From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42JdZn0ZxFzF13T for ; Mon, 24 Sep 2018 19:05:20 +1000 (AEST) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w8O95HUD065673 for ; Mon, 24 Sep 2018 05:05:18 -0400 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0b-001b2d01.pphosted.com with ESMTP id 2mpu70mfs9-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 24 Sep 2018 05:05:18 -0400 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Sep 2018 03:05:06 -0600 From: "Aneesh Kumar K.V" To: npiggin@gmail.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" Subject: [RFC PATCH 3/5] arch/powerpc/mm: Nest MMU workaround for mprotect/autonuma RW upgrade. Date: Mon, 24 Sep 2018 14:34:16 +0530 In-Reply-To: <20180924090418.31282-1-aneesh.kumar@linux.ibm.com> References: <20180924090418.31282-1-aneesh.kumar@linux.ibm.com> Message-Id: <20180924090418.31282-4-aneesh.kumar@linux.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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") Do the same for mprotect and autonuma upgrades. Hugetlb is handled in the next patch. Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/book3s/64/pgtable.h | 18 +++++++++++ arch/powerpc/mm/pgtable-book3s64.c | 34 ++++++++++++++++++++ 2 files changed, 52 insertions(+) diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 13a688fc8cd0..5b4ac83a5649 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1291,6 +1291,24 @@ static inline const int pud_pfn(pud_t pud) BUILD_BUG(); return 0; } +#define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION +pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, pte_t *); +void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long, + pte_t *, pte_t, pte_t); + +/* + * Returns true for a Read or Write upgrade of pte. + */ +static inline bool is_pte_upgrade(unsigned long old_val, unsigned long new_val) +{ + if ((!(old_val & _PAGE_READ)) && (new_val & _PAGE_READ)) + return true; + + if ((!(old_val & _PAGE_WRITE)) && (new_val & _PAGE_WRITE)) + return true; + + return false; +} #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */ diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c index 01d7c0f7c4f0..243a7cb1bdba 100644 --- a/arch/powerpc/mm/pgtable-book3s64.c +++ b/arch/powerpc/mm/pgtable-book3s64.c @@ -477,3 +477,37 @@ void arch_report_meminfo(struct seq_file *m) atomic_long_read(&direct_pages_count[MMU_PAGE_1G]) << 20); } #endif /* CONFIG_PROC_FS */ + +pte_t 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, 0); + + return __pte(pte_val); + +} +EXPORT_SYMBOL(ptep_modify_prot_start); + +void 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_tlb_page(vma, addr); + + set_pte_at(mm, addr, ptep, pte); +} +EXPORT_SYMBOL(ptep_modify_prot_commit); -- 2.17.1