| 1 |
--- |
| 2 |
arch/alpha/Kconfig | 26 ++++++++++++++++++++++++ |
| 3 |
arch/alpha/kernel/traps.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++ |
| 4 |
include/linux/sysctl.h | 14 +++++++++++++ |
| 5 |
kernel/sysctl.c | 12 ++++++++++- |
| 6 |
4 files changed, 100 insertions(+), 1 deletion(-) |
| 7 |
|
| 8 |
--- a/arch/alpha/Kconfig |
| 9 |
+++ b/arch/alpha/Kconfig |
| 10 |
@@ -616,6 +616,32 @@ config VERBOSE_MCHECK_ON |
| 11 |
|
| 12 |
Take the default (1) unless you want more control or more info. |
| 13 |
|
| 14 |
+config ALPHA_UAC_SYSCTL |
| 15 |
+ bool "Configure UAC policy via sysctl" |
| 16 |
+ depends on SYSCTL |
| 17 |
+ default y |
| 18 |
+ ---help--- |
| 19 |
+ Configuring the UAC (unaligned access control) policy on a Linux |
| 20 |
+ system usually involves setting a compile time define. If you say |
| 21 |
+ Y here, you will be able to modify the UAC policy at runtime using |
| 22 |
+ the /proc interface. |
| 23 |
+ |
| 24 |
+ The UAC policy defines the action Linux should take when an |
| 25 |
+ unaligned memory access occurs. The action can include printing a |
| 26 |
+ warning message (NOPRINT), sending a signal to the offending |
| 27 |
+ program to help developers debug their applications (SIGBUS), or |
| 28 |
+ disabling the transparent fixing (NOFIX). |
| 29 |
+ |
| 30 |
+ The sysctls will be initialized to the compile-time defined UAC |
| 31 |
+ policy. You can change these manually, or with the sysctl(8) |
| 32 |
+ userspace utility. |
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+ |
| 34 |
+ To disable the warning messages at runtime, you would use |
| 35 |
+ |
| 36 |
+ echo 1 > /proc/sys/kernel/uac/noprint |
| 37 |
+ |
| 38 |
+ This is pretty harmless. Say Y if you're not sure. |
| 39 |
+ |
| 40 |
source "drivers/pci/Kconfig" |
| 41 |
source "drivers/eisa/Kconfig" |
| 42 |
|
| 43 |
--- a/arch/alpha/kernel/traps.c |
| 44 |
+++ b/arch/alpha/kernel/traps.c |
| 45 |
@@ -14,6 +14,7 @@ |
| 46 |
#include <linux/delay.h> |
| 47 |
#include <linux/smp_lock.h> |
| 48 |
#include <linux/module.h> |
| 49 |
+#include <linux/sysctl.h> |
| 50 |
#include <linux/init.h> |
| 51 |
#include <linux/kallsyms.h> |
| 52 |
|
| 53 |
@@ -102,6 +103,38 @@ static char * ireg_name[] = {"v0", "t0", |
| 54 |
"t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"}; |
| 55 |
#endif |
| 56 |
|
| 57 |
+#ifdef CONFIG_ALPHA_UAC_SYSCTL |
| 58 |
+static struct ctl_table_header *uac_sysctl_header; |
| 59 |
+ |
| 60 |
+static int enabled_noprint = 0; |
| 61 |
+static int enabled_sigbus = 0; |
| 62 |
+static int enabled_nofix = 0; |
| 63 |
+ |
| 64 |
+ctl_table uac_table[] = { |
| 65 |
+ {KERN_UAC_NOPRINT, "noprint", &enabled_noprint, sizeof (int), 0644, NULL, NULL, &proc_dointvec}, |
| 66 |
+ {KERN_UAC_SIGBUS, "sigbus", &enabled_sigbus, sizeof (int), 0644, NULL, NULL, &proc_dointvec}, |
| 67 |
+ {KERN_UAC_NOFIX, "nofix", &enabled_nofix, sizeof (int), 0644, NULL, NULL, &proc_dointvec}, |
| 68 |
+ {0} |
| 69 |
+}; |
| 70 |
+ |
| 71 |
+static int __init init_uac_sysctl(void) |
| 72 |
+{ |
| 73 |
+ /* Initialize sysctls with the #defined UAC policy */ |
| 74 |
+ enabled_noprint = (test_thread_flag (TIF_UAC_NOPRINT)) ? 1 : 0; |
| 75 |
+ enabled_sigbus = (test_thread_flag (TIF_UAC_SIGBUS)) ? 1 : 0; |
| 76 |
+ enabled_nofix = (test_thread_flag (TIF_UAC_NOFIX)) ? 1 : 0; |
| 77 |
+ |
| 78 |
+ /* save this for later so we can clean up */ |
| 79 |
+ uac_sysctl_header = register_sysctl_table(uac_table); |
| 80 |
+ return 0; |
| 81 |
+} |
| 82 |
+ |
| 83 |
+static void __exit exit_uac_sysctl(void) |
| 84 |
+{ |
| 85 |
+ unregister_sysctl_table(uac_sysctl_header); |
| 86 |
+} |
| 87 |
+#endif |
| 88 |
+ |
| 89 |
static void |
| 90 |
dik_show_code(unsigned int *pc) |
| 91 |
{ |
| 92 |
