Bring PAE code back to life, in a different form. This diff (via bluhm then

to deraadt, then myself) brings the PAE pmap on i386 (not touched in any
significant way for years) closer to the current non-PAE pmap and allows
us to take a big next step toward better i386 W^X in the kernel (similar to
what we did a few months ago on amd64). Unlike the original PAE pmap, this
diff will not be supporting > 4GB physical memory on i386 - this effort is
specifically geared toward providing W^X (via NX) only.

There still seems to be a bug removing certain pmap entries when PAE is
enabled, so I'm leaving PAE mode disabled for the moment until we can
figure out what is going on, but with this diff in the tree hopefully
others can help.

The pmap functions now operate through function pointers, due to the need
to support both non-PAE and PAE forms. My unscientific testing showed
less than 0.3% (a third of a percent) slowdown with this approach during
a base build.

Discussed for months with guenther, kettenis, and deraadt.

ok kettenis@, deraadt@

1 files changed, 1 insertions, 24 deletions

diff --git a/sys/arch/i386/include/pte.h b/sys/arch/i386/include/pte.h
index efaa89caaec..c0e1ccfb83d 100644
--- a/sys/arch/i386/include/pte.h
+++ b/sys/arch/i386/include/pte.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pte.h,v 1.20 2015/03/13 23:23:13 mlarkin Exp $	*/
+/*	$OpenBSD: pte.h,v 1.21 2015/04/12 18:37:54 mlarkin Exp $	*/
 /*	$NetBSD: pte.h,v 1.11 1998/02/06 21:58:05 thorpej Exp $	*/
 
 /*
@@ -37,33 +37,12 @@
 #ifndef _MACHINE_PTE_H_
 #define _MACHINE_PTE_H_
 
-#if !defined(_LOCORE)
-
-/*
- * here we define the data types for PDEs and PTEs
- */
-
-typedef u_int32_t pd_entry_t;		/* PDE */
-typedef u_int32_t pt_entry_t;		/* PTE */
-
-#endif
-
 /*
  * now we define various for playing with virtual addresses
  */
 
 #define	PDSHIFT		22		/* offset of PD index in VA */
 #define	NBPD		(1 << PDSHIFT)	/* # bytes mapped by PD (4MB) */
-#define	PDOFSET		(NBPD-1)	/* mask for non-PD part of VA */
-#if 0 /* not used? */
-#define	NPTEPD		(NBPD / PAGE_SIZE)	/* # of PTEs in a PD */
-#else
-#define	PTES_PER_PTP	(NBPD / PAGE_SIZE)	/* # of PTEs in a PTP */
-#endif
-
-#define PAGE_MASK_L2	(NBPD - 1)
-
-#define	i386_round_pdr(x)	((((unsigned)(x)) + PDOFSET) & ~PDOFSET)
 
 /*
  * here we define the bits of the PDE/PTE, as described above:
@@ -87,8 +66,6 @@ typedef u_int32_t pt_entry_t;		/* PTE */
 #define PG_AVAIL2	0x00000400	/* ignored by hardware */
 #define PG_AVAIL3	0x00000800	/* ignored by hardware */
 #define	PG_PATLG	0x00001000	/* PAT on large pages */
-#define PG_FRAME	0xfffff000	/* page frame mask */
-#define PG_LGFRAME	0xffc00000	/* large (4M) page frame mask */
 
 /* Cacheability bits when we are using PAT */
 #define	PG_WB		(0)		/* The default */