Setting and ->psw.addr in childregs of kernel thread is a rudiment of
the old kernel_thread()/kernel_execve() implementation. Mainline hadn't
been using them since 2012.
And clarify the assigments to frame->sf.gprs - the array stores grp6..gpr15
values to be set by __switch_to(), so frame->sf.gprs[5] actually affects
grp11, etc. Better spell that as frame->sf.gprs[11 - 6]...
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 67df64ef4839..87ca3a727604 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -136,12 +136,12 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
p->thread.last_break = 1;
frame->sf.back_chain = 0;
- frame->sf.gprs[5] = (unsigned long)frame + sizeof(struct stack_frame);
- frame->sf.gprs[6] = (unsigned long)p;
+ frame->sf.gprs[11 - 6] = (unsigned long)&frame->childregs;
+ frame->sf.gprs[12 - 6] = (unsigned long)p;
/* new return point is ret_from_fork */
- frame->sf.gprs[8] = (unsigned long)ret_from_fork;
+ frame->sf.gprs[14 - 6] = (unsigned long)ret_from_fork;
/* fake return stack for resume(), don't go back to schedule */
- frame->sf.gprs[9] = (unsigned long)frame;
+ frame->sf.gprs[15 - 6] = (unsigned long)frame;
/* Store access registers to kernel stack of new process. */
if (unlikely(args->fn)) {
@@ -149,8 +149,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
memset(&frame->childregs, 0, sizeof(struct pt_regs));
frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO |
PSW_MASK_EXT | PSW_MASK_MCHECK;
- frame->childregs.psw.addr =
- (unsigned long)__ret_from_fork;
frame->childregs.gprs[9] = (unsigned long)args->fn;
frame->childregs.gprs[10] = (unsigned long)args->fn_arg;
frame->childregs.orig_gpr2 = -1;