@@ -780,7 +813,11 @@ do_entUnaUser(void __user * va, unsigned |
| 93 |
/* Check the UAC bits to decide what the user wants us to do |
| 94 |
with the unaliged access. */ |
| 95 |
|
| 96 |
+#ifndef CONFIG_ALPHA_UAC_SYSCTL |
| 97 |
if (!test_thread_flag (TIF_UAC_NOPRINT)) { |
| 98 |
+#else /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 99 |
+ if (!(enabled_noprint)) { |
| 100 |
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 101 |
if (cnt >= 5 && jiffies - last_time > 5*HZ) { |
| 102 |
cnt = 0; |
| 103 |
} |
| 104 |
@@ -791,10 +828,18 @@ do_entUnaUser(void __user * va, unsigned |
| 105 |
} |
| 106 |
last_time = jiffies; |
| 107 |
} |
| 108 |
+#ifndef CONFIG_ALPHA_UAC_SYSCTL |
| 109 |
if (test_thread_flag (TIF_UAC_SIGBUS)) |
| 110 |
+#else /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 111 |
+ if (enabled_sigbus) |
| 112 |
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 113 |
goto give_sigbus; |
| 114 |
/* Not sure why you'd want to use this, but... */ |
| 115 |
+#ifndef CONFIG_ALPHA_UAC_SYSCTL |
| 116 |
if (test_thread_flag (TIF_UAC_NOFIX)) |
| 117 |
+#else /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 118 |
+ if (enabled_nofix) |
| 119 |
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 120 |
return; |
| 121 |
|
| 122 |
/* Don't bother reading ds in the access check since we already |
| 123 |
@@ -1089,3 +1134,7 @@ trap_init(void) |
| 124 |
wrent(entSys, 5); |
| 125 |
wrent(entDbg, 6); |
| 126 |
} |
| 127 |
+ |
| 128 |
+#ifdef CONFIG_ALPHA_UAC_SYSCTL |
| 129 |
+__initcall(init_uac_sysctl); |
| 130 |
+#endif |
| 131 |
--- a/include/linux/sysctl.h |
| 132 |
+++ b/include/linux/sysctl.h |
| 133 |
@@ -166,6 +166,9 @@ enum |
| 134 |
KERN_NMI_WATCHDOG=75, /* int: enable/disable nmi watchdog */ |
| 135 |
KERN_PANIC_ON_NMI=76, /* int: whether we will panic on an unrecovered */ |
| 136 |
KERN_FBCON_DECOR=77, /* string: path to fbsplash helper */ |
| 137 |
+#ifdef CONFIG_ALPHA_UAC_SYSCTL |
| 138 |
+ KERN_UAC_POLICY=78, /* int: Alpha unaligned access control policy flags */ |
| 139 |
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 140 |
}; |
| 141 |
|
| 142 |
|
| 143 |
@@ -259,6 +262,17 @@ enum |
| 144 |
PTY_NR=2 |
| 145 |
}; |
| 146 |
|
| 147 |
+#ifdef CONFIG_ALPHA_UAC_SYSCTL |
| 148 |
+/* /proc/sys/kernel/uac */ |
| 149 |
+enum |
| 150 |
+{ |
| 151 |
+ /* UAC policy on Alpha */ |
| 152 |
+ KERN_UAC_NOPRINT=1, /* int: printk() on unaligned access */ |
| 153 |
+ KERN_UAC_SIGBUS=2, /* int: send SIGBUS on unaligned access */ |
| 154 |
+ KERN_UAC_NOFIX=3, /* int: don't fix the unaligned access */ |
| 155 |
+}; |
| 156 |
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 157 |
+ |
| 158 |
/* /proc/sys/bus/isa */ |
| 159 |
enum |
| 160 |
{ |
| 161 |
--- a/kernel/sysctl.c |
| 162 |
+++ b/kernel/sysctl.c |
| 163 |
@@ -158,6 +158,9 @@ extern ctl_table pty_table[]; |
| 164 |
#ifdef CONFIG_INOTIFY_USER |
| 165 |
extern ctl_table inotify_table[]; |
| 166 |
#endif |
| 167 |
+#ifdef CONFIG_ALPHA_UAC_SYSCTL |
| 168 |
+extern ctl_table uac_table[]; |
| 169 |
+#endif |
| 170 |
|
| 171 |
#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT |
| 172 |
int sysctl_legacy_va_layout; |
| 173 |
@@ -211,6 +214,14 @@ static ctl_table root_table[] = { |
| 174 |
* NOTE: do not add new entries to this table unless you have read |
| 175 |
* Documentation/sysctl/ctl_unnumbered.txt |
| 176 |
*/ |
| 177 |
+#ifdef CONFIG_ALPHA_UAC_SYSCTL |
| 178 |
+ { |
| 179 |
+ .ctl_name = KERN_UAC_POLICY, |
| 180 |
+ .procname = "uac", |
| 181 |
+ .mode = 0555, |
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+ .child = uac_table, |
| 183 |
+ }, |
| 184 |
+#endif /* CONFIG_ALPHA_UAC_SYSCTL */ |
| 185 |
{ .ctl_name = 0 } |
| 186 |
}; |
| 187 |
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