[AGL] Apply the syscall restarting patch for aarch64 SoCflounder_6.0.3flounder/6.0.36.0.3

There are some seccomp bpf related failures when running kselftest
on R-Car M3(AGL inside).

Now, apply this patch to fix the syscall restart related bug(only
existing on kernel version < 4.14.53).

This patch won't be necessary if the kernel that AGL using was
changed to the latest ltsi(4.14.75) or kernel >= 4.14.53 in the future.

Change-Id: I1772d6f9d71c0903a605b5766bf217a46b2447c7
Signed-off-by: Liu Wenlong <liuwl.fnst@cn.fujitsu.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/meta-rcar-gen3/recipes-kernel/linux/linux-renesas/0001-arm64-Fix-syscall-restarting-around-signal-suppresse.patch b/meta-rcar-gen3/recipes-kernel/linux/linux-renesas/0001-arm64-Fix-syscall-restarting-around-signal-suppresse.patch
new file mode 100644
index 0000000..11159ff
--- /dev/null
+++ b/meta-rcar-gen3/recipes-kernel/linux/linux-renesas/0001-arm64-Fix-syscall-restarting-around-signal-suppresse.patch
@@ -0,0 +1,72 @@
+From 0fe42512b2f03f9e5a20b9f55ef1013a68b4cd48 Mon Sep 17 00:00:00 2001
+From: Dave Martin <Dave.Martin@arm.com>
+Date: Thu, 7 Jun 2018 12:32:05 +0100
+Subject: arm64: Fix syscall restarting around signal suppressed by tracer
+
+Commit 17c2895 ("arm64: Abstract syscallno manipulation") abstracts
+out the pt_regs.syscallno value for a syscall cancelled by a tracer
+as NO_SYSCALL, and provides helpers to set and check for this
+condition.  However, the way this was implemented has the
+unintended side-effect of disabling part of the syscall restart
+logic.
+
+This comes about because the second in_syscall() check in
+do_signal() re-evaluates the "in a syscall" condition based on the
+updated pt_regs instead of the original pt_regs.  forget_syscall()
+is explicitly called prior to the second check in order to prevent
+restart logic in the ret_to_user path being spuriously triggered,
+which means that the second in_syscall() check always yields false.
+
+This triggers a failure in
+tools/testing/selftests/seccomp/seccomp_bpf.c, when using ptrace to
+suppress a signal that interrups a nanosleep() syscall.
+
+Misbehaviour of this type is only expected in the case where a
+tracer suppresses a signal and the target process is either being
+single-stepped or the interrupted syscall attempts to restart via
+-ERESTARTBLOCK.
+
+This patch restores the old behaviour by performing the
+in_syscall() check only once at the start of the function.
+
+Fixes: 17c289586009 ("arm64: Abstract syscallno manipulation")
+Signed-off-by: Dave Martin <Dave.Martin@arm.com>
+Reported-by: Sumit Semwal <sumit.semwal@linaro.org>
+Cc: Will Deacon <will.deacon@arm.com>
+Cc: <stable@vger.kernel.org> # 4.14.x-
+Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
+---
+ arch/arm64/kernel/signal.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+(limited to 'arch/arm64/kernel/signal.c')
+
+diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
+index e7da5dba7ba8..511af13e8d8f 100644
+--- a/arch/arm64/kernel/signal.c
++++ b/arch/arm64/kernel/signal.c
+@@ -843,11 +843,12 @@ static void do_signal(struct pt_regs *regs)
+ 	unsigned long continue_addr = 0, restart_addr = 0;
+ 	int retval = 0;
+ 	struct ksignal ksig;
++	bool syscall = in_syscall(regs);
+ 
+ 	/*
+ 	 * If we were from a system call, check for system call restarting...
+ 	 */
+-	if (in_syscall(regs)) {
++	if (syscall) {
+ 		continue_addr = regs->pc;
+ 		restart_addr = continue_addr - (compat_thumb_mode(regs) ? 2 : 4);
+ 		retval = regs->regs[0];
+@@ -899,7 +900,7 @@ static void do_signal(struct pt_regs *regs)
+ 	 * Handle restarting a different system call. As above, if a debugger
+ 	 * has chosen to restart at a different PC, ignore the restart.
+ 	 */
+-	if (in_syscall(regs) && regs->pc == restart_addr) {
++	if (syscall && regs->pc == restart_addr) {
+ 		if (retval == -ERESTART_RESTARTBLOCK)
+ 			setup_restart_syscall(regs);
+ 		user_rewind_single_step(current);
+-- 
+cgit 1.2-0.3.lf.el7