powerpc: put the "zero usp means using parent's stack pointer" to copy_thread()

simplifies callers, at that...

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

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index de9f032..3665d28 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -761,7 +761,8 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
        } else {
                CHECK_FULL_REGS(regs);
                *childregs = *regs;
-               childregs->gpr[1] = usp;
+               if (usp)
+                       childregs->gpr[1] = usp;
                p->thread.regs = childregs;
                childregs->gpr[3] = 0;  /* Result from fork() */
                if (clone_flags & CLONE_SETTLS) {
@@ -1030,8 +1031,6 @@ int sys_clone(unsigned long clone_flags, unsigned long usp,
              int __user *child_tidp, int p6,
              struct pt_regs *regs)
 {
-       if (usp == 0)
-               usp = regs->gpr[1];     /* stack pointer for child */
        return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 }
 
@@ -1039,14 +1038,14 @@ int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
             unsigned long p4, unsigned long p5, unsigned long p6,
             struct pt_regs *regs)
 {
-       return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
+       return do_fork(SIGCHLD, 0, regs, 0, NULL, NULL);
 }
 
 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
              unsigned long p4, unsigned long p5, unsigned long p6,
              struct pt_regs *regs)
 {
-       return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
+       return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, 0,
                        regs, 0, NULL, NULL);
 }