From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A54C8C4338F for ; Tue, 24 Aug 2021 07:56:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C1D660F4A for ; Tue, 24 Aug 2021 07:56:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235083AbhHXH5W (ORCPT ); Tue, 24 Aug 2021 03:57:22 -0400 Received: from pegase2.c-s.fr ([93.17.235.10]:53147 "EHLO pegase2.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234969AbhHXH5V (ORCPT ); Tue, 24 Aug 2021 03:57:21 -0400 Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4Gv1dw4Pnkz9sVj; Tue, 24 Aug 2021 09:56:36 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uIG8z8ySajFn; Tue, 24 Aug 2021 09:56:36 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4Gv1dw39hBz9sTx; Tue, 24 Aug 2021 09:56:36 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4B31E8B7DA; Tue, 24 Aug 2021 09:56:36 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id MwG8-KYn4ZtM; Tue, 24 Aug 2021 09:56:36 +0200 (CEST) Received: from po18078vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 0B1BD8B7D1; Tue, 24 Aug 2021 09:56:36 +0200 (CEST) Received: by po18078vm.idsi0.si.c-s.fr (Postfix, from userid 0) id D51B86BC7E; Tue, 24 Aug 2021 07:56:35 +0000 (UTC) Message-Id: From: Christophe Leroy Subject: [PATCH v2] powerpc: Avoid link stack corruption in misc asm functions To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Tue, 24 Aug 2021 07:56:35 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org bl;mflr is used at several places to get code position. Use bcl 20,31,+4 instead of bl in order to preserve link stack. See commit c974809a26a1 ("powerpc/vdso: Avoid link stack corruption in __get_datapage()") for details. Signed-off-by: Christophe Leroy --- v2: Use $+4 instead of label ; squashed several commits together --- arch/powerpc/kernel/misc.S | 2 +- arch/powerpc/kernel/misc_32.S | 2 +- arch/powerpc/kernel/misc_64.S | 2 +- arch/powerpc/kernel/reloc_32.S | 2 +- arch/powerpc/kexec/relocate_32.S | 12 ++++++------ 5 files changed, 10 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S index 5be96feccb55..fb7de3543c03 100644 --- a/arch/powerpc/kernel/misc.S +++ b/arch/powerpc/kernel/misc.S @@ -29,7 +29,7 @@ _GLOBAL(reloc_offset) li r3, 0 _GLOBAL(add_reloc_offset) mflr r0 - bl 1f + bcl 20,31,$+4 1: mflr r5 PPC_LL r4,(2f-1b)(r5) subf r5,r4,r5 diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index d8645efff902..e5127b19fec2 100644 --- a/arch/powerpc/kernel/misc_32.S +++ b/arch/powerpc/kernel/misc_32.S @@ -67,7 +67,7 @@ _GLOBAL(reloc_got2) srwi. r8,r8,2 beqlr mtctr r8 - bl 1f + bcl 20,31,$+4 1: mflr r0 lis r4,1b@ha addi r4,r4,1b@l diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S index 4b761a18a74d..d38a019b38e1 100644 --- a/arch/powerpc/kernel/misc_64.S +++ b/arch/powerpc/kernel/misc_64.S @@ -255,7 +255,7 @@ _GLOBAL(scom970_write) * Physical (hardware) cpu id should be in r3. */ _GLOBAL(kexec_wait) - bl 1f + bcl 20,31,$+4 1: mflr r5 addi r5,r5,kexec_flag-1b diff --git a/arch/powerpc/kernel/reloc_32.S b/arch/powerpc/kernel/reloc_32.S index 10e96f3e22fe..0508c14b4c28 100644 --- a/arch/powerpc/kernel/reloc_32.S +++ b/arch/powerpc/kernel/reloc_32.S @@ -30,7 +30,7 @@ R_PPC_RELATIVE = 22 _GLOBAL(relocate) mflr r0 /* Save our LR */ - bl 0f /* Find our current runtime address */ + bcl 20,31,$+4 /* Find our current runtime address */ 0: mflr r12 /* Make it accessible */ mtlr r0 diff --git a/arch/powerpc/kexec/relocate_32.S b/arch/powerpc/kexec/relocate_32.S index 61946c19e07c..cf6e52bdf8d8 100644 --- a/arch/powerpc/kexec/relocate_32.S +++ b/arch/powerpc/kexec/relocate_32.S @@ -93,7 +93,7 @@ wmmucr: * Invalidate all the TLB entries except the current entry * where we are running from */ - bl 0f /* Find our address */ + bcl 20,31,$+4 /* Find our address */ 0: mflr r5 /* Make it accessible */ tlbsx r23,0,r5 /* Find entry we are in */ li r4,0 /* Start at TLB entry 0 */ @@ -158,7 +158,7 @@ write_out: /* Switch to other address space in MSR */ insrwi r9, r7, 1, 26 /* Set MSR[IS] = r7 */ - bl 1f + bcl 20,31,$+4 1: mflr r8 addi r8, r8, (2f-1b) /* Find the target offset */ @@ -202,7 +202,7 @@ next_tlb: li r9,0 insrwi r9, r7, 1, 26 /* Set MSR[IS] = r7 */ - bl 1f + bcl 20,31,$+4 1: mflr r8 and r8, r8, r11 /* Get our offset within page */ addi r8, r8, (2f-1b) @@ -240,7 +240,7 @@ setup_map_47x: sync /* Find the entry we are running from */ - bl 2f + bcl 20,31,$+4 2: mflr r23 tlbsx r23, 0, r23 tlbre r24, r23, 0 /* TLB Word 0 */ @@ -296,7 +296,7 @@ clear_utlb_entry: /* Update the msr to the new TS */ insrwi r5, r7, 1, 26 - bl 1f + bcl 20,31,$+4 1: mflr r6 addi r6, r6, (2f-1b) @@ -355,7 +355,7 @@ write_utlb: /* Defaults to 256M */ lis r10, 0x1000 - bl 1f + bcl 20,31,$+4 1: mflr r4 addi r4, r4, (2f-1b) /* virtual address of 2f */ -- 2.25.0