[patch] new patch number 4

alpha-sysctl-uac-updated.patch (text/plain), 4.61 KB, created by Mike Pagano on 2008-04-13 21:26:50 UTC

--- src/arch/alpha/Kconfig.orig	2008-04-11 19:24:19.000000000 -0400
+++ src/arch/alpha/Kconfig	2008-04-11 19:28:07.000000000 -0400
@@ -616,6 +616,32 @@ config VERBOSE_MCHECK_ON
 
 	  Take the default (1) unless you want more control or more info.
 
+config ALPHA_UAC_SYSCTL
+	bool "Configure UAC policy via sysctl"
+	depends on SYSCTL
+	default y
+	---help---
+	  Configuring the UAC (unaligned access control) policy on a Linux
+	  system usually involves setting a compile time define. If you say
+	  Y here, you will be able to modify the UAC policy at runtime using
+	  the /proc interface.
+
+	  The UAC policy defines the action Linux should take when an
+	  unaligned memory access occurs. The action can include printing a
+	  warning message (NOPRINT), sending a signal to the offending
+	  program to help developers debug their applications (SIGBUS), or
+	  disabling the transparent fixing (NOFIX).
+
+	  The sysctls will be initialized to the compile-time defined UAC
+	  policy. You can change these manually, or with the sysctl(8)
+	  userspace utility.
+
+	  To disable the warning messages at runtime, you would use
+
+	    echo 1 > /proc/sys/kernel/uac/noprint
+
+	  This is pretty harmless. Say Y if you're not sure.
+
 source "drivers/pci/Kconfig"
 source "drivers/eisa/Kconfig"
 
--- src/arch/alpha/kernel/traps.c.orig	2008-04-11 19:24:50.000000000 -0400
+++ src/arch/alpha/kernel/traps.c	2008-04-13 17:07:10.000000000 -0400
@@ -102,6 +102,52 @@ static char * ireg_name[] = {"v0", "t0",
 			   "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"};
 #endif
 
+#ifdef CONFIG_ALPHA_UAC_SYSCTL
+
+#include <linux/sysctl.h>
+
+static int enabled_noprint = 0;
+static int enabled_sigbus = 0;
+static int enabled_nofix = 0;
+
+ctl_table uac_table[] = {
+   	{
+		.ctl_name 	= CTL_UNNUMBERED,
+		.procname 	= "noprint", 
+		.data 		= &enabled_noprint, 
+		.maxlen 	= sizeof (int), 
+		.mode 		= 0644, 
+		.proc_handler = &proc_dointvec,
+	},
+   	{
+		.ctl_name 	= CTL_UNNUMBERED,
+		.procname 	= "sigbus", 
+		.data 		= &enabled_sigbus, 
+		.maxlen 	= sizeof (int), 
+		.mode 		= 0644, 
+		.proc_handler = &proc_dointvec,
+	},
+   	{
+		.ctl_name 	= CTL_UNNUMBERED,
+		.procname 	= "nofix", 
+		.data 		= &enabled_nofix, 
+		.maxlen 	= sizeof (int), 
+		.mode 		= 0644, 
+		.proc_handler = &proc_dointvec,
+	},
+	{ .ctl_name = 0 }
+};
+
+static int __init init_uac_sysctl(void)
+{
+   /* Initialize sysctls with the #defined UAC policy */
+   enabled_noprint = (test_thread_flag (TIF_UAC_NOPRINT)) ? 1 : 0;
+   enabled_sigbus = (test_thread_flag (TIF_UAC_SIGBUS)) ? 1 : 0;
+   enabled_nofix = (test_thread_flag (TIF_UAC_NOFIX)) ? 1 : 0;
+   return 0;
+}
+#endif
+
 static void
 dik_show_code(unsigned int *pc)
 {
@@ -780,7 +826,11 @@ do_entUnaUser(void __user * va, unsigned
 	/* Check the UAC bits to decide what the user wants us to do
 	   with the unaliged access.  */
 
+#ifndef CONFIG_ALPHA_UAC_SYSCTL
 	if (!test_thread_flag (TIF_UAC_NOPRINT)) {
+#else  /* CONFIG_ALPHA_UAC_SYSCTL */
+   if (!(enabled_noprint)) {
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */
 		if (cnt >= 5 && jiffies - last_time > 5*HZ) {
 			cnt = 0;
 		}
@@ -791,10 +841,18 @@ do_entUnaUser(void __user * va, unsigned
 		}
 		last_time = jiffies;
 	}
+#ifndef CONFIG_ALPHA_UAC_SYSCTL
 	if (test_thread_flag (TIF_UAC_SIGBUS))
+#else  /* CONFIG_ALPHA_UAC_SYSCTL */
+   if (enabled_sigbus)
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */
 		goto give_sigbus;
 	/* Not sure why you'd want to use this, but... */
+#ifndef CONFIG_ALPHA_UAC_SYSCTL
 	if (test_thread_flag (TIF_UAC_NOFIX))
+#else  /* CONFIG_ALPHA_UAC_SYSCTL */
+   if (enabled_nofix)
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */
 		return;
 
 	/* Don't bother reading ds in the access check since we already
@@ -1089,3 +1147,7 @@ trap_init(void)
 	wrent(entSys, 5);
 	wrent(entDbg, 6);
 }
+
+#ifdef CONFIG_ALPHA_UAC_SYSCTL
+	__initcall(init_uac_sysctl);
+#endif
--- src/kernel/sysctl.c.orig	2008-04-11 19:26:51.000000000 -0400
+++ src/kernel/sysctl.c	2008-04-13 16:35:12.000000000 -0400
@@ -168,6 +168,9 @@ extern struct ctl_table random_table[];
 #ifdef CONFIG_INOTIFY_USER
 extern struct ctl_table inotify_table[];
 #endif
+#ifdef CONFIG_ALPHA_UAC_SYSCTL
+extern struct ctl_table uac_table[];
+#endif
 
 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 int sysctl_legacy_va_layout;
@@ -779,6 +782,14 @@ static struct ctl_table kern_table[] = {
  * NOTE: do not add new entries to this table unless you have read
  * Documentation/sysctl/ctl_unnumbered.txt
  */
+#ifdef CONFIG_ALPHA_UAC_SYSCTL
+    {
+        .ctl_name   = CTL_UNNUMBERED,
+        .procname   = "uac",
+        .mode       = 0555,
+        .child      = uac_table,
+    },
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */
 	{ .ctl_name = 0 }
 };