sysctl: Enable PARISC "unaligned-trap" to be used cross-arch

PARISC defines /proc/sys/kernel/unaligned-trap to runtime toggle
unaligned access emulation.

The exact mechanics of enablig/disabling are still arch specific, we can
make the sysctl usable by other arches.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index b77feff..8c76095 100644 (file)
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -20,6 +20,7 @@ config PARISC
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select GENERIC_SMP_IDLE_THREAD
        select GENERIC_STRNCPY_FROM_USER
+       select SYSCTL_ARCH_UNALIGN_ALLOW
        select HAVE_MOD_ARCH_SPECIFIC
        select MODULES_USE_ELF_RELA
        select CLONE_BACKWARDS

diff --git a/init/Kconfig b/init/Kconfig
index be8b7f5..01180da 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1232,6 +1232,14 @@ config SYSCTL_EXCEPTION_TRACE
        help
          Enable support for /proc/sys/debug/exception-trace.
 
+config SYSCTL_ARCH_UNALIGN_ALLOW
+       bool
+       help
+         Enable support for /proc/sys/kernel/unaligned-trap
+         Allows arches to define/use @unaligned_enabled to runtime toggle
+         the unaligned access emulation.
+         see arch/parisc/kernel/unaligned.c for reference
+
 config KALLSYMS
         bool "Load all symbols for debugging/ksymoops" if EXPERT
         default y

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c88878d..878b4c4 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -157,6 +157,9 @@ extern int sysctl_tsb_ratio;
 
 #ifdef __hppa__
 extern int pwrsw_enabled;
+#endif
+
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
 extern int unaligned_enabled;
 #endif
 
@@ -545,6 +548,8 @@ static struct ctl_table kern_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
+#endif
+#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
        {
                .procname       = "unaligned-trap",
                .data           = &unaligned_enabled,