src/arch/x86/lib/c_start.S
+++ b/src/arch/x86/lib/c_start.S
@@ -33,7 +33,10 @@ _start:
 	movl	%eax, %gs
 
 	post_code(POST_ENTRY_C_START)		/* post 13 */
-
+	/* turn on paging (conditional on CONFIG_PGE) */
+#if CONFIG_PGE
+#include "paging.S"
+#endif
 	cld
 
 	/** poison the stack. Code should not count on the
diff --git a/src/arch/x86/lib/makepg.c b/src/arch/x86/lib/makepg.c
new file mode 100644
index 0000000..d32e616
--- /dev/null
+++ b/src/arch/x86/lib/makepg.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+main(int argc, char *argv[])
+{
+	int i, j;
+	printf(".align 4096\npml0:");
+/*
+	for(i = 0; i < 1024; i += 8){
+		printf("\t.long ");
+		for(j = 0; j < 8; j++){
+			if (!i && !j)
+				printf("0x%08x,", 0);
+			else
+				printf("0x%08x%s", ((i+j)<<12) + 0x5, j < 7 ? ",":"");
+		}
+		printf("\n");
+	}
+	printf("pml1:\n");
+	for(i = 0; i < 1024; i += 8){
+		printf("\t.long ");
+		for(j = 0; j < 8; j++)
+			if (!i && !j)
+				printf("pml0+5,");
+			else
+				printf("0x%08x%s", ((i+j)<<22) + 0x85,j < 7 ? ",":"");
+		printf("\n");
+	}
+*/
+	for(i = 0; i < 1024; i += 8){
+		printf("\t.long ");
+		for(j = 0; j < 8; j++)
+			printf("P4M(0x%03x)%s", (i+j), j < 7 ? ",":"");
+		printf("\n");
+	}
+	/* 64-bit paging. First, a page of 2M pages, then the next two levels after
+	 * that
+	 */
+	for(i = 0; i < 512; i += 8){
+		printf("\t.quad ");
+		for(j = 0; j < 8; j++)
+			printf("P2M(0x%03x)%s", (i+j), j < 7 ? ",":"");
+		printf("\n");
+	}
+}
diff --git a/src/arch/x86/lib/pagetables.S b/src/arch/x86/lib/pagetables.S
new file mode 100644
index 0000000..e87c1bf
--- /dev/null
+++ b/src/arch/x86/lib/pagetables.S
@@ -0,0 +1,244 @@
+	.long 1
+	.align 4096
+
+/* Create a PTE given an address. It's your responsibility to make
+ * sure the address meets all requirements, viz., low order 12 bits
+ * are zero. The PTE will have the Present (1) and Write (4) bits set.
+ */
+#define PTE(x) ((x)|5)
+/* Create an entry for a 4K page, with Present bit (1) and Write bit (4) set
+ * The parameter is a page number, not an address. For 32-bit mode, use .long;
+ * for 64-bit mode, use .llong
+ */
+#define P4K(x) ((x<<12)|5)
+
+/* Create an entry for a 32-bit 4M page, with Page Size (0x80), Present bit
+ * (1) and Write bit (4) set The parameter is a 4M page number, not an
+ * address.
+ */
+#define P4M(x) ((x<<22) | 0x80 | 5)
+
+/* Create an entry for a 64-bit 2M page, with Page Size (0x80),
+ * Present bit (1) and Write bit (4) set The parameter is a page
+ * number, not an address.
+ */
+#define P2M(x) ((x<<21) | 0x80 | 5)
+
+/* Define a Page Map Level 2 of 4M entries to identity-map
+ * the low 4G of memory. This is just enough to get us into
+ * Long Mode.
+ */
+PageMapLevel2:
+	.long P4M(0x000),P4M(0x001),P4M(0x002),P4M(0x003),P4M(0x004),P4M(0x005),P4M(0x006),P4M(0x007)
