From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot1-f71.google.com (mail-ot1-f71.google.com [209.85.210.71]) by kanga.kvack.org (Postfix) with ESMTP id C1C716B0266 for ; Wed, 10 Oct 2018 23:53:38 -0400 (EDT) Received: by mail-ot1-f71.google.com with SMTP id f95so5343183otb.19 for ; Wed, 10 Oct 2018 20:53:38 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id s3si5177643oth.284.2018.10.10.20.53.37 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Oct 2018 20:53:37 -0700 (PDT) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w9B3mweo011721 for ; Wed, 10 Oct 2018 23:53:37 -0400 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0a-001b2d01.pphosted.com with ESMTP id 2n1xxmg465-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 10 Oct 2018 23:53:36 -0400 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 10 Oct 2018 21:53:36 -0600 From: "Aneesh Kumar K.V" Subject: [PATCH 5/5] arch/powerpc/mm/hugetlb: NestMMU workaround for hugetlb mprotect RW upgrade Date: Thu, 11 Oct 2018 09:22:47 +0530 In-Reply-To: <20181011035247.30687-1-aneesh.kumar@linux.ibm.com> References: <20181011035247.30687-1-aneesh.kumar@linux.ibm.com> Message-Id: <20181011035247.30687-6-aneesh.kumar@linux.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, mpe@ellerman.id.au, benh@kernel.crashing.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" NestMMU requires us to mark the pte invalid and flush the tlb when we do a RW upgrade of pte. We fixed a variant of this in the fault path in commit Fixes: bd5050e38aec ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang") Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/book3s/64/hugetlb.h | 8 +++++ arch/powerpc/include/asm/hugetlb.h | 2 +- arch/powerpc/mm/hugetlbpage.c | 35 ++++++++++++++++++++ 3 files changed, 44 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h index 5b0177733994..a12bde29a5f0 100644 --- a/arch/powerpc/include/asm/book3s/64/hugetlb.h +++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h @@ -42,4 +42,12 @@ static inline bool gigantic_page_supported(void) /* hugepd entry valid bit */ #define HUGEPD_VAL_BITS (0x8000000000000000UL) +#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start +extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep); + +#define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit +extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t new_pte); #endif diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h index 2d00cc530083..60c1d37e446a 100644 --- a/arch/powerpc/include/asm/hugetlb.h +++ b/arch/powerpc/include/asm/hugetlb.h @@ -4,7 +4,6 @@ #ifdef CONFIG_HUGETLB_PAGE #include -#include extern struct kmem_cache *hugepte_cache; @@ -176,6 +175,7 @@ static inline void arch_clear_hugepage_flags(struct page *page) { } +#include #else /* ! CONFIG_HUGETLB_PAGE */ static inline void flush_hugetlb_page(struct vm_area_struct *vma, unsigned long vmaddr) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index a7226ed9cae6..8b098bedaff5 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -913,3 +913,38 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, return 1; } + +#ifdef CONFIG_PPC_BOOK3S_64 +pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ + unsigned long pte_val; + /* + * Clear the _PAGE_PRESENT so that no hardware parallel update is + * possible. Also keep the pte_present true so that we don't take + * wrong fault. + */ + pte_val = pte_update(vma->vm_mm, addr, ptep, + _PAGE_PRESENT, _PAGE_INVALID, 1); + + return __pte(pte_val); +} +EXPORT_SYMBOL(huge_ptep_modify_prot_start); + +void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep, pte_t old_pte, pte_t pte) +{ + struct mm_struct *mm = vma->vm_mm; + + /* + * To avoid NMMU hang while relaxing access we need to flush the tlb before + * we set the new value. + */ + if (is_pte_upgrade(pte_val(old_pte), pte_val(pte)) && + (atomic_read(&mm->context.copros) > 0)) + flush_hugetlb_page(vma, addr); + + set_huge_pte_at(vma->vm_mm, addr, ptep, pte); +} +EXPORT_SYMBOL(huge_ptep_modify_prot_commit); +#endif -- 2.17.1