Fix inadvertent breakage in the clone syscall ABI for Microblaze that was introduced in this patch: "microblaze: switch to generic fork/vfork/clone" (sha1: f3268edbe6fe0ce56e62c6d6b14640aeb04864b7)
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>
---
Changes in v3:
- Change patch description based on Rich comments.
Changes in v2:
- Add information about the first broken patch - Suggested by Andrew
arch/Kconfig | 6 ++++++
arch/microblaze/Kconfig | 2 +-
include/linux/syscalls.h | 5 +++++
kernel/fork.c | 6 ++++++
4 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 8d2ae24..1feb169 100644
--- a/arch/Kconfig
+++ b/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 --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index d22a4ec..4fab522 100644
--- 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
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 4147d70..71d8931 100644
--- 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
+#if 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 --git a/kernel/fork.c b/kernel/fork.c
index 403d2bb..e23bb19 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1679,6 +1679,12 @@ SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned
long, clone_flags,
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,
--
1.8.2.3
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