From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leonardo Bras Subject: [PATCH v6 06/11] powerpc/mm/book3s64/hash: Use functions to track lockless pgtbl walks Date: Thu, 6 Feb 2020 00:08:55 -0300 Message-ID: <20200206030900.147032-7-leonardo@linux.ibm.com> References: <20200206030900.147032-1-leonardo@linux.ibm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:64088 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727703AbgBFDMD (ORCPT ); Wed, 5 Feb 2020 22:12:03 -0500 In-Reply-To: <20200206030900.147032-1-leonardo@linux.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Arnd Bergmann , Andrew Morton , "Aneesh Kumar K.V" , Nicholas Piggin , Christophe Leroy , Steven Price , Robin Murphy , Leonardo Bras , Mahesh Salgaonkar , Balbir Singh , Reza Arbab , Thomas Gleixner , Allison Randal , Greg Kroah-Hartman , Mike Rapoport , Michal Suchanek Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Applies the new tracking functions to all hash-related functions that do lockless pagetable walks. hash_page_mm: Adds comment that explain that there is no need to local_int_disable/save given that it is only called from DataAccess interrupt, so interrupts are already disabled. local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk, so there is no need to repeat it here. Variable that saves the irq mask was renamed from flags to irq_mask so it doesn't lose meaning now it's not directly passed to local_irq_* functions. Signed-off-by: Leonardo Bras --- arch/powerpc/mm/book3s64/hash_tlb.c | 6 +++--- arch/powerpc/mm/book3s64/hash_utils.c | 27 +++++++++++++++++---------- 2 files changed, 20 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c index 4a70d8dd39cd..86547c4151f6 100644 --- a/arch/powerpc/mm/book3s64/hash_tlb.c +++ b/arch/powerpc/mm/book3s64/hash_tlb.c @@ -194,7 +194,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, { bool is_thp; int hugepage_shift; - unsigned long flags; + unsigned long irq_mask; start = _ALIGN_DOWN(start, PAGE_SIZE); end = _ALIGN_UP(end, PAGE_SIZE); @@ -209,7 +209,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, * to being hashed). This is not the most performance oriented * way to do things but is fine for our needs here. */ - local_irq_save(flags); + irq_mask = begin_lockless_pgtbl_walk(); arch_enter_lazy_mmu_mode(); for (; start < end; start += PAGE_SIZE) { pte_t *ptep = find_current_mm_pte(mm->pgd, start, &is_thp, @@ -229,7 +229,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, hpte_need_flush(mm, start, ptep, pte, hugepage_shift); } arch_leave_lazy_mmu_mode(); - local_irq_restore(flags); + end_lockless_pgtbl_walk(irq_mask); } void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr) diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 523d4d39d11e..e6d4ab42173b 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -1341,12 +1341,16 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1); #endif /* CONFIG_PPC_64K_PAGES */ - /* Get PTE and page size from page tables */ + /* Get PTE and page size from page tables : + * Called in from DataAccess interrupt (data_access_common: 0x300), + * interrupts are disabled here. + */ + __begin_lockless_pgtbl_walk(false); ptep = find_linux_pte(pgdir, ea, &is_thp, &hugeshift); if (ptep == NULL || !pte_present(*ptep)) { DBG_LOW(" no PTE !\n"); rc = 1; - goto bail; + goto bail_pgtbl_walk; } /* Add _PAGE_PRESENT to the required access perm */ @@ -1359,7 +1363,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, if (!check_pte_access(access, pte_val(*ptep))) { DBG_LOW(" no access !\n"); rc = 1; - goto bail; + goto bail_pgtbl_walk; } if (hugeshift) { @@ -1383,7 +1387,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, if (current->mm == mm) check_paca_psize(ea, mm, psize, user_region); - goto bail; + goto bail_pgtbl_walk; } #ifndef CONFIG_PPC_64K_PAGES @@ -1457,6 +1461,8 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, #endif DBG_LOW(" -> rc=%d\n", rc); +bail_pgtbl_walk: + __end_lockless_pgtbl_walk(0, false); bail: exception_exit(prev_state); return rc; @@ -1545,7 +1551,7 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea, unsigned long vsid; pgd_t *pgdir; pte_t *ptep; - unsigned long flags; + unsigned long irq_mask; int rc, ssize, update_flags = 0; unsigned long access = _PAGE_PRESENT | _PAGE_READ | (is_exec ? _PAGE_EXEC : 0); @@ -1567,11 +1573,12 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea, vsid = get_user_vsid(&mm->context, ea, ssize); if (!vsid) return; + /* * Hash doesn't like irqs. Walking linux page table with irq disabled * saves us from holding multiple locks. */ - local_irq_save(flags); + irq_mask = begin_lockless_pgtbl_walk(); /* * THP pages use update_mmu_cache_pmd. We don't do @@ -1616,7 +1623,7 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea, mm_ctx_user_psize(&mm->context), pte_val(*ptep)); out_exit: - local_irq_restore(flags); + end_lockless_pgtbl_walk(irq_mask); } /* @@ -1679,16 +1686,16 @@ u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address) { pte_t *ptep; u16 pkey = 0; - unsigned long flags; + unsigned long irq_mask; if (!mm || !mm->pgd) return 0; - local_irq_save(flags); + irq_mask = begin_lockless_pgtbl_walk(); ptep = find_linux_pte(mm->pgd, address, NULL, NULL); if (ptep) pkey = pte_to_pkey_bits(pte_val(READ_ONCE(*ptep))); - local_irq_restore(flags); + end_lockless_pgtbl_walk(irq_mask); return pkey; } -- 2.24.