From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751443AbdKUO0z (ORCPT ); Tue, 21 Nov 2017 09:26:55 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:59408 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751302AbdKUO0y (ORCPT ); Tue, 21 Nov 2017 09:26:54 -0500 From: Christophe Leroy Subject: [PATCH v2] powerpc: fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Message-Id: <20171121142647.5A79A6BB8F@po15668-vm-win7.idsi0.si.c-s.fr> Date: Tue, 21 Nov 2017 15:26:47 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On powerpc32, patch_instruction() is called by apply_feature_fixups() which is called from early_init() There is the following note in front of early_init(): * Note that the kernel may be running at an address which is different * from the address that it was linked at, so we must use RELOC/PTRRELOC * to access static data (including strings). -- paulus Therefore, slab_is_available() cannot be called yet, and text_poke_area must be addressed with PTRRELOC() Fixes: 37bc3e5fd764f ("powerpc/lib/code-patching: Use alternate map for patch_instruction()") Reported-by: Meelis Roos Cc: Balbir Singh Signed-off-by: Christophe Leroy --- v2: Added missing asm/setup.h arch/powerpc/lib/code-patching.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index c9de03e0c1f1..d469224c4ada 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -21,6 +21,7 @@ #include #include #include +#include static int __patch_instruction(unsigned int *addr, unsigned int instr) { @@ -146,11 +147,8 @@ int patch_instruction(unsigned int *addr, unsigned int instr) * During early early boot patch_instruction is called * when text_poke_area is not ready, but we still need * to allow patching. We just do the plain old patching - * We use slab_is_available and per cpu read * via this_cpu_read - * of text_poke_area. Per-CPU areas might not be up early - * this can create problems with just using this_cpu_read() */ - if (!slab_is_available() || !this_cpu_read(text_poke_area)) + if (!this_cpu_read(*PTRRELOC(&text_poke_area))) return __patch_instruction(addr, instr); local_irq_save(flags); -- 2.13.3