Add ARM patch that was missed when adding the last batch of fixes

svn path=/dists/sid/linux/; revision=20769

debian/patches/bugfix/arm/arm-7851-1-check-for-number-of-arguments-in-syscall_get-set_arguments.patch

@@ -0,0 +1,53 @@
+From 3c1532df5c1b54b5f6246cdef94eeb73a39fe43a Mon Sep 17 00:00:00 2001
+From: AKASHI Takahiro <takahiro.akashi@linaro.org>
+Date: Wed, 9 Oct 2013 15:58:29 +0100
+Subject: ARM: 7851/1: check for number of arguments in syscall_get/set_arguments()
+
+From: AKASHI Takahiro <takahiro.akashi@linaro.org>
+
+commit 3c1532df5c1b54b5f6246cdef94eeb73a39fe43a upstream.
+
+In ftrace_syscall_enter(),
+    syscall_get_arguments(..., 0, n, ...)
+        if (i == 0) { <handle ORIG_r0> ...; n--;}
+        memcpy(..., n * sizeof(args[0]));
+If 'number of arguments(n)' is zero and 'argument index(i)' is also zero in
+syscall_get_arguments(), none of arguments should be copied by memcpy().
+Otherwise 'n--' can be a big positive number and unexpected amount of data
+will be copied. Tracing system calls which take no argument, say sync(void),
+may hit this case and eventually make the system corrupted.
+This patch fixes the issue both in syscall_get_arguments() and
+syscall_set_arguments().
+
+Acked-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
+Signed-off-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/arm/include/asm/syscall.h |    6 ++++++
+ 1 file changed, 6 insertions(+)
+
+--- a/arch/arm/include/asm/syscall.h
++++ b/arch/arm/include/asm/syscall.h
+@@ -57,6 +57,9 @@ static inline void syscall_get_arguments
+ 					 unsigned int i, unsigned int n,
+ 					 unsigned long *args)
+ {
++	if (n == 0)
++		return;
++
+ 	if (i + n > SYSCALL_MAX_ARGS) {
+ 		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
+ 		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
+@@ -81,6 +84,9 @@ static inline void syscall_set_arguments
+ 					 unsigned int i, unsigned int n,
+ 					 const unsigned long *args)
+ {
++	if (n == 0)
++		return;
++
+ 	if (i + n > SYSCALL_MAX_ARGS) {
+ 		pr_warning("%s called with max args %d, handling only %d\n",
+ 			   __func__, i + n, SYSCALL_MAX_ARGS);