From: Nicholas Piggin <npiggin@gmail.com>
Date: Sat, 25 Mar 2023 12:28:57 +0000 (+1000)
Subject: powerpc: copy_thread remove unused pkey code
X-Git-Tag: v6.6.7~2957^2~101
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c013e9f2bbe1d2be5e1c7f4a84216cd10837f20d;p=platform%2Fkernel%2Flinux-starfive.git

powerpc: copy_thread remove unused pkey code

The pkey registers (AMR, IAMR) do not get loaded from the switch frame
so it is pointless to save anything there. Remove the dead code.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230325122904.2375060-2-npiggin@gmail.com
---

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index a7f9f3f..7fe7003 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1813,6 +1813,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 	sp -= STACK_SWITCH_FRAME_SIZE;
 	((unsigned long *)sp)[0] = sp + STACK_SWITCH_FRAME_SIZE;
 	kregs = (struct pt_regs *)(sp + STACK_SWITCH_FRAME_REGS);
+	kregs->nip = ppc_function_entry(f);
 	p->thread.ksp = sp;
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -1845,17 +1846,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
 	p->thread.tidr = 0;
 #endif
-	/*
-	 * Run with the current AMR value of the kernel
-	 */
-#ifdef CONFIG_PPC_PKEY
-	if (mmu_has_feature(MMU_FTR_BOOK3S_KUAP))
-		kregs->amr = AMR_KUAP_BLOCKED;
-
-	if (mmu_has_feature(MMU_FTR_BOOK3S_KUEP))
-		kregs->iamr = AMR_KUEP_BLOCKED;
-#endif
-	kregs->nip = ppc_function_entry(f);
 	return 0;
 }