From patchwork Fri Apr 22 11:12:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Vivier X-Patchwork-Id: 613550 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3qrtHx3qkCz9t3V for ; Fri, 22 Apr 2016 21:12:29 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753934AbcDVLMS (ORCPT ); Fri, 22 Apr 2016 07:12:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36464 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751897AbcDVLMP (ORCPT ); Fri, 22 Apr 2016 07:12:15 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 035F681106; Fri, 22 Apr 2016 11:12:14 +0000 (UTC) Received: from thinkpad.redhat.com (ovpn-112-54.ams2.redhat.com [10.36.112.54]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u3MBCA7k026337; Fri, 22 Apr 2016 07:12:11 -0400 From: Laurent Vivier To: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, thuth@redhat.com Cc: drjones@redhat.com, dgibson@redhat.com, pbonzini@redhat.com, Laurent Vivier Subject: [kvm-unit-tests PATCH v2] powerpc: restore TOC pointer Date: Fri, 22 Apr 2016 13:12:07 +0200 Message-Id: <1461323527-20148-1-git-send-email-lvivier@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org As the TOC pointer can be corrupted by the main program, we must restore it in the exception handler. As we know where we are loaded, we can now compute it easily. To compute it only in the common part of the exception handler (call_handler), store the address of call_handler at an absolute address in memory to be able to call the handler from the exception table (as SLOF does). Reported-by: Thomas Huth Signed-off-by: Laurent Vivier --- v2: don't add SPAPR_KERNEL_LOAD_ADDR to r2 as the TOC has been relocated and have directly the good value. The problem has been reported by Thomas. powerpc/cstart64.S | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S index c47b67d..2d66032 100644 --- a/powerpc/cstart64.S +++ b/powerpc/cstart64.S @@ -13,6 +13,8 @@ #include "spapr.h" +#define P_HANDLER 0x2ff8 + .section .init /* @@ -46,6 +48,11 @@ start: add r4, r4, r31 bl relocate + /* compute address of call_handler */ + + LOAD_REG_ADDR(r4, call_handler) + std r4, P_HANDLER(0) + /* relocate vector table to base address 0x0 (MSR_IP = 0) */ /* source: r4, dest end: r5, destination: r6 */ @@ -166,6 +173,11 @@ call_handler: mfsrr1 r0 std r0, _MSR(r1) + /* restore TOC pointer */ + + LOAD_REG_IMMEDIATE(r31, SPAPR_KERNEL_LOAD_ADDR) + ld r2, (p_toc - start)(r31) + /* FIXME: build stack frame */ /* call generic handler */ @@ -221,7 +233,7 @@ call_handler: mfctr r0 std r0,_CTR(r1) - LOAD_REG_ADDR(r0, call_handler) + ld r0, P_HANDLER(0) mtctr r0 li r0,\vec @@ -245,3 +257,5 @@ VECTOR(0x900) .align 7 .globl __end_interrupts __end_interrupts: + .org P_HANDLER + .llong 0