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Date:      Thu, 21 Jan 2016 18:17:19 +0000 (UTC)
From:      Brooks Davis <brooks@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r294523 - head/lib/libc/gmon
Message-ID:  <201601211817.u0LIHJ7a029843@repo.freebsd.org>
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Author: brooks
Date: Thu Jan 21 18:17:19 2016
New Revision: 294523
URL: https://svnweb.freebsd.org/changeset/base/294523

Log:
  Replace the last non-optional use of sbrk() in the tree with mmap().
  
  All gmon want's is a region of memory without the overhead of malloc().
  Just mapping some pages with mmap is an easy way to accomplish this.
  
  Approved by:	jhb, cem, emaste
  Obtained from:	CheriBSD (bf33e1e70b368ababde74aa3ac70d108c8a52c69)
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D5005

Modified:
  head/lib/libc/gmon/gmon.c

Modified: head/lib/libc/gmon/gmon.c
==============================================================================
--- head/lib/libc/gmon/gmon.c	Thu Jan 21 18:02:31 2016	(r294522)
+++ head/lib/libc/gmon/gmon.c	Thu Jan 21 18:17:19 2016	(r294523)
@@ -37,6 +37,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/time.h>
 #include <sys/gmon.h>
+#include <sys/mman.h>
 #include <sys/sysctl.h>
 
 #include <err.h>
@@ -50,14 +51,6 @@ __FBSDID("$FreeBSD$");
 
 #include "libc_private.h"
 
-#if defined(__i386__) || defined(__sparc64__) || defined(__amd64__) || (defined(__powerpc__) && !defined(__powerpc64__))
-extern char *minbrk __asm (".minbrk");
-#elif defined(__powerpc64__)
-extern char *minbrk __asm ("_minbrk");
-#else
-extern char *minbrk __asm ("minbrk");
-#endif
-
 struct gmonparam _gmonparam = { GMON_PROF_OFF };
 
 static int	s_scale;
@@ -94,8 +87,9 @@ monstartup(u_long lowpc, u_long highpc)
 		p->tolimit = MAXARCS;
 	p->tossize = p->tolimit * sizeof(struct tostruct);
 
-	cp = sbrk(p->kcountsize + p->fromssize + p->tossize);
-	if (cp == (char *)-1) {
+	cp = mmap(NULL, p->kcountsize + p->fromssize + p->tossize,
+	    PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
+	if (cp == MAP_FAILED) {
 		ERR("monstartup: out of memory\n");
 		return;
 	}
@@ -108,7 +102,6 @@ monstartup(u_long lowpc, u_long highpc)
 	cp += p->kcountsize;
 	p->froms = (u_short *)cp;
 
-	minbrk = sbrk(0);
 	p->tos[0].link = 0;
 
 	o = p->highpc - p->lowpc;

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