[patch] UAC Alpha patch

4400_alpha-sysctl-uac.patch (text/plain), 4.55 KB, created by Mike Pagano on 2010-03-15 18:49:50 UTC

Index: linux-2.6.26-gentoo/arch/alpha/Kconfig
===================================================================
--- linux-2.6.26-gentoo.orig/arch/alpha/Kconfig
+++ linux-2.6.26-gentoo/arch/alpha/Kconfig
@@ -624,6 +624,32 @@ config HZ
 	default 1200 if ALPHA_RAWHIDE
 	default 1024
 
+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"
 
Index: linux-2.6.26-gentoo/arch/alpha/kernel/traps.c
===================================================================
--- linux-2.6.26-gentoo.orig/arch/alpha/kernel/traps.c
+++ linux-2.6.26-gentoo/arch/alpha/kernel/traps.c
@@ -103,6 +103,52 @@ 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)
 {
@@ -782,7 +828,11 @@ 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 && time_after(jiffies, last_time + 5 * HZ)) {
 			cnt = 0;
 		}
@@ -793,10 +843,18 @@ 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
@@ -1091,3 +1149,7 @@ trap_init(void)
 	wrent(entSys, 5);
 	wrent(entDbg, 6);
 }
+
+#ifdef CONFIG_ALPHA_UAC_SYSCTL
+	__initcall(init_uac_sysctl);
+#endif
Index: linux-2.6.26-gentoo/kernel/sysctl.c
===================================================================
--- a/kernel/sysctl.c	2010-03-15 14:22:31.000000000 -0400
+++ b/kernel/sysctl.c	2010-03-15 14:34:52.000000000 -0400
@@ -239,6 +239,14 @@ static struct ctl_table root_table[] = {
 	{ }
 };
 
+#ifdef CONFIG_ALPHA_UAC_SYSCTL
+    {
+        .procname   = "uac",
+        .mode       = 0555,
+        .child      = uac_table,
+    },
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */
+
 #ifdef CONFIG_SCHED_DEBUG
 static int min_sched_granularity_ns = 100000;		/* 100 usecs */
 static int max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */