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().

Cc: <stable@vger.kernel.org>
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>

Provide an ARM implementation of syscall_get_arch. This is a pre-requisite
for CONFIG_HAVE_ARCH_SECCOMP_FILTER.

Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

The syscall tracing patch introduces a compile bug in lttng-modules
when the latter calls syscall_get_nr(), similar to the following:

<path-to-linux>/arch/arm/include/asm/syscall.h:21:2: error: implicit declaration of function 'task_thread_info' [-Werror=implicit-function-declaration]

The issue is that we are using task_thread_info() in the
syscall_get_nr() function in asm/syscall.h, but not explicitly
including sched.h from this file, so we can expect this bug might
surface any time that syscall_get_nr() is called.

Explicitly including sched.h solves the problem.

Cc: <stable@vger.kernel.org> [3.5, 3.6]
Signed-off-by: Wade Farnsworth <wade_farnsworth@mentor.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
added, as well as NR_syscalls in asm/unistd.h.  Additionally,
__sys_trace was modified to call trace_sys_enter and
trace_sys_exit when appropriate.

Tests #2 - #4 of "perf test" now complete successfully.

Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
Signed-off-by: Wade Farnsworth <wade_farnsworth@mentor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Supplying the asm-generic/syscall.h interface is a
pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by: Steven Walter <stevenrwalter@gmail.com>
Signed-off-by: Wade Farnsworth <wade_farnsworth@mentor.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>