From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9847FC48BEB for ; Thu, 15 Feb 2024 11:18:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 378086B008C; Thu, 15 Feb 2024 06:18:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3278D6B0092; Thu, 15 Feb 2024 06:18:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1C86B8D0001; Thu, 15 Feb 2024 06:18:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 09E906B008C for ; Thu, 15 Feb 2024 06:18:55 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id DF1281A0FF3 for ; Thu, 15 Feb 2024 11:18:54 +0000 (UTC) X-FDA: 81793790988.28.020B426 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf11.hostedemail.com (Postfix) with ESMTP id 58A6D40013 for ; Thu, 15 Feb 2024 11:18:53 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf11.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707995933; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N/0FUBbsdbJLAmWkE33tMShnqQmwFXcW8EggdEuKEZo=; b=iKQcZq+OcHueIqPcXumNfgajRKSOmkfAWU+9g7nOyh87uML3U1hIeOtgQrGMrGEPdzls85 7nJDWJ3Ih1UD0VRa/IlnGcT5A2zmF4laBWnvBNg6diWiMU8ntfw2JXdW6WWwcT881tWraC EYLANy1d6o1qXSyK48Q3Op9qHGrHOC0= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf11.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707995933; a=rsa-sha256; cv=none; b=IzgoAEi+4a46mvtKqZtbqGuv0xQzEBOwbscTDppzplDAgGlRay9MD2wm3bcaCgKzq4BRkp /l/hpuzPs2y2FSLjzJpPydqE3aBeKuNu4Nohoqg6ZEHyWrfCXK9iMNqxS8yhqi5BncaJQR Bw80icXOf+5IeUhJs8u5mBP1WnueFyo= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8815E1480; Thu, 15 Feb 2024 03:19:33 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.68.11]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1AB723F7B4; Thu, 15 Feb 2024 03:18:48 -0800 (PST) Date: Thu, 15 Feb 2024 11:18:46 +0000 From: Mark Rutland To: Ryan Roberts Cc: Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , James Morse , Andrey Ryabinin , Andrew Morton , Matthew Wilcox , David Hildenbrand , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 07/18] arm64/mm: Convert READ_ONCE(*ptep) to ptep_get(ptep) Message-ID: References: <20240215103205.2607016-1-ryan.roberts@arm.com> <20240215103205.2607016-8-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240215103205.2607016-8-ryan.roberts@arm.com> X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 58A6D40013 X-Stat-Signature: mcbfe9rdu3fekryckxigcnctn7fs8s8s X-HE-Tag: 1707995933-395323 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Feb 15, 2024 at 10:31:54AM +0000, Ryan Roberts wrote: > There are a number of places in the arch code that read a pte by using > the READ_ONCE() macro. Refactor these call sites to instead use the > ptep_get() helper, which itself is a READ_ONCE(). Generated code should > be the same. > > This will benefit us when we shortly introduce the transparent contpte > support. In this case, ptep_get() will become more complex so we now > have all the code abstracted through it. > > Tested-by: John Hubbard > Signed-off-by: Ryan Roberts Acked-by: Mark Rutland Mark. > --- > arch/arm64/include/asm/pgtable.h | 12 +++++++++--- > arch/arm64/kernel/efi.c | 2 +- > arch/arm64/mm/fault.c | 4 ++-- > arch/arm64/mm/hugetlbpage.c | 6 +++--- > arch/arm64/mm/kasan_init.c | 2 +- > arch/arm64/mm/mmu.c | 12 ++++++------ > arch/arm64/mm/pageattr.c | 4 ++-- > arch/arm64/mm/trans_pgd.c | 2 +- > 8 files changed, 25 insertions(+), 19 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index b6d3e9e0a946..de034ca40bad 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -275,6 +275,12 @@ static inline void set_pte(pte_t *ptep, pte_t pte) > } > } > > +#define ptep_get ptep_get > +static inline pte_t ptep_get(pte_t *ptep) > +{ > + return READ_ONCE(*ptep); > +} > + > extern void __sync_icache_dcache(pte_t pteval); > bool pgattr_change_is_safe(u64 old, u64 new); > > @@ -302,7 +308,7 @@ static inline void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep, > if (!IS_ENABLED(CONFIG_DEBUG_VM)) > return; > > - old_pte = READ_ONCE(*ptep); > + old_pte = ptep_get(ptep); > > if (!pte_valid(old_pte) || !pte_valid(pte)) > return; > @@ -904,7 +910,7 @@ static inline int __ptep_test_and_clear_young(pte_t *ptep) > { > pte_t old_pte, pte; > > - pte = READ_ONCE(*ptep); > + pte = ptep_get(ptep); > do { > old_pte = pte; > pte = pte_mkold(pte); > @@ -986,7 +992,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres > { > pte_t old_pte, pte; > > - pte = READ_ONCE(*ptep); > + pte = ptep_get(ptep); > do { > old_pte = pte; > pte = pte_wrprotect(pte); > diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c > index 0228001347be..d0e08e93b246 100644 > --- a/arch/arm64/kernel/efi.c > +++ b/arch/arm64/kernel/efi.c > @@ -103,7 +103,7 @@ static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data) > { > struct set_perm_data *spd = data; > const efi_memory_desc_t *md = spd->md; > - pte_t pte = READ_ONCE(*ptep); > + pte_t pte = ptep_get(ptep); > > if (md->attribute & EFI_MEMORY_RO) > pte = set_pte_bit(pte, __pgprot(PTE_RDONLY)); > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 55f6455a8284..a254761fa1bd 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -191,7 +191,7 @@ static void show_pte(unsigned long addr) > if (!ptep) > break; > > - pte = READ_ONCE(*ptep); > + pte = ptep_get(ptep); > pr_cont(", pte=%016llx", pte_val(pte)); > pte_unmap(ptep); > } while(0); > @@ -214,7 +214,7 @@ int ptep_set_access_flags(struct vm_area_struct *vma, > pte_t entry, int dirty) > { > pteval_t old_pteval, pteval; > - pte_t pte = READ_ONCE(*ptep); > + pte_t pte = ptep_get(ptep); > > if (pte_same(pte, entry)) > return 0; > diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c > index 6720ec8d50e7..2892f925ed66 100644 > --- a/arch/arm64/mm/hugetlbpage.c > +++ b/arch/arm64/mm/hugetlbpage.c > @@ -485,7 +485,7 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm, > size_t pgsize; > pte_t pte; > > - if (!pte_cont(READ_ONCE(*ptep))) { > + if (!pte_cont(ptep_get(ptep))) { > ptep_set_wrprotect(mm, addr, ptep); > return; > } > @@ -510,7 +510,7 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, > size_t pgsize; > int ncontig; > > - if (!pte_cont(READ_ONCE(*ptep))) > + if (!pte_cont(ptep_get(ptep))) > return ptep_clear_flush(vma, addr, ptep); > > ncontig = find_num_contig(mm, addr, ptep, &pgsize); > @@ -543,7 +543,7 @@ pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr > * when the permission changes from executable to non-executable > * in cases where cpu is affected with errata #2645198. > */ > - if (pte_user_exec(READ_ONCE(*ptep))) > + if (pte_user_exec(ptep_get(ptep))) > return huge_ptep_clear_flush(vma, addr, ptep); > } > return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep); > diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c > index 4c7ad574b946..c2a9f4f6c7dd 100644 > --- a/arch/arm64/mm/kasan_init.c > +++ b/arch/arm64/mm/kasan_init.c > @@ -113,7 +113,7 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, > memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE); > next = addr + PAGE_SIZE; > set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); > - } while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep))); > + } while (ptep++, addr = next, addr != end && pte_none(ptep_get(ptep))); > } > > static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr, > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 3a27d887f7dd..343629a17042 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -173,7 +173,7 @@ static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, > > ptep = pte_set_fixmap_offset(pmdp, addr); > do { > - pte_t old_pte = READ_ONCE(*ptep); > + pte_t old_pte = ptep_get(ptep); > > set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); > > @@ -182,7 +182,7 @@ static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, > * only allow updates to the permission attributes. > */ > BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), > - READ_ONCE(pte_val(*ptep)))); > + pte_val(ptep_get(ptep)))); > > phys += PAGE_SIZE; > } while (ptep++, addr += PAGE_SIZE, addr != end); > @@ -852,7 +852,7 @@ static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, > > do { > ptep = pte_offset_kernel(pmdp, addr); > - pte = READ_ONCE(*ptep); > + pte = ptep_get(ptep); > if (pte_none(pte)) > continue; > > @@ -985,7 +985,7 @@ static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, > > do { > ptep = pte_offset_kernel(pmdp, addr); > - pte = READ_ONCE(*ptep); > + pte = ptep_get(ptep); > > /* > * This is just a sanity check here which verifies that > @@ -1004,7 +1004,7 @@ static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, > */ > ptep = pte_offset_kernel(pmdp, 0UL); > for (i = 0; i < PTRS_PER_PTE; i++) { > - if (!pte_none(READ_ONCE(ptep[i]))) > + if (!pte_none(ptep_get(&ptep[i]))) > return; > } > > @@ -1473,7 +1473,7 @@ pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte > * when the permission changes from executable to non-executable > * in cases where cpu is affected with errata #2645198. > */ > - if (pte_user_exec(READ_ONCE(*ptep))) > + if (pte_user_exec(ptep_get(ptep))) > return ptep_clear_flush(vma, addr, ptep); > } > return ptep_get_and_clear(vma->vm_mm, addr, ptep); > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index 924843f1f661..73a5e8f82586 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -36,7 +36,7 @@ bool can_set_direct_map(void) > static int change_page_range(pte_t *ptep, unsigned long addr, void *data) > { > struct page_change_data *cdata = data; > - pte_t pte = READ_ONCE(*ptep); > + pte_t pte = ptep_get(ptep); > > pte = clear_pte_bit(pte, cdata->clear_mask); > pte = set_pte_bit(pte, cdata->set_mask); > @@ -245,5 +245,5 @@ bool kernel_page_present(struct page *page) > return true; > > ptep = pte_offset_kernel(pmdp, addr); > - return pte_valid(READ_ONCE(*ptep)); > + return pte_valid(ptep_get(ptep)); > } > diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c > index 7b14df3c6477..f71ab4704cce 100644 > --- a/arch/arm64/mm/trans_pgd.c > +++ b/arch/arm64/mm/trans_pgd.c > @@ -33,7 +33,7 @@ static void *trans_alloc(struct trans_pgd_info *info) > > static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr) > { > - pte_t pte = READ_ONCE(*src_ptep); > + pte_t pte = ptep_get(src_ptep); > > if (pte_valid(pte)) { > /* > -- > 2.25.1 >