[PATCH 4/4] UML - Eliminate use of libc PAGE_SIZE

From: Jeff Dike
Date: Thu Nov 17 2005 - 15:18:01 EST


On some systems, libc PAGE_SIZE calls getpagesize, which can't
happen from a stub. So, I use UM_KERN_PAGE_SIZE, which is less
variable in its definition, instead.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: linux-2.6.15/arch/um/kernel/skas/clone.c
===================================================================
--- linux-2.6.15.orig/arch/um/kernel/skas/clone.c 2005-11-17 14:58:54.000000000 -0500
+++ linux-2.6.15/arch/um/kernel/skas/clone.c 2005-11-17 14:59:40.000000000 -0500
@@ -9,9 +9,13 @@
#include "stub-data.h"
#include "uml-config.h"
#include "sysdep/stub.h"
+#include "kern_constants.h"

/* This is in a separate file because it needs to be compiled with any
* extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
+ *
+ * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
+ * on some systems.
*/

#define STUB_DATA(field) (((struct stub_data *) UML_CONFIG_STUB_DATA)->field)
@@ -22,7 +26,7 @@ stub_clone_handler(void)
long err;

err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
- UML_CONFIG_STUB_DATA + PAGE_SIZE / 2 -
+ UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE / 2 -
sizeof(void *));
if(err != 0)
goto out;
@@ -36,9 +40,10 @@ stub_clone_handler(void)
if(err)
goto out;

- err = stub_syscall6(STUB_MMAP_NR, UML_CONFIG_STUB_DATA, PAGE_SIZE,
- PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED,
- STUB_DATA(fd), STUB_DATA(offset));
+ err = stub_syscall6(STUB_MMAP_NR, UML_CONFIG_STUB_DATA,
+ UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_FIXED | MAP_SHARED, STUB_DATA(fd),
+ STUB_DATA(offset));
out:
/* save current result. Parent: pid; child: retcode of mmap */
STUB_DATA(err) = err;

-
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