+	.long P4M(0x008),P4M(0x009),P4M(0x00a),P4M(0x00b),P4M(0x00c),P4M(0x00d),P4M(0x00e),P4M(0x00f)
+	.long P4M(0x010),P4M(0x011),P4M(0x012),P4M(0x013),P4M(0x014),P4M(0x015),P4M(0x016),P4M(0x017)
+	.long P4M(0x018),P4M(0x019),P4M(0x01a),P4M(0x01b),P4M(0x01c),P4M(0x01d),P4M(0x01e),P4M(0x01f)
+	.long P4M(0x020),P4M(0x021),P4M(0x022),P4M(0x023),P4M(0x024),P4M(0x025),P4M(0x026),P4M(0x027)
+	.long P4M(0x028),P4M(0x029),P4M(0x02a),P4M(0x02b),P4M(0x02c),P4M(0x02d),P4M(0x02e),P4M(0x02f)
+	.long P4M(0x030),P4M(0x031),P4M(0x032),P4M(0x033),P4M(0x034),P4M(0x035),P4M(0x036),P4M(0x037)
+	.long P4M(0x038),P4M(0x039),P4M(0x03a),P4M(0x03b),P4M(0x03c),P4M(0x03d),P4M(0x03e),P4M(0x03f)
+	.long P4M(0x040),P4M(0x041),P4M(0x042),P4M(0x043),P4M(0x044),P4M(0x045),P4M(0x046),P4M(0x047)
+	.long P4M(0x048),P4M(0x049),P4M(0x04a),P4M(0x04b),P4M(0x04c),P4M(0x04d),P4M(0x04e),P4M(0x04f)
+	.long P4M(0x050),P4M(0x051),P4M(0x052),P4M(0x053),P4M(0x054),P4M(0x055),P4M(0x056),P4M(0x057)
+	.long P4M(0x058),P4M(0x059),P4M(0x05a),P4M(0x05b),P4M(0x05c),P4M(0x05d),P4M(0x05e),P4M(0x05f)
+	.long P4M(0x060),P4M(0x061),P4M(0x062),P4M(0x063),P4M(0x064),P4M(0x065),P4M(0x066),P4M(0x067)
+	.long P4M(0x068),P4M(0x069),P4M(0x06a),P4M(0x06b),P4M(0x06c),P4M(0x06d),P4M(0x06e),P4M(0x06f)
+	.long P4M(0x070),P4M(0x071),P4M(0x072),P4M(0x073),P4M(0x074),P4M(0x075),P4M(0x076),P4M(0x077)
+	.long P4M(0x078),P4M(0x079),P4M(0x07a),P4M(0x07b),P4M(0x07c),P4M(0x07d),P4M(0x07e),P4M(0x07f)
+	.long P4M(0x080),P4M(0x081),P4M(0x082),P4M(0x083),P4M(0x084),P4M(0x085),P4M(0x086),P4M(0x087)
+	.long P4M(0x088),P4M(0x089),P4M(0x08a),P4M(0x08b),P4M(0x08c),P4M(0x08d),P4M(0x08e),P4M(0x08f)
+	.long P4M(0x090),P4M(0x091),P4M(0x092),P4M(0x093),P4M(0x094),P4M(0x095),P4M(0x096),P4M(0x097)
+	.long P4M(0x098),P4M(0x099),P4M(0x09a),P4M(0x09b),P4M(0x09c),P4M(0x09d),P4M(0x09e),P4M(0x09f)
+	.long P4M(0x0a0),P4M(0x0a1),P4M(0x0a2),P4M(0x0a3),P4M(0x0a4),P4M(0x0a5),P4M(0x0a6),P4M(0x0a7)
+	.long P4M(0x0a8),P4M(0x0a9),P4M(0x0aa),P4M(0x0ab),P4M(0x0ac),P4M(0x0ad),P4M(0x0ae),P4M(0x0af)
+	.long P4M(0x0b0),P4M(0x0b1),P4M(0x0b2),P4M(0x0b3),P4M(0x0b4),P4M(0x0b5),P4M(0x0b6),P4M(0x0b7)
+	.long P4M(0x0b8),P4M(0x0b9),P4M(0x0ba),P4M(0x0bb),P4M(0x0bc),P4M(0x0bd),P4M(0x0be),P4M(0x0bf)
+	.long P4M(0x0c0),P4M(0x0c1),P4M(0x0c2),P4M(0x0c3),P4M(0x0c4),P4M(0x0c5),P4M(0x0c6),P4M(0x0c7)
+	.long P4M(0x0c8),P4M(0x0c9),P4M(0x0ca),P4M(0x0cb),P4M(0x0cc),P4M(0x0cd),P4M(0x0ce),P4M(0x0cf)
+	.long P4M(0x0d0),P4M(0x0d1),P4M(0x0d2),P4M(0x0d3),P4M(0x0d4),P4M(0x0d5),P4M(0x0d6),P4M(0x0d7)
+	.long P4M(0x0d8),P4M(0x0d9),P4M(0x0da),P4M(0x0db),P4M(0x0dc),P4M(0x0dd),P4M(0x0de),P4M(0x0df)
+	.long P4M(0x0e0),P4M(0x0e1),P4M(0x0e2),P4M(0x0e3),P4M(0x0e4),P4M(0x0e5),P4M(0x0e6),P4M(0x0e7)
+	.long P4M(0x0e8),P4M(0x0e9),P4M(0x0ea),P4M(0x0eb),P4M(0x0ec),P4M(0x0ed),P4M(0x0ee),P4M(0x0ef)
+	.long P4M(0x0f0),P4M(0x0f1),P4M(0x0f2),P4M(0x0f3),P4M(0x0f4),P4M(0x0f5),P4M(0x0f6),P4M(0x0f7)