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Leonardo Bras Subject: [PATCH v6 06/11] powerpc/mm/book3s64/hash: Use functions to track lockless pgtbl walks Date: Thu, 6 Feb 2020 00:08:55 -0300 Message-ID: <20200206030900.147032-7-leonardo@linux.ibm.com> In-Reply-To: <20200206030900.147032-1-leonardo@linux.ibm.com> References: <20200206030900.147032-1-leonardo@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Arnd Bergmann , Andrew Morton , "Aneesh Kumar K.V" , Nicholas Piggin , Christophe Leroy , Steven Price , Robin Murphy , Leonardo Bras , Mahesh Salgaonkar , Balbir Singh , Reza Arbab , Thomas Gleixner , Allison Randal , Greg Kroah-Hartman , Mike Rapoport , Michal Suchanek Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org List-ID: Message-ID: <20200206030855.GwC5ORwVAbGXZEuw5EEEskAc-8ibhmSVQgUSM1nFX2Q@z> Applies the new tracking functions to all hash-related functions that do lockless pagetable walks. hash_page_mm: Adds comment that explain that there is no need to local_int_disable/save given that it is only called from DataAccess interrupt, so interrupts are already disabled. local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk, so there is no need to repeat it here. Variable that saves the irq mask was renamed from flags to irq_mask so it doesn't lose meaning now it's not directly passed to local_irq_* functions. Signed-off-by: Leonardo Bras --- arch/powerpc/mm/book3s64/hash_tlb.c | 6 +++--- arch/powerpc/mm/book3s64/hash_utils.c | 27 +++++++++++++++++---------- 2 files changed, 20 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c index 4a70d8dd39cd..86547c4151f6 100644 --- a/arch/powerpc/mm/book3s64/hash_tlb.c +++ b/arch/powerpc/mm/book3s64/hash_tlb.c @@ -194,7 +194,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, { bool is_thp; int hugepage_shift; - unsigned long flags; + unsigned long irq_mask; start = _ALIGN_DOWN(start, PAGE_SIZE); end = _ALIGN_UP(end, PAGE_SIZE); @@ -209,7 +209,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, * to being hashed). This is not the most performance oriented * way to do things but is fine for our needs here. */ - local_irq_save(flags); + irq_mask = begin_lockless_pgtbl_walk(); arch_enter_lazy_mmu_mode(); for (; start < end; start += PAGE_SIZE) { pte_t *ptep = find_current_mm_pte(mm->pgd, start, &is_thp, @@ -229,7 +229,7 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, hpte_need_flush(mm, start, ptep, pte, hugepage_shift); } arch_leave_lazy_mmu_mode(); - local_irq_restore(flags); + end_lockless_pgtbl_walk(irq_mask); } void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr) diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index 523d4d39d11e..e6d4ab42173b 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -1341,12 +1341,16 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, ea &= ~((1ul << mmu_psize_defs[psize].shift) - 1); #endif /* CONFIG_PPC_64K_PAGES */ - /* Get PTE and page size from page tables */ + /* Get PTE and page size from page tables : + * Called in from DataAccess interrupt (data_access_common: 0x300), + * interrupts are disabled here. + */ + __begin_lockless_pgtbl_walk(false); ptep = find_linux_pte(pgdir, ea, &is_thp, &hugeshift); if (ptep == NULL || !pte_present(*ptep)) { DBG_LOW(" no PTE !\n"); rc = 1; - goto bail; + goto bail_pgtbl_walk; } /* Add _PAGE_PRESENT to the required access perm */ @@ -1359,7 +1363,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, if (!check_pte_access(access, pte_val(*ptep))) { DBG_LOW(" no access !\n"); rc = 1; - goto bail; + goto bail_pgtbl_walk; } if (hugeshift) { @@ -1383,7 +1387,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, if (current->mm == mm) check_paca_psize(ea, mm, psize, user_region); - goto bail; + goto bail_pgtbl_walk; } #ifndef CONFIG_PPC_64K_PAGES @@ -1457,6 +1461,8 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, #endif DBG_LOW(" -> rc=%d\n", rc); +bail_pgtbl_walk: + __end_lockless_pgtbl_walk(0, false); bail: exception_exit(prev_state); return rc; @@ -1545,7 +1551,7 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea, unsigned long vsid; pgd_t *pgdir; pte_t *ptep; - unsigned long flags; + unsigned long irq_mask; int rc, ssize, update_flags = 0; unsigned long access = _PAGE_PRESENT | _PAGE_READ | (is_exec ? _PAGE_EXEC : 0); @@ -1567,11 +1573,12 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea, vsid = get_user_vsid(&mm->context, ea, ssize); if (!vsid) return; + /* * Hash doesn't like irqs. Walking linux page table with irq disabled * saves us from holding multiple locks. */ - local_irq_save(flags); + irq_mask = begin_lockless_pgtbl_walk(); /* * THP pages use update_mmu_cache_pmd. We don't do @@ -1616,7 +1623,7 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea, mm_ctx_user_psize(&mm->context), pte_val(*ptep)); out_exit: - local_irq_restore(flags); + end_lockless_pgtbl_walk(irq_mask); } /* @@ -1679,16 +1686,16 @@ u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address) { pte_t *ptep; u16 pkey = 0; - unsigned long flags; + unsigned long irq_mask; if (!mm || !mm->pgd) return 0; - local_irq_save(flags); + irq_mask = begin_lockless_pgtbl_walk(); ptep = find_linux_pte(mm->pgd, address, NULL, NULL); if (ptep) pkey = pte_to_pkey_bits(pte_val(READ_ONCE(*ptep))); - local_irq_restore(flags); + end_lockless_pgtbl_walk(irq_mask); return pkey; } -- 2.24.1