From nobody Sat Apr 18 17:26:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 488E2C43334 for ; Tue, 12 Jul 2022 12:30:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233103AbiGLMas (ORCPT ); Tue, 12 Jul 2022 08:30:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233034AbiGLMal (ORCPT ); Tue, 12 Jul 2022 08:30:41 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6351437FB8; Tue, 12 Jul 2022 05:30:40 -0700 (PDT) Received: from localhost.localdomain.localdomain (unknown [10.2.5.46]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxP9Jnac1icVQZAA--.16223S2; Tue, 12 Jul 2022 20:30:38 +0800 (CST) From: Hongchen Zhang To: Thomas Bogendoerfer Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, Hongchen Zhang Subject: [PATCH v2] MIPS: fix pmd_mkinvalid Date: Tue, 12 Jul 2022 20:30:29 +0800 Message-Id: <1657629029-27799-1-git-send-email-zhanghongchen@loongson.cn> X-Mailer: git-send-email 1.8.3.1 X-CM-TRANSID: AQAAf9DxP9Jnac1icVQZAA--.16223S2 X-Coremail-Antispam: 1UD129KBjvJXoWxur43Zry7GF45ZF15tw1UJrb_yoW5Ww4Dpa n7AF9Y9rWYg34IyayYyr92gr15ArsxKFZ0gryDWr1jva43XrZ7Xrn3KwnIyFy8XayvyFy8 WrWSqan8GrWIv3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUka14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVCm-wCF04k2 0xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI 8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41l IxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIx AIcVCF04k26cxKx2IYs7xG6rWUJVWrZr1UMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvE x4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUywZ7UUUUU= X-CM-SenderInfo: x2kd0w5krqwupkhqwqxorr0wxvrqhubq/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" There is a problem now: CPU 0 CPU 1 pmdp_invalidate do_page_fault ... __handle_mm_fault is_swap_pmd =3D=3D true trigger VM_BUG_ON() ? set_pmd_at the reason is when a pmd entry is invalidated by pmd_mkinvalid, pmd_present should return true but now pmd_present return false. Like arm64 does in commit b65399f6111b ("arm64/mm: Change THP helpers to comply with generic MM semantics"). we introduce a _PMD_PRESENT_INVALID_SHIFT bit to check if a pmd is present but invalidated by pmd_mkinvalid. After this commit pmd_present will return the correct value and the VM_BUG_ON will not be triggered. Signed-off-by: Hongchen Zhang --- arch/mips/include/asm/pgtable-64.h | 2 +- arch/mips/include/asm/pgtable-bits.h | 2 ++ arch/mips/include/asm/pgtable.h | 3 +++ 3 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgt= able-64.h index 41921ac..050cf66 100644 --- a/arch/mips/include/asm/pgtable-64.h +++ b/arch/mips/include/asm/pgtable-64.h @@ -265,7 +265,7 @@ static inline int pmd_present(pmd_t pmd) { #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT if (unlikely(pmd_val(pmd) & _PAGE_HUGE)) - return pmd_val(pmd) & _PAGE_PRESENT; + return pmd_val(pmd) & (_PAGE_PRESENT | _PMD_PRESENT_INVALID); #endif =20 return pmd_val(pmd) !=3D (unsigned long) invalid_pte_table; diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/p= gtable-bits.h index 2362842..72cd88a 100644 --- a/arch/mips/include/asm/pgtable-bits.h +++ b/arch/mips/include/asm/pgtable-bits.h @@ -130,6 +130,7 @@ enum pgtable_bits { _PAGE_MODIFIED_SHIFT, #if defined(CONFIG_MIPS_HUGE_TLB_SUPPORT) _PAGE_HUGE_SHIFT, + _PMD_PRESENT_INVALID_SHIFT, #endif #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL) _PAGE_SPECIAL_SHIFT, @@ -157,6 +158,7 @@ enum pgtable_bits { #define _PAGE_MODIFIED (1 << _PAGE_MODIFIED_SHIFT) #if defined(CONFIG_MIPS_HUGE_TLB_SUPPORT) # define _PAGE_HUGE (1 << _PAGE_HUGE_SHIFT) +#define _PMD_PRESENT_INVALID (1 << _PMD_PRESENT_INVALID_SHIFT) #endif #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL) # define _PAGE_SPECIAL (1 << _PAGE_SPECIAL_SHIFT) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtabl= e.h index 374c632..a75f461 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -696,12 +696,15 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t ne= wprot) return pmd; } =20 +#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT static inline pmd_t pmd_mkinvalid(pmd_t pmd) { + pmd_val(pmd) |=3D _PMD_PRESENT_INVALID; pmd_val(pmd) &=3D ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY); =20 return pmd; } +#endif =20 /* * The generic version pmdp_huge_get_and_clear uses a version of pmd_clear= () with a --=20 1.8.3.1