+	.long P4M(0x0f8),P4M(0x0f9),P4M(0x0fa),P4M(0x0fb),P4M(0x0fc),P4M(0x0fd),P4M(0x0fe),P4M(0x0ff)
+	.long P4M(0x100),P4M(0x101),P4M(0x102),P4M(0x103),P4M(0x104),P4M(0x105),P4M(0x106),P4M(0x107)
+	.long P4M(0x108),P4M(0x109),P4M(0x10a),P4M(0x10b),P4M(0x10c),P4M(0x10d),P4M(0x10e),P4M(0x10f)
+	.long P4M(0x110),P4M(0x111),P4M(0x112),P4M(0x113),P4M(0x114),P4M(0x115),P4M(0x116),P4M(0x117)
+	.long P4M(0x118),P4M(0x119),P4M(0x11a),P4M(0x11b),P4M(0x11c),P4M(0x11d),P4M(0x11e),P4M(0x11f)
+	.long P4M(0x120),P4M(0x121),P4M(0x122),P4M(0x123),P4M(0x124),P4M(0x125),P4M(0x126),P4M(0x127)
+	.long P4M(0x128),P4M(0x129),P4M(0x12a),P4M(0x12b),P4M(0x12c),P4M(0x12d),P4M(0x12e),P4M(0x12f)
+	.long P4M(0x130),P4M(0x131),P4M(0x132),P4M(0x133),P4M(0x134),P4M(0x135),P4M(0x136),P4M(0x137)
+	.long P4M(0x138),P4M(0x139),P4M(0x13a),P4M(0x13b),P4M(0x13c),P4M(0x13d),P4M(0x13e),P4M(0x13f)
+	.long P4M(0x140),P4M(0x141),P4M(0x142),P4M(0x143),P4M(0x144),P4M(0x145),P4M(0x146),P4M(0x147)
+	.long P4M(0x148),P4M(0x149),P4M(0x14a),P4M(0x14b),P4M(0x14c),P4M(0x14d),P4M(0x14e),P4M(0x14f)
+	.long P4M(0x150),P4M(0x151),P4M(0x152),P4M(0x153),P4M(0x154),P4M(0x155),P4M(0x156),P4M(0x157)
+	.long P4M(0x158),P4M(0x159),P4M(0x15a),P4M(0x15b),P4M(0x15c),P4M(0x15d),P4M(0x15e),P4M(0x15f)
+	.long P4M(0x160),P4M(0x161),P4M(0x162),P4M(0x163),P4M(0x164),P4M(0x165),P4M(0x166),P4M(0x167)
+	.long P4M(0x168),P4M(0x169),P4M(0x16a),P4M(0x16b),P4M(0x16c),P4M(0x16d),P4M(0x16e),P4M(0x16f)
+	.long P4M(0x170),P4M(0x171),P4M(0x172),P4M(0x173),P4M(0x174),P4M(0x175),P4M(0x176),P4M(0x177)
+	.long P4M(0x178),P4M(0x179),P4M(0x17a),P4M(0x17b),P4M(0x17c),P4M(0x17d),P4M(0x17e),P4M(0x17f)
+	.long P4M(0x180),P4M(0x181),P4M(0x182),P4M(0x183),P4M(0x184),P4M(0x185),P4M(0x186),P4M(0x187)
+	.long P4M(0x188),P4M(0x189),P4M(0x18a),P4M(0x18b),P4M(0x18c),P4M(0x18d),P4M(0x18e),P4M(0x18f)
+	.long P4M(0x190),P4M(0x191),P4M(0x192),P4M(0x193),P4M(0x194),P4M(0x195),P4M(0x196),P4M(0x197)
+	.long P4M(0x198),P4M(0x199),P4M(0x19a),P4M(0x19b),P4M(0x19c),P4M(0x19d),P4M(0x19e),P4M(0x19f)
+	.long P4M(0x1a0),P4M(0x1a1),P4M(0x1a2),P4M(0x1a3),P4M(0x1a4),P4M(0x1a5),P4M(0x1a6),P4M(0x1a7)
+	.long P4M(0x1a8),P4M(0x1a9),P4M(0x1aa),P4M(0x1ab),P4M(0x1ac),P4M(0x1ad),P4M(0x1ae),P4M(0x1af)
+	.long P4M(0x1b0),P4M(0x1b1),P4M(0x1b2),P4M(0x1b3),P4M(0x1b4),P4M(0x1b5),P4M(0x1b6),P4M(0x1b7)
+	.long P4M(0x1b8),P4M(0x1b9),P4M(0x1ba),P4M(0x1bb),P4M(0x1bc),P4M(0x1bd),P4M(0x1be),P4M(0x1bf)
+	.long P4M(0x1c0),P4M(0x1c1),P4M(0x1c2),P4M(0x1c3),P4M(0x1c4),P4M(0x1c5),P4M(0x1c6),P4M(0x1c7)
+	.long P4M(0x1c8),P4M(0x1c9),P4M(0x1ca),P4M(0x1cb),P4M(0x1cc),P4M(0x1cd),P4M(0x1ce),P4M(0x1cf)
+	.long P4M(0x1d0),P4M(0x1d1),P4M(0x1d2),P4M(0x1d3),P4M(0x1d4),P4M(0x1d5),P4M(0x1d6),P4M(0x1d7)
+	.long P4M(0x1d8),P4M(0x1d9),P4M(0x1da),P4M(0x1db),P4M(0x1dc),P4M(0x1dd),P4M(0x1de),P4M(0x1df)
+	.long P4M(0x1e0),P4M(0x1e1),P4M(0x1e2),P4M(0x1e3),P4M(0x1e4),P4M(0x1e5),P4M(0x1e6),P4M(0x1e7)
