From patchwork Fri Oct 29 15:10:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1548071 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4Hgm9046QPz9sRN for ; Sat, 30 Oct 2021 02:11:16 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Hgm903Ktzz3c9T for ; Sat, 30 Oct 2021 02:11:16 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.235.10; helo=pegase2.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=) Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Hgm8r2LG9z2ynQ for ; Sat, 30 Oct 2021 02:11:06 +1100 (AEDT) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4Hgm8h6gC7z9sSg; Fri, 29 Oct 2021 17:11:00 +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 hfJUthNRJBNk; Fri, 29 Oct 2021 17:11:00 +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 4Hgm8h5gC2z9sSX; Fri, 29 Oct 2021 17:11:00 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id AEFFC8B78B; Fri, 29 Oct 2021 17:11:00 +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 n1iVfyxHpdhU; Fri, 29 Oct 2021 17:11:00 +0200 (CEST) Received: from PO20335.IDSI0.si.c-s.fr (unknown [172.25.230.108]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 8ED118B763; Fri, 29 Oct 2021 17:11:00 +0200 (CEST) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.16.1/8.16.1) with ESMTPS id 19TFAlHN416774 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 29 Oct 2021 17:10:47 +0200 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.16.1/8.16.1/Submit) id 19TFAkqB416773; Fri, 29 Oct 2021 17:10:46 +0200 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Subject: [PATCH] powerpc/8xx: Fix Oops with STRICT_KERNEL_RWX without DEBUG_RODATA_TEST Date: Fri, 29 Oct 2021 17:10:45 +0200 Message-Id: <3d5800b0bbcd7b19761b98f50421358667b45331.1635520232.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1635520242; l=2802; s=20211009; h=from:subject:message-id; bh=DrNIRDI3/juGgYncviA0c9l6TlqI+AeVZIuktbLAUzE=; b=cF38R5imtMpK7PTLeHkf4mPoxilN8KwtmZYNIWqZOH5AkjaRWPR/P3ZmXeFotR+uDCVy1+aLRhkv knejNNdLCCR+NF6+5GZRyuKREIVeTAE0+NO0g7Btn65pHmSZmIZG X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Until now, all tests involving CONFIG_STRICT_KERNEL_RWX were done with DEBUG_RODATA_TEST to check the result. But now that CONFIG_STRICT_KERNEL_RWX is selected by default, it came without CONFIG_DEBUG_RODATA_TEST and led to the following Oops [ 6.830908] Freeing unused kernel image (initmem) memory: 352K [ 6.840077] BUG: Unable to handle kernel data access on write at 0xc1285200 [ 6.846836] Faulting instruction address: 0xc0004b6c [ 6.851745] Oops: Kernel access of bad area, sig: 11 [#1] [ 6.857075] BE PAGE_SIZE=16K PREEMPT CMPC885 [ 6.861348] SAF3000 DIE NOTIFICATION [ 6.864830] CPU: 0 PID: 1 Comm: swapper Not tainted 5.15.0-rc5-s3k-dev-02255-g2747d7b7916f #451 [ 6.873429] NIP: c0004b6c LR: c0004b60 CTR: 00000000 [ 6.878419] REGS: c902be60 TRAP: 0300 Not tainted (5.15.0-rc5-s3k-dev-02255-g2747d7b7916f) [ 6.886852] MSR: 00009032 CR: 53000335 XER: 8000ff40 [ 6.893564] DAR: c1285200 DSISR: 82000000 [ 6.893564] GPR00: 0c000000 c902bf20 c20f4000 08000000 00000001 04001f00 c1800000 00000035 [ 6.893564] GPR08: ff0001ff c1280000 00000002 c0004b60 00001000 00000000 c0004b1c 00000000 [ 6.893564] GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 6.893564] GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 c1060000 [ 6.932034] NIP [c0004b6c] kernel_init+0x50/0x138 [ 6.936682] LR [c0004b60] kernel_init+0x44/0x138 [ 6.941245] Call Trace: [ 6.943653] [c902bf20] [c0004b60] kernel_init+0x44/0x138 (unreliable) [ 6.950022] [c902bf30] [c001122c] ret_from_kernel_thread+0x5c/0x64 [ 6.956135] Instruction dump: [ 6.959060] 48ffc521 48045469 4800d8cd 3d20c086 89295fa0 2c090000 41820058 480796c9 [ 6.966890] 4800e48d 3d20c128 39400002 3fe0c106 <91495200> 3bff8000 4806fa1d 481f7d75 [ 6.974902] ---[ end trace 1e397bacba4aa610 ]--- 0xc1285200 corresponds to 'system_state' global var that the kernel is trying to set to SYSTEM_RUNNING. This var is above the RO/RW limit so it shouldn't Oops. It oopses because the dirty bit is missing. Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/head_8xx.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 9bdb95f5694f..2d596881b70e 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -755,7 +755,7 @@ _GLOBAL(mmu_pin_tlb) cmplw r6, r9 bdnzt lt, 2b -4: LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT) +4: LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT) 2: ori r0, r6, MD_EVALID mtspr SPRN_MD_CTR, r5 mtspr SPRN_MD_EPN, r0