[PATCH] x86_64: Add boot option to disable randomized mappings and cleanup

AMD SimNow!'s JIT doesn't like them at all in the guest. For distribution
installation it's easiest if it's a boot time option.

Also I moved the variable to a more appropiate place and make
it independent from sysctl

And marked __read_mostly which it is.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/kernel-parameters.txt

@@ -1638,6 +1638,9 @@ running once the system is up.
 			Format:
 			<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
 
+	norandmaps	Don't use address space randomization
+			Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
+
 
 ______________________________________________________________________
 Changelog:

arch/i386/kernel/cpu/transmeta.c

@@ -1,4 +1,5 @@
 #include <linux/kernel.h>
+#include <linux/mm.h>
 #include <linux/init.h>
 #include <asm/processor.h>
 #include <asm/msr.h>

include/linux/kernel.h

@@ -326,12 +326,6 @@ struct sysinfo {
 /* Force a compilation error if condition is true */
 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 
-#ifdef CONFIG_SYSCTL
-extern int randomize_va_space;
-#else
-#define randomize_va_space 1
-#endif
-
 /* Trap pasters of __FUNCTION__ at compile-time */
 #define __FUNCTION__ (__func__)
 

include/linux/mm.h

@@ -1051,5 +1051,7 @@ int shrink_slab(unsigned long scanned, gfp_t gfp_mask,
 void drop_pagecache(void);
 void drop_slab(void);
 
+extern int randomize_va_space;
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */

kernel/sysctl.c

@@ -126,8 +126,6 @@ extern int sysctl_hz_timer;
 extern int acct_parm[];
 #endif
 
-int randomize_va_space = 1;
-
 static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
 		       ctl_table *, void **);
 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,

mm/memory.c

@@ -82,6 +82,16 @@ EXPORT_SYMBOL(num_physpages);
 EXPORT_SYMBOL(high_memory);
 EXPORT_SYMBOL(vmalloc_earlyreserve);
 
+int randomize_va_space __read_mostly = 1;
+
+static int __init disable_randmaps(char *s)
+{
+	randomize_va_space = 0;
+	return 0;
+}
+__setup("norandmaps", disable_randmaps);
+
+
 /*
  * If a p?d_bad entry is found while walking page tables, report
  * the error, before resetting entry to p?d_none.  Usually (but