+	.long P4M(0x1e8),P4M(0x1e9),P4M(0x1ea),P4M(0x1eb),P4M(0x1ec),P4M(0x1ed),P4M(0x1ee),P4M(0x1ef)
+	.long P4M(0x1f0),P4M(0x1f1),P4M(0x1f2),P4M(0x1f3),P4M(0x1f4),P4M(0x1f5),P4M(0x1f6),P4M(0x1f7)
+	.long P4M(0x1f8),P4M(0x1f9),P4M(0x1fa),P4M(0x1fb),P4M(0x1fc),P4M(0x1fd),P4M(0x1fe),P4M(0x1ff)
+	.long P4M(0x200),P4M(0x201),P4M(0x202),P4M(0x203),P4M(0x204),P4M(0x205),P4M(0x206),P4M(0x207)
+	.long P4M(0x208),P4M(0x209),P4M(0x20a),P4M(0x20b),P4M(0x20c),P4M(0x20d),P4M(0x20e),P4M(0x20f)
+	.long P4M(0x210),P4M(0x211),P4M(0x212),P4M(0x213),P4M(0x214),P4M(0x215),P4M(0x216),P4M(0x217)
+	.long P4M(0x218),P4M(0x219),P4M(0x21a),P4M(0x21b),P4M(0x21c),P4M(0x21d),P4M(0x21e),P4M(0x21f)
+	.long P4M(0x220),P4M(0x221),P4M(0x222),P4M(0x223),P4M(0x224),P4M(0x225),P4M(0x226),P4M(0x227)
+	.long P4M(0x228),P4M(0x229),P4M(0x22a),P4M(0x22b),P4M(0x22c),P4M(0x22d),P4M(0x22e),P4M(0x22f)
+	.long P4M(0x230),P4M(0x231),P4M(0x232),P4M(0x233),P4M(0x234),P4M(0x235),P4M(0x236),P4M(0x237)
+	.long P4M(0x238),P4M(0x239),P4M(0x23a),P4M(0x23b),P4M(0x23c),P4M(0x23d),P4M(0x23e),P4M(0x23f)
+	.long P4M(0x240),P4M(0x241),P4M(0x242),P4M(0x243),P4M(0x244),P4M(0x245),P4M(0x246),P4M(0x247)
+	.long P4M(0x248),P4M(0x249),P4M(0x24a),P4M(0x24b),P4M(0x24c),P4M(0x24d),P4M(0x24e),P4M(0x24f)
+	.long P4M(0x250),P4M(0x251),P4M(0x252),P4M(0x253),P4M(0x254),P4M(0x255),P4M(0x256),P4M(0x257)
+	.long P4M(0x258),P4M(0x259),P4M(0x25a),P4M(0x25b),P4M(0x25c),P4M(0x25d),P4M(0x25e),P4M(0x25f)
+	.long P4M(0x260),P4M(0x261),P4M(0x262),P4M(0x263),P4M(0x264),P4M(0x265),P4M(0x266),P4M(0x267)
+	.long P4M(0x268),P4M(0x269),P4M(0x26a),P4M(0x26b),P4M(0x26c),P4M(0x26d),P4M(0x26e),P4M(0x26f)
+	.long P4M(0x270),P4M(0x271),P4M(0x272),P4M(0x273),P4M(0x274),P4M(0x275),P4M(0x276),P4M(0x277)
+	.long P4M(0x278),P4M(0x279),P4M(0x27a),P4M(0x27b),P4M(0x27c),P4M(0x27d),P4M(0x27e),P4M(0x27f)
+	.long P4M(0x280),P4M(0x281),P4M(0x282),P4M(0x283),P4M(0x284),P4M(0x285),P4M(0x286),P4M(0x287)
+	.long P4M(0x288),P4M(0x289),P4M(0x28a),P4M(0x28b),P4M(0x28c),P4M(0x28d),P4M(0x28e),P4M(0x28f)
+	.long P4M(0x290),P4M(0x291),P4M(0x292),P4M(0x293),P4M(0x294),P4M(0x295),P4M(0x296),P4M(0x297)
+	.long P4M(0x298),P4M(0x299),P4M(0x29a),P4M(0x29b),P4M(0x29c),P4M(0x29d),P4M(0x29e),P4M(0x29f)
+	.long P4M(0x2a0),P4M(0x2a1),P4M(0x2a2),P4M(0x2a3),P4M(0x2a4),P4M(0x2a5),P4M(0x2a6),P4M(0x2a7)
+	.long P4M(0x2a8),P4M(0x2a9),P4M(0x2aa),P4M(0x2ab),P4M(0x2ac),P4M(0x2ad),P4M(0x2ae),P4M(0x2af)
+	.long P4M(0x2b0),P4M(0x2b1),P4M(0x2b2),P4M(0x2b3),P4M(0x2b4),P4M(0x2b5),P4M(0x2b6),P4M(0x2b7)
+	.long P4M(0x2b8),P4M(0x2b9),P4M(0x2ba),P4M(0x2bb),P4M(0x2bc),P4M(0x2bd),P4M(0x2be),P4M(0x2bf)
+	.long P4M(0x2c0),P4M(0x2c1),P4M(0x2c2),P4M(0x2c3),P4M(0x2c4),P4M(0x2c5),P4M(0x2c6),P4M(0x2c7)
+	.long P4M(0x2c8),P4M(0x2c9),P4M(0x2ca),P4M(0x2cb),P4M(0x2cc),P4M(0x2cd),P4M(0x2ce),P4M(0x2cf)
+	.long P4M(0x2d0),P4M(0x2d1),P4M(0x2d2),P4M(0x2d3),P4M(0x2d4),P4M(0x2d5),P4M(0x2d6),P4M(0x2d7)
+	.long P4M(0x2d8),P4M(0x2d9),P4M(0x2da),P4M(0x2db),P4M(0x2dc),P4M(0x2dd),P4M(0x2de),P4M(0x2df)
+	.long P4M(0x2e0),P4M(0x2e1),P4M(0x2e2),P4M(0x2e3),P4M(0x2e4),P4M(0x2e5),P4M(0x2e6),P4M(0x2e7)
+	.long P4M(0x2e8),P4M(0x2e9),P4M(0x2ea),P4M(0x2eb),P4M(0x2ec),P4M(0x2ed),P4M(0x2ee),P4M(0x2ef)
+	.long P4M(0x2f0),P4M(0x2f1),P4M(0x2f2),P4M(0x2f3),P4M(0x2f4),P4M(0x2f5),P4M(0x2f6),P4M(0x2f7)
+	.long P4M(0x2f8),P4M(0x2f9),P4M(0x2fa),P4M(0x2fb),P4M(0x2fc),P4M(0x2fd),P4M(0x2fe),P4M(0x2ff)
+	.long P4M(0x300),P4M(0x301),P4M(0x302),P4M(0x303),P4M(0x304),P4M(0x305),P4M(0x306),P4M(0x307)
+	.long P4M(0x308),P4M(0x309),P4M(0x30a),P4M(0x30b),P4M(0x30c),P4M(0x30d),P4M(0x30e),P4M(0x30f)
+	.long P4M(0x310),P4M(0x311),P4M(0x312),P4M(0x313),P4M(0x314),P4M(0x315),P4M(0x316),P4M(0x317)
+	.long P4M(0x318),P4M(0x319),P4M(0x31a),P4M(0x31b),P4M(0x31c),P4M(0x31d),P4M(0x31e),P4M(0x31f)
+	.long P4M(0x320),P4M(0x321),P4M(0x322),P4M(0x323),P4M(0x324),P4M(0x325),P4M(0x326),P4M(0x327)
+	.long P4M(0x328),P4M(0x329),P4M(0x32a),P4M(0x32b),P4M(0x32c),P4M(0x32d),P4M(0x32e),P4M(0x32f)
+	.long P4M(0x330),P4M(0x331),P4M(0x332),P4M(0x333),P4M(0x334),P4M(0x335),P4M(0x336),P4M(0x337)
+	.long P4M(0x338),P4M(0x339),P4M(0x33a),P4M(0x33b),P4M(0x33c),P4M(0x33d),P4M(0x33e),P4M(0x33f)
+	.long P4M(0x340),P4M(0x341),P4M(0x342),P4M(0x343),P4M(0x344),P4M(0x345),P4M(0x346),P4M(0x347)
+	.long P4M(0x348),P4M(0x349),P4M(0x34a),P4M(0x34b),P4M(0x34c),P4M(0x34d),P4M(0x34e),P4M(0x34f)
+	.long P4M(0x350),P4M(0x351),P4M(0x352),P4M(0x353),P4M(0x354),P4M(0x355),P4M(0x356),P4M(0x357)
+	.long P4M(0x358),P4M(0x359),P4M(0x35a),P4M(0x35b),P4M(0x35c),P4M(0x35d),P4M(0x35e),P4M(0x35f)
+	.long P4M(0x360),P4M(0x361),P4M(0x362),P4M(0x363),P4M(0x364),P4M(0x365),P4M(0x366),P4M(0x367)
+	.long P4M(0x368),P4M(0x369),P4M(0x36a),P4M(0x36b),P4M(0x36c),P4M(0x36d),P4M(0x36e),P4M(0x36f)
+	.long P4M(0x370),P4M(0x371),P4M(0x372),P4M(0x373),P4M(0x374),P4M(0x375),P4M(0x376),P4M(0x377)
+	.long P4M(0x378),P4M(0x379),P4M(0x37a),P4M(0x37b),P4M(0x37c),P4M(0x37d),P4M(0x37e),P4M(0x37f)
+	.long P4M(0x380),P4M(0x381),P4M(0x382),P4M(0x383),P4M(0x384),P4M(0x385),P4M(0x386),P4M(0x387)
+	.long P4M(0x388),P4M(0x389),P4M(0x38a),P4M(0x38b),P4M(0x38c),P4M(0x38d),P4M(0x38e),P4M(0x38f)
+	.long P4M(0x390),P4M(0x391),P4M(0x392),P4M(0x393),P4M(0x394),P4M(0x395),P4M(0x396),P4M(0x397)
+	.long P4M(0x398),P4M(0x399),P4M(0x39a),P4M(0x39b),P4M(0x39c),P4M(0x39d),P4M(0x39e),P4M(0x39f)
+	.long P4M(0x3a0),P4M(0x3a1),P4M(0x3a2),P4M(0x3a3),P4M(0x3a4),P4M(0x3a5),P4M(0x3a6),P4M(0x3a7)
+	.long P4M(0x3a8),P4M(0x3a9),P4M(0x3aa),P4M(0x3ab),P4M(0x3ac),P4M(0x3ad),P4M(0x3ae),P4M(0x3af)
+	.long P4M(0x3b0),P4M(0x3b1),P4M(0x3b2),P4M(0x3b3),P4M(0x3b4),P4M(0x3b5),P4M(0x3b6),P4M(0x3b7)
+	.long P4M(0x3b8),P4M(0x3b9),P4M(0x3ba),P4M(0x3bb),P4M(0x3bc),P4M(0x3bd),P4M(0x3be),P4M(0x3bf)
