Subject: [PATCH 2/8] powerpc: copy_thread make ret_from_fork register setup consistent

From: Nicholas Piggin <[email-masked]>
Date: Wed, 1 Feb 2023 02:55:28 +1000

The ret_from_fork code for 64e and 32-bit set r3 for
syscall_exit_prepare the same way that 64s does, so there should be no
need to special-case them in copy_thread.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/entry_32.S | 2 +-
 arch/powerpc/kernel/process.c  | 3 ---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 5604c9a1ac22..755408c63be8 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -183,7 +183,7 @@ syscall_exit_finish:
 ret_from_fork:
 	REST_NVGPRS(r1)
 	bl	schedule_tail
-	li	r3,0
+	li	r3,0	/* fork() return value */
 	b	ret_from_syscall
 
 	.globl	ret_from_kernel_thread
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index ba10505f62c1..dc66ca668b44 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1785,9 +1785,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 			childregs->gpr[1] = usp;
 		((unsigned long *)sp)[0] = childregs->gpr[1];
 		p->thread.regs = childregs;
-		/* 64s sets this in ret_from_fork */
-		if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
-			childregs->gpr[3] = 0;  /* Result from fork() */
 		if (clone_flags & CLONE_SETTLS) {
 			if (!is_32bit_task())
 				childregs->gpr[13] = tls;
-- 
2.37.2