From: Dmitry V. Levin <ldv@altlinux.org>
Date: Tue, 5 Mar 2013 14:58:24 +0000 (+0000)
Subject: Use sysconf(_SC_PAGESIZE) instead of hardcoded PAGE_SHIFT
X-Git-Tag: v4.8~102
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c76a363af8bfc7b83558253fae38ae3d255e0aa9;p=strace

Use sysconf(_SC_PAGESIZE) instead of hardcoded PAGE_SHIFT

PAGE_SHIFT couldn't be reliably obtained at compile time,
thanks to Chris Metcalf for the hint.

* mem.c: Do not include <sys/user.h>.
[SH64] Do not include <asm/page.h>.
(get_pagesize): New function.
(sys_mmap_pgoff, sys_old_mmap_pgoff): Use it.
---

diff --git a/mem.c b/mem.c
index 6f22922d..3bd41b46 100644
--- a/mem.c
+++ b/mem.c
@@ -40,14 +40,15 @@
 # endif
 #endif
 
-#include <sys/user.h>	/* for PAGE_SHIFT */
-#if defined(SH64)
-# include <asm/page.h>	/* for PAGE_SHIFT */
-#endif
-#if !defined(PAGE_SHIFT)
-# warning Failed to get PAGE_SHIFT, assuming 12
-# define PAGE_SHIFT 12
-#endif
+static unsigned long
+get_pagesize()
+{
+	static unsigned long pagesize;
+
+	if (!pagesize)
+		pagesize = sysconf(_SC_PAGESIZE);
+	return pagesize;
+}
 
 int
 sys_brk(struct tcb *tcp)
@@ -295,7 +296,7 @@ sys_old_mmap_pgoff(struct tcb *tcp)
 	for (i = 0; i < 5; i++)
 		u_arg[i] = (unsigned long) narrow_arg[i];
 	offset = narrow_arg[5];
-	offset <<= PAGE_SHIFT;
+	offset *= get_pagesize();
 	return print_mmap(tcp, u_arg, offset);
 }
 #endif
@@ -324,7 +325,7 @@ sys_mmap_pgoff(struct tcb *tcp)
 	/* Try test/mmap_offset_decode.c */
 	unsigned long long offset;
 	offset = (unsigned long) tcp->u_arg[5];
-	offset <<= PAGE_SHIFT;
+	offset *= get_pagesize();
 	return print_mmap(tcp, tcp->u_arg, offset);
 }