+	.long P4M(0x3c0),P4M(0x3c1),P4M(0x3c2),P4M(0x3c3),P4M(0x3c4),P4M(0x3c5),P4M(0x3c6),P4M(0x3c7)
+	.long P4M(0x3c8),P4M(0x3c9),P4M(0x3ca),P4M(0x3cb),P4M(0x3cc),P4M(0x3cd),P4M(0x3ce),P4M(0x3cf)
+	.long P4M(0x3d0),P4M(0x3d1),P4M(0x3d2),P4M(0x3d3),P4M(0x3d4),P4M(0x3d5),P4M(0x3d6),P4M(0x3d7)
+	.long P4M(0x3d8),P4M(0x3d9),P4M(0x3da),P4M(0x3db),P4M(0x3dc),P4M(0x3dd),P4M(0x3de),P4M(0x3df)
+	.long P4M(0x3e0),P4M(0x3e1),P4M(0x3e2),P4M(0x3e3),P4M(0x3e4),P4M(0x3e5),P4M(0x3e6),P4M(0x3e7)
+	.long P4M(0x3e8),P4M(0x3e9),P4M(0x3ea),P4M(0x3eb),P4M(0x3ec),P4M(0x3ed),P4M(0x3ee),P4M(0x3ef)
+	.long P4M(0x3f0),P4M(0x3f1),P4M(0x3f2),P4M(0x3f3),P4M(0x3f4),P4M(0x3f5),P4M(0x3f6),P4M(0x3f7)
+	.long P4M(0x3f8),P4M(0x3f9),P4M(0x3fa),P4M(0x3fb),P4M(0x3fc),P4M(0x3fd),P4M(0x3fe),P4M(0x3ff)
+
+#if 0 // someday
+#if CONFIG_ARCH_X86_64
+/* 64 bit GDT ... */
+gdt64:
+	.quad	$0x0000000000000000		/* NULL descriptor */
+	.quad	$0x0020980000000000		/* CS */
+
+gdt64p:
+	.word	15 // 2*8-1
+	.quad	$gdt64
+.align 4096
+
+pml2:	.quad P2M(0x000),P2M(0x001),P2M(0x002),P2M(0x003),P2M(0x004),P2M(0x005),P2M(0x006),P2M(0x007)
+	.quad P2M(0x008),P2M(0x009),P2M(0x00a),P2M(0x00b),P2M(0x00c),P2M(0x00d),P2M(0x00e),P2M(0x00f)
+	.quad P2M(0x010),P2M(0x011),P2M(0x012),P2M(0x013),P2M(0x014),P2M(0x015),P2M(0x016),P2M(0x017)
+	.quad P2M(0x018),P2M(0x019),P2M(0x01a),P2M(0x01b),P2M(0x01c),P2M(0x01d),P2M(0x01e),P2M(0x01f)
+	.quad P2M(0x020),P2M(0x021),P2M(0x022),P2M(0x023),P2M(0x024),P2M(0x025),P2M(0x026),P2M(0x027)
+	.quad P2M(0x028),P2M(0x029),P2M(0x02a),P2M(0x02b),P2M(0x02c),P2M(0x02d),P2M(0x02e),P2M(0x02f)
+	.quad P2M(0x030),P2M(0x031),P2M(0x032),P2M(0x033),P2M(0x034),P2M(0x035),P2M(0x036),P2M(0x037)
+	.quad P2M(0x038),P2M(0x039),P2M(0x03a),P2M(0x03b),P2M(0x03c),P2M(0x03d),P2M(0x03e),P2M(0x03f)
+	.quad P2M(0x040),P2M(0x041),P2M(0x042),P2M(0x043),P2M(0x044),P2M(0x045),P2M(0x046),P2M(0x047)
+	.quad P2M(0x048),P2M(0x049),P2M(0x04a),P2M(0x04b),P2M(0x04c),P2M(0x04d),P2M(0x04e),P2M(0x04f)
+	.quad P2M(0x050),P2M(0x051),P2M(0x052),P2M(0x053),P2M(0x054),P2M(0x055),P2M(0x056),P2M(0x057)
+	.quad P2M(0x058),P2M(0x059),P2M(0x05a),P2M(0x05b),P2M(0x05c),P2M(0x05d),P2M(0x05e),P2M(0x05f)
+	.quad P2M(0x060),P2M(0x061),P2M(0x062),P2M(0x063),P2M(0x064),P2M(0x065),P2M(0x066),P2M(0x067)
+	.quad P2M(0x068),P2M(0x069),P2M(0x06a),P2M(0x06b),P2M(0x06c),P2M(0x06d),P2M(0x06e),P2M(0x06f)
+	.quad P2M(0x070),P2M(0x071),P2M(0x072),P2M(0x073),P2M(0x074),P2M(0x075),P2M(0x076),P2M(0x077)
+	.quad P2M(0x078),P2M(0x079),P2M(0x07a),P2M(0x07b),P2M(0x07c),P2M(0x07d),P2M(0x07e),P2M(0x07f)
+	.quad P2M(0x080),P2M(0x081),P2M(0x082),P2M(0x083),P2M(0x084),P2M(0x085),P2M(0x086),P2M(0x087)
+	.quad P2M(0x088),P2M(0x089),P2M(0x08a),P2M(0x08b),P2M(0x08c),P2M(0x08d),P2M(0x08e),P2M(0x08f)
+	.quad P2M(0x090),P2M(0x091),P2M(0x092),P2M(0x093),P2M(0x094),P2M(0x095),P2M(0x096),P2M(0x097)
