commit 10d54d1601ede2f2bc7b6a1dd10c09e52d340b95
author Andrew Ermakovich <andrew@resilio.com> Fri May 05 11:49:45 2017 +0300
committer Mark Seaborn <mseaborn@chromium.org> Wed May 10 00:34:42 2017 +0000
tree b42365a9c5516c1e7e556c724ea46bccc4889801
parent 63f24c8221a229f677d26ebe8f3d1528a9d787ac

Fix sys_clone() for thumb2.

Sometimes compiler take r7 register for output operand __res because there is no r7 register
in clobber registers for thumb2. And after assign "movs  %0, r0\n" sys_clone() call "pop {r7}". 
As result _res is corrupted by "pop".

Bug: linux-syscall-support:19

Change-Id: Ia5b56ebe3beb11585ac043738f70f9724c6f9e8d
Reviewed-on: https://chromium-review.googlesource.com/485499
Reviewed-by: Mark Seaborn <mseaborn@chromium.org>

linux_syscall_support.h

diff --git a/linux_syscall_support.h b/linux_syscall_support.h
index 80a3e56..c3f4584 100644
--- a/linux_syscall_support.h
+++ b/linux_syscall_support.h
@@ -2624,7 +2624,7 @@
                              /* if (%r0 != 0)
                               *   return %r0;
                               */
-                             "movs  %0,r0\n"
+                             "cmp   r0, #0\n"
                              "bne   1f\n"
 
                              /* In the child, now. Call "fn(arg)".
@@ -2655,8 +2655,9 @@
                              "swi 0x0\n"
                            "1:\n"
 #ifdef __thumb2__
-                             "pop {r7}"
+                             "pop {r7}\n"
 #endif
+                             "mov %0, r0"
                              : "=r" (__res)
                              : "r"(fn), "r"(__stack), "r"(__flags), "r"(arg),
                                "r"(__ptid), "r"(__tls), "r"(__ctid),