allocate uareas contiguously and access them via the direct map.

sys/arch/amd64/include/cpu.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: cpu.h,v 1.59 2008/12/30 12:35:23 pooka Exp $	*/
+/*	$NetBSD: cpu.h,v 1.60 2012/01/21 16:48:56 chs Exp $	*/
 
 /*-
  * Copyright (c) 1990 The Regents of the University of California.
@@ -89,6 +89,9 @@ cpu_set_curpri(int pri)
 #define CLKF_INTR(frame)	(curcpu()->ci_idepth > 0)
 #define LWP_PC(l)		((l)->l_md.md_regs->tf_rip)
 
+void	*cpu_uarea_alloc(bool);
+bool	cpu_uarea_free(void *);
+
 #endif	/* _KERNEL */
 
 #else	/*	__x86_64__	*/

sys/arch/amd64/include/types.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: types.h,v 1.40 2011/12/04 16:24:13 chs Exp $	*/
+/*	$NetBSD: types.h,v 1.41 2012/01/21 16:48:56 chs Exp $	*/
 
 /*-
  * Copyright (c) 1990 The Regents of the University of California.
@@ -99,6 +99,7 @@ typedef	volatile unsigned char		__cpu_simple_lock_t;
 #define	__HAVE_DIRECT_MAP 1
 #define	__HAVE_MM_MD_DIRECT_MAPPED_IO
 #define	__HAVE_MM_MD_DIRECT_MAPPED_PHYS
+#define	__HAVE_CPU_UAREA_ROUTINES
 #endif
 #endif
 

sys/arch/x86/x86/vm_machdep.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: vm_machdep.c,v 1.13 2011/02/10 14:46:48 pooka Exp $	*/
+/*	$NetBSD: vm_machdep.c,v 1.14 2012/01/21 16:48:57 chs Exp $	*/
 
 /*-
  * Copyright (c) 1982, 1986 The Regents of the University of California.
@@ -80,7 +80,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.13 2011/02/10 14:46:48 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.14 2012/01/21 16:48:57 chs Exp $");
 
 #include "opt_mtrr.h"
 
@@ -93,7 +93,7 @@ __KERNEL_RCSID(0, "$NetBSD: vm_machdep.c,v 1.13 2011/02/10 14:46:48 pooka Exp $"
 #include <sys/exec.h>
 #include <sys/ptrace.h>
 
-#include <uvm/uvm_extern.h>
+#include <uvm/uvm.h>
 
 #include <machine/cpu.h>
 #include <machine/gdt.h>
@@ -356,3 +356,58 @@ vunmapbuf(struct buf *bp, vsize_t len)
 	bp->b_data = bp->b_saveaddr;
 	bp->b_saveaddr = 0;
 }
+
+#ifdef __HAVE_CPU_UAREA_ROUTINES
+void *
+cpu_uarea_alloc(bool system)
+{
+	struct pglist pglist;
+	int error;
+
+	/*
+	 * Allocate a new physically contiguous uarea which can be
+	 * direct-mapped.
+	 */
+	error = uvm_pglistalloc(USPACE, 0, ptoa(physmem), 0, 0, &pglist, 1, 1);
+	if (error) {
+		return NULL;
+	}
+
+	/*
+	 * Get the physical address from the first page.
+	 */
+	const struct vm_page * const pg = TAILQ_FIRST(&pglist);
+	KASSERT(pg != NULL);
+	const paddr_t pa = VM_PAGE_TO_PHYS(pg);
+
+	/*
+	 * We need to return a direct-mapped VA for the pa.
+	 */
+
+	return (void *)PMAP_MAP_POOLPAGE(pa);
+}
+
+/*
+ * Return true if we freed it, false if we didn't.
+ */
+bool
+cpu_uarea_free(void *vva)
+{
+	vaddr_t va = (vaddr_t) vva;
+
+	if (va >= VM_MIN_KERNEL_ADDRESS && va < VM_MAX_KERNEL_ADDRESS) {
+		return false;
+	}
+
+	/*
+	 * Since the pages are physically contiguous, the vm_page structures
+	 * will be as well.
+	 */
+	struct vm_page *pg = PHYS_TO_VM_PAGE(PMAP_UNMAP_POOLPAGE(va));
+	KASSERT(pg != NULL);
+	for (size_t i = 0; i < UPAGES; i++, pg++) {
+		uvm_pagefree(pg);
+	}
+	return true;
+}
+#endif /* __HAVE_CPU_UAREA_ROUTINES */