c6x: sanitize copy_thread(), get rid of clone(2) wrapper, switch to generic clone()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 6 insertions, 36 deletions

diff --git a/arch/c6x/include/asm/syscalls.h b/arch/c6x/include/asm/syscalls.h
index e7b8991dc07c..df3d05feb153 100644
--- a/arch/c6x/include/asm/syscalls.h
+++ b/arch/c6x/include/asm/syscalls.h
@@ -41,10 +41,6 @@ extern long sys_fallocate_c6x(int fd, int mode,
                               u32 len_lo, u32 len_hi);
 extern int sys_cache_sync(unsigned long s, unsigned long e);
 
-struct pt_regs;
-
-extern asmlinkage long sys_c6x_clone(struct pt_regs *regs);
-
 #include <asm-generic/syscalls.h>
 
 #endif /* __ASM_C6X_SYSCALLS_H */
diff --git a/arch/c6x/include/uapi/asm/unistd.h b/arch/c6x/include/uapi/asm/unistd.h
index 625beafb9cd1..f3987a8703d9 100644
--- a/arch/c6x/include/uapi/asm/unistd.h
+++ b/arch/c6x/include/uapi/asm/unistd.h
@@ -15,6 +15,7 @@
  */
 
 #define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_CLONE
 
 /* Use the standard ABI for syscalls. */
 #include <asm-generic/unistd.h>
diff --git a/arch/c6x/kernel/entry.S b/arch/c6x/kernel/entry.S
index 75f6f36472cf..1037b98953ca 100644
--- a/arch/c6x/kernel/entry.S
+++ b/arch/c6x/kernel/entry.S
@@ -613,18 +613,6 @@ ENDPROC(sys_sigaltstack)
         ;; Special system calls
         ;; return address is in B3
         ;;
-ENTRY(sys_clone)
-        ADD     .D1X    SP,8,A4
-#ifdef CONFIG_C6X_BIG_KERNEL
- ||     MVKL    .S1     sys_c6x_clone,A0
-        MVKH    .S1     sys_c6x_clone,A0
-        BNOP    .S2X    A0,5
-#else
- ||     B       .S2     sys_c6x_clone
-        NOP     5
-#endif
-ENDPROC(sys_clone)
-
 ENTRY(sys_rt_sigreturn)
         ADD     .D1X    SP,8,A4
 #ifdef CONFIG_C6X_BIG_KERNEL
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
index 2770d9a9a84e..a3f91895e8b4 100644
--- a/arch/c6x/kernel/process.c
+++ b/arch/c6x/kernel/process.c
@@ -112,22 +112,6 @@ void exit_thread(void)
 {
 }
 
-SYSCALL_DEFINE1(c6x_clone, struct pt_regs *, regs)
-{
-        unsigned long clone_flags;
-        unsigned long newsp;
-
-        /* syscall puts clone_flags in A4 and usp in B4 */
-        clone_flags = regs->orig_a4;
-        if (regs->b4)
-                newsp = regs->b4;
-        else
-                newsp = regs->sp;
-
-        return do_fork(clone_flags, newsp, regs, 0, (int __user *)regs->a6,
-                       (int __user *)regs->b6);
-}
-
 /*
  * Do necessary setup to start up a newly executed thread.
  */
@@ -155,13 +139,13 @@ void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
  */
 int copy_thread(unsigned long clone_flags, unsigned long usp,
                 unsigned long ustk_size,
-                struct task_struct *p, struct pt_regs *regs)
+                struct task_struct *p, struct pt_regs *unused)
 {
         struct pt_regs *childregs;
 
         childregs = task_pt_regs(p);
 
-        if (!regs) {
+        if (unlikely(p->flags & PF_KTHREAD)) {
                 /* case of  __kernel_thread: we return to supervisor space */
                 memset(childregs, 0, sizeof(struct pt_regs));
                 childregs->sp = (unsigned long)(childregs + 1);
@@ -170,8 +154,9 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
                 childregs->a1 = ustk_size;      /* argument */
         } else {
                 /* Otherwise use the given stack */
-                *childregs = *regs;
-                childregs->sp = usp;
+                *childregs = *current_pt_regs();
+                if (usp)
+                        childregs->sp = usp;
                 p->thread.pc = (unsigned long) ret_from_fork;
         }