+	.quad P2M(0x098),P2M(0x099),P2M(0x09a),P2M(0x09b),P2M(0x09c),P2M(0x09d),P2M(0x09e),P2M(0x09f)
+	.quad P2M(0x0a0),P2M(0x0a1),P2M(0x0a2),P2M(0x0a3),P2M(0x0a4),P2M(0x0a5),P2M(0x0a6),P2M(0x0a7)
+	.quad P2M(0x0a8),P2M(0x0a9),P2M(0x0aa),P2M(0x0ab),P2M(0x0ac),P2M(0x0ad),P2M(0x0ae),P2M(0x0af)
+	.quad P2M(0x0b0),P2M(0x0b1),P2M(0x0b2),P2M(0x0b3),P2M(0x0b4),P2M(0x0b5),P2M(0x0b6),P2M(0x0b7)
+	.quad P2M(0x0b8),P2M(0x0b9),P2M(0x0ba),P2M(0x0bb),P2M(0x0bc),P2M(0x0bd),P2M(0x0be),P2M(0x0bf)
+	.quad P2M(0x0c0),P2M(0x0c1),P2M(0x0c2),P2M(0x0c3),P2M(0x0c4),P2M(0x0c5),P2M(0x0c6),P2M(0x0c7)
+	.quad P2M(0x0c8),P2M(0x0c9),P2M(0x0ca),P2M(0x0cb),P2M(0x0cc),P2M(0x0cd),P2M(0x0ce),P2M(0x0cf)
+	.quad P2M(0x0d0),P2M(0x0d1),P2M(0x0d2),P2M(0x0d3),P2M(0x0d4),P2M(0x0d5),P2M(0x0d6),P2M(0x0d7)
+	.quad P2M(0x0d8),P2M(0x0d9),P2M(0x0da),P2M(0x0db),P2M(0x0dc),P2M(0x0dd),P2M(0x0de),P2M(0x0df)
+	.quad P2M(0x0e0),P2M(0x0e1),P2M(0x0e2),P2M(0x0e3),P2M(0x0e4),P2M(0x0e5),P2M(0x0e6),P2M(0x0e7)
+	.quad P2M(0x0e8),P2M(0x0e9),P2M(0x0ea),P2M(0x0eb),P2M(0x0ec),P2M(0x0ed),P2M(0x0ee),P2M(0x0ef)
+	.quad P2M(0x0f0),P2M(0x0f1),P2M(0x0f2),P2M(0x0f3),P2M(0x0f4),P2M(0x0f5),P2M(0x0f6),P2M(0x0f7)
+	.quad P2M(0x0f8),P2M(0x0f9),P2M(0x0fa),P2M(0x0fb),P2M(0x0fc),P2M(0x0fd),P2M(0x0fe),P2M(0x0ff)
+	.quad P2M(0x100),P2M(0x101),P2M(0x102),P2M(0x103),P2M(0x104),P2M(0x105),P2M(0x106),P2M(0x107)
+	.quad P2M(0x108),P2M(0x109),P2M(0x10a),P2M(0x10b),P2M(0x10c),P2M(0x10d),P2M(0x10e),P2M(0x10f)
+	.quad P2M(0x110),P2M(0x111),P2M(0x112),P2M(0x113),P2M(0x114),P2M(0x115),P2M(0x116),P2M(0x117)
+	.quad P2M(0x118),P2M(0x119),P2M(0x11a),P2M(0x11b),P2M(0x11c),P2M(0x11d),P2M(0x11e),P2M(0x11f)
+	.quad P2M(0x120),P2M(0x121),P2M(0x122),P2M(0x123),P2M(0x124),P2M(0x125),P2M(0x126),P2M(0x127)
+	.quad P2M(0x128),P2M(0x129),P2M(0x12a),P2M(0x12b),P2M(0x12c),P2M(0x12d),P2M(0x12e),P2M(0x12f)
+	.quad P2M(0x130),P2M(0x131),P2M(0x132),P2M(0x133),P2M(0x134),P2M(0x135),P2M(0x136),P2M(0x137)
+	.quad P2M(0x138),P2M(0x139),P2M(0x13a),P2M(0x13b),P2M(0x13c),P2M(0x13d),P2M(0x13e),P2M(0x13f)
+	.quad P2M(0x140),P2M(0x141),P2M(0x142),P2M(0x143),P2M(0x144),P2M(0x145),P2M(0x146),P2M(0x147)
+	.quad P2M(0x148),P2M(0x149),P2M(0x14a),P2M(0x14b),P2M(0x14c),P2M(0x14d),P2M(0x14e),P2M(0x14f)
+	.quad P2M(0x150),P2M(0x151),P2M(0x152),P2M(0x153),P2M(0x154),P2M(0x155),P2M(0x156),P2M(0x157)
+	.quad P2M(0x158),P2M(0x159),P2M(0x15a),P2M(0x15b),P2M(0x15c),P2M(0x15d),P2M(0x15e),P2M(0x15f)
+	.quad P2M(0x160),P2M(0x161),P2M(0x162),P2M(0x163),P2M(0x164),P2M(0x165),P2M(0x166),P2M(0x167)
+	.quad P2M(0x168),P2M(0x169),P2M(0x16a),P2M(0x16b),P2M(0x16c),P2M(0x16d),P2M(0x16e),P2M(0x16f)
+	.quad P2M(0x170),P2M(0x171),P2M(0x172),P2M(0x173),P2M(0x174),P2M(0x175),P2M(0x176),P2M(0x177)
+	.quad P2M(0x178),P2M(0x179),P2M(0x17a),P2M(0x17b),P2M(0x17c),P2M(0x17d),P2M(0x17e),P2M(0x17f)
+	.quad P2M(0x180),P2M(0x181),P2M(0x182),P2M(0x183),P2M(0x184),P2M(0x185),P2M(0x186),P2M(0x187)
