3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Simek <michal.si...@xilinx.com>

commit dfa9771a7c4784bafd0673bc7abcee3813088b77 upstream.

Fix inadvertent breakage in the clone syscall ABI for Microblaze that
was introduced in commit f3268edbe6fe ("microblaze: switch to generic
fork/vfork/clone").

The Microblaze syscall ABI for clone takes the parent tid address in the
4th argument; the third argument slot is used for the stack size.  The
incorrectly-used CLONE_BACKWARDS type assigned parent tid to the 3rd
slot.

This commit restores the original ABI so that existing userspace libc
code will work correctly.

All kernel versions from v3.8-rc1 were affected.

Signed-off-by: Michal Simek <michal.si...@xilinx.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 arch/Kconfig             |    6 ++++++
 arch/microblaze/Kconfig  |    2 +-
 include/linux/syscalls.h |    5 +++++
 kernel/fork.c            |    6 ++++++
 4 files changed, 18 insertions(+), 1 deletion(-)

--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -404,6 +404,12 @@ config CLONE_BACKWARDS2
        help
          Architecture has the first two arguments of clone(2) swapped.
 
+config CLONE_BACKWARDS3
+       bool
+       help
+         Architecture has tls passed as the 3rd argument of clone(2),
+         not the 5th one.
+
 config ODD_RT_SIGACTION
        bool
        help
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -28,7 +28,7 @@ config MICROBLAZE
        select GENERIC_CLOCKEVENTS
        select GENERIC_IDLE_POLL_SETUP
        select MODULES_USE_ELF_RELA
-       select CLONE_BACKWARDS
+       select CLONE_BACKWARDS3
 
 config SWAP
        def_bool n
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -802,9 +802,14 @@ asmlinkage long sys_vfork(void);
 asmlinkage long sys_clone(unsigned long, unsigned long, int __user *, int,
               int __user *);
 #else
+#ifdef CONFIG_CLONE_BACKWARDS3
+asmlinkage long sys_clone(unsigned long, unsigned long, int, int __user *,
+                         int __user *, int);
+#else
 asmlinkage long sys_clone(unsigned long, unsigned long, int __user *,
               int __user *, int);
 #endif
+#endif
 
 asmlinkage long sys_execve(const char __user *filename,
                const char __user *const __user *argv,
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1675,6 +1675,12 @@ SYSCALL_DEFINE5(clone, unsigned long, ne
                 int __user *, parent_tidptr,
                 int __user *, child_tidptr,
                 int, tls_val)
+#elif defined(CONFIG_CLONE_BACKWARDS3)
+SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp,
+               int, stack_size,
+               int __user *, parent_tidptr,
+               int __user *, child_tidptr,
+               int, tls_val)
 #else
 SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
                 int __user *, parent_tidptr,


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