From: Michal Simek <michal.simek@xxxxxxxxxx>
Subject: microblaze: fix clone syscall
Fix inadvertent breakage in the clone syscall ABI for Microblaze that was
introduced in f3268edb ("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.simek@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/Kconfig | 6 ++++++
arch/microblaze/Kconfig | 2 +-
include/linux/syscalls.h | 5 +++++
kernel/fork.c | 6 ++++++
4 files changed, 18 insertions(+), 1 deletion(-)
diff -puN arch/Kconfig~microblaze-fix-clone-syscall arch/Kconfig
--- a/arch/Kconfig~microblaze-fix-clone-syscall
+++ a/arch/Kconfig
@@ -407,6 +407,12 @@ 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
diff -puN arch/microblaze/Kconfig~microblaze-fix-clone-syscall arch/microblaze/Kconfig
--- a/arch/microblaze/Kconfig~microblaze-fix-clone-syscall
+++ a/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
diff -puN include/linux/syscalls.h~microblaze-fix-clone-syscall include/linux/syscalls.h
--- a/include/linux/syscalls.h~microblaze-fix-clone-syscall
+++ a/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,
diff -puN kernel/fork.c~microblaze-fix-clone-syscall kernel/fork.c
--- a/kernel/fork.c~microblaze-fix-clone-syscall
+++ a/kernel/fork.c
@@ -1679,6 +1679,12 @@ 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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