+	.quad P2M(0x188),P2M(0x189),P2M(0x18a),P2M(0x18b),P2M(0x18c),P2M(0x18d),P2M(0x18e),P2M(0x18f)
+	.quad P2M(0x190),P2M(0x191),P2M(0x192),P2M(0x193),P2M(0x194),P2M(0x195),P2M(0x196),P2M(0x197)
+	.quad P2M(0x198),P2M(0x199),P2M(0x19a),P2M(0x19b),P2M(0x19c),P2M(0x19d),P2M(0x19e),P2M(0x19f)
+	.quad P2M(0x1a0),P2M(0x1a1),P2M(0x1a2),P2M(0x1a3),P2M(0x1a4),P2M(0x1a5),P2M(0x1a6),P2M(0x1a7)
+	.quad P2M(0x1a8),P2M(0x1a9),P2M(0x1aa),P2M(0x1ab),P2M(0x1ac),P2M(0x1ad),P2M(0x1ae),P2M(0x1af)
+	.quad P2M(0x1b0),P2M(0x1b1),P2M(0x1b2),P2M(0x1b3),P2M(0x1b4),P2M(0x1b5),P2M(0x1b6),P2M(0x1b7)
+	.quad P2M(0x1b8),P2M(0x1b9),P2M(0x1ba),P2M(0x1bb),P2M(0x1bc),P2M(0x1bd),P2M(0x1be),P2M(0x1bf)
+	.quad P2M(0x1c0),P2M(0x1c1),P2M(0x1c2),P2M(0x1c3),P2M(0x1c4),P2M(0x1c5),P2M(0x1c6),P2M(0x1c7)
+	.quad P2M(0x1c8),P2M(0x1c9),P2M(0x1ca),P2M(0x1cb),P2M(0x1cc),P2M(0x1cd),P2M(0x1ce),P2M(0x1cf)
+	.quad P2M(0x1d0),P2M(0x1d1),P2M(0x1d2),P2M(0x1d3),P2M(0x1d4),P2M(0x1d5),P2M(0x1d6),P2M(0x1d7)
+	.quad P2M(0x1d8),P2M(0x1d9),P2M(0x1da),P2M(0x1db),P2M(0x1dc),P2M(0x1dd),P2M(0x1de),P2M(0x1df)
+	.quad P2M(0x1e0),P2M(0x1e1),P2M(0x1e2),P2M(0x1e3),P2M(0x1e4),P2M(0x1e5),P2M(0x1e6),P2M(0x1e7)
+	.quad P2M(0x1e8),P2M(0x1e9),P2M(0x1ea),P2M(0x1eb),P2M(0x1ec),P2M(0x1ed),P2M(0x1ee),P2M(0x1ef)
+	.quad P2M(0x1f0),P2M(0x1f1),P2M(0x1f2),P2M(0x1f3),P2M(0x1f4),P2M(0x1f5),P2M(0x1f6),P2M(0x1f7)
+	.quad P2M(0x1f8),P2M(0x1f9),P2M(0x1fa),P2M(0x1fb),P2M(0x1fc),P2M(0x1fd),P2M(0x1fe),P2M(0x1ff)
+
+pml3:
+	.quad pml2 + 5 // PTE(pml2)
+.align 4096
+pml4:
+	.quad pml3 + 5 // PTE(pml3)
+#endif
+#endif // someday
diff --git a/src/arch/x86/lib/paging.S b/src/arch/x86/lib/paging.S
new file mode 100644
index 0000000..71d3b36
--- /dev/null
+++ b/src/arch/x86/lib/paging.S
@@ -0,0 +1,58 @@
+#include <cpu/x86/cr.h>
+
+	jmp code
+
+#include "pagetables.S"
+
+code:
+	movl	$PageMapLevel2, %ecx		/* load address of page directory */
+	movl	%ecx, %cr3
+	jmp	1f
+1:
+	movl	%cr4, %edx
+	orl	$CR4_PSE, %edx			/* 4m pages */
+	movl	%edx, %cr4
+
+	movl	%cr0, %edx
+	orl	$CR0_PG, %edx
+
+	movl	$paging32, %ecx
+	movl	%edx, %cr0
+	jmp	*%ecx
+
+/* if we get here, we're in paged 32-bit mode */
+paging32:
+#if 0 // someday
+#if CONFIG_ARCH_X86_64
+	movl	%cr4, %eax
+	andl	$~Pse, %eax			/* Page Size */
+	orl	$(Pge|Pae), %eax		/* Page Global, Phys. Address */
+	movl	%eax, %cr4
+
+	movl	$Efer, %ecx			/* Extended Feature Enable */
+	rdmsr
+	orl	$Lme, %eax			/* Long Mode Enable */
+	wrmsr
+
+	movl	%cr0, %dx
+	andl	$~(Cd|Nw|Ts|Mp), %edx
+	orl	$(Pg|Wp), %edx			/* Enable Paging */
+	movl	%edx, %cr0
+
+	jmp paging64
+
+.code64
+paging64:
+
+	movq	gdt64, %RX
+	movl	(%RX), %gdtr
+
+	XORQ	%edx, %edx
+	movw	%edx, %ds				/* not used in long mode */
+	movw	%edx, %es				/* not used in long mode */
+	movw	%edx, %fs
+	movw	%edx, %gs
+	movw	%edx, %ss				/* not used in long mode */
+
+#endif
+#endif //someday