From: Helge Deller <deller@gmx.de>
To: Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
David Hildenbrand <david@redhat.com>,
Suren Baghdasaryan <surenb@google.com>,
Qi Zheng <zhengqi.arch@bytedance.com>,
Peter Zijlstra <peterz@infradead.org>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Greg Ungerer <gerg@linux-m68k.org>,
Michal Simek <monstr@monstr.eu>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
John David Anglin <dave.anglin@bell.net>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Alexandre Ghiti <alexghiti@rivosinc.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Heiko Carstens <hca@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
"David S. Miller" <davem@davemloft.net>,
Chris Zankel <chris@zankel.net>,
Max Filippov <jcmvbkbc@gmail.com>,
x86@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v2 08/23] parisc: add pte_unmap() to balance get_ptep()
Date: Mon, 19 Jun 2023 05:55:42 +0200 [thread overview]
Message-ID: <2f5a3805-b7a5-1c45-e5a4-e273ea289ba6@gmx.de> (raw)
In-Reply-To: <653369-95ef-acd2-d6ea-e95f5a997493@google.com>
On 6/8/23 21:18, Hugh Dickins wrote:
> To keep balance in future, remember to pte_unmap() after a successful
> get_ptep(). And act as if flush_cache_pages() really needs a map there,
> to read the pfn before "unmapping", to be sure page table is not removed.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
For the parisc parts:
Acked-by: Helge Deller <deller@gmx.de> # parisc
Helge
> ---
> arch/parisc/kernel/cache.c | 26 +++++++++++++++++++++-----
> 1 file changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
> index ca4a302d4365..501160250bb7 100644
> --- a/arch/parisc/kernel/cache.c
> +++ b/arch/parisc/kernel/cache.c
> @@ -426,10 +426,15 @@ void flush_dcache_page(struct page *page)
> offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
> addr = mpnt->vm_start + offset;
> if (parisc_requires_coherency()) {
> + bool needs_flush = false;
> pte_t *ptep;
>
> ptep = get_ptep(mpnt->vm_mm, addr);
> - if (ptep && pte_needs_flush(*ptep))
> + if (ptep) {
> + needs_flush = pte_needs_flush(*ptep);
> + pte_unmap(ptep);
> + }
> + if (needs_flush)
> flush_user_cache_page(mpnt, addr);
> } else {
> /*
> @@ -561,14 +566,20 @@ EXPORT_SYMBOL(flush_kernel_dcache_page_addr);
> static void flush_cache_page_if_present(struct vm_area_struct *vma,
> unsigned long vmaddr, unsigned long pfn)
> {
> - pte_t *ptep = get_ptep(vma->vm_mm, vmaddr);
> + bool needs_flush = false;
> + pte_t *ptep;
>
> /*
> * The pte check is racy and sometimes the flush will trigger
> * a non-access TLB miss. Hopefully, the page has already been
> * flushed.
> */
> - if (ptep && pte_needs_flush(*ptep))
> + ptep = get_ptep(vma->vm_mm, vmaddr);
> + if (ptep) {
> + needs_flush = pte_needs_flush(*ptep);
> + pte_unmap(ptep);
> + }
> + if (needs_flush)
> flush_cache_page(vma, vmaddr, pfn);
> }
>
> @@ -635,17 +646,22 @@ static void flush_cache_pages(struct vm_area_struct *vma, unsigned long start, u
> pte_t *ptep;
>
> for (addr = start; addr < end; addr += PAGE_SIZE) {
> + bool needs_flush = false;
> /*
> * The vma can contain pages that aren't present. Although
> * the pte search is expensive, we need the pte to find the
> * page pfn and to check whether the page should be flushed.
> */
> ptep = get_ptep(vma->vm_mm, addr);
> - if (ptep && pte_needs_flush(*ptep)) {
> + if (ptep) {
> + needs_flush = pte_needs_flush(*ptep);
> + pfn = pte_pfn(*ptep);
> + pte_unmap(ptep);
> + }
> + if (needs_flush) {
> if (parisc_requires_coherency()) {
> flush_user_cache_page(vma, addr);
> } else {
> - pfn = pte_pfn(*ptep);
> if (WARN_ON(!pfn_valid(pfn)))
> return;
> __flush_cache_page(vma, addr, PFN_PHYS(pfn));
next prev parent reply other threads:[~2023-06-19 3:57 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-08 19:07 [PATCH v2 00/23] arch: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-06-08 19:10 ` [PATCH v2 01/23] arm: " Hugh Dickins