svn commit: r207131 - in head/sys/mips: conf sibyte

[Juli Mallett]

Author: jmallett
Date: Fri Apr 23 19:20:56 2010
New Revision: 207131
URL: http://svn.freebsd.org/changeset/base/207131

Log:
  o) Remove default MAXMEM on SWARM; pmap can readily use lmem for >512M
     physical addresses.
  o) Set a local maxmem in sb_machdep.c to avoid trying to use pages over 2^64
     under 32-bit ABIs.  Our pmap needs corrected to use vm_paddr_t consistently,
     then we can make vm_paddr_t 64-bit under 32-bit ABIs and add code in pmap
     to limit phys_avail by the maximum PFN that a 32-bit PTE can hold.

Modified:
  head/sys/mips/conf/SWARM
  head/sys/mips/sibyte/sb_machdep.c

Modified: head/sys/mips/conf/SWARM
==============================================================================
--- head/sys/mips/conf/SWARM	Fri Apr 23 18:53:17 2010	(r207130)
+++ head/sys/mips/conf/SWARM	Fri Apr 23 19:20:56 2010	(r207131)
@@ -8,12 +8,6 @@ options		CPU_SB1
 files		"../sibyte/files.sibyte"
 hints		"SWARM.hints"
 
-#
-# 32-bit kernel cannot deal with physical memory beyond 4GB
-# XXX pmap assumes that all the memory can be mapped using KSEG0
-#
-options		MAXMEM=512*1024
-
 options		CFE
 options		CFE_CONSOLE
 options		CFE_ENV

Modified: head/sys/mips/sibyte/sb_machdep.c
==============================================================================
--- head/sys/mips/sibyte/sb_machdep.c	Fri Apr 23 18:53:17 2010	(r207130)
+++ head/sys/mips/sibyte/sb_machdep.c	Fri Apr 23 19:20:56 2010	(r207131)
@@ -158,6 +158,17 @@ mips_init(void)
 	TUNABLE_INT_FETCH("hw.physmem", &tmp);
 	maxmem = (uint64_t)tmp * 1024;
 
+	/*
+	 * XXX
+	 * If we used vm_paddr_t consistently in pmap, etc., we could
+	 * use 64-bit page numbers on !n64 systems, too, like i386
+	 * does with PAE.
+	 */
+#if !defined(__mips_n64)
+	if (maxmem == 0 || maxmem > 0xffffffff)
+		maxmem = 0xffffffff;
+#endif
+
 #ifdef CFE
 	/*
 	 * Query DRAM memory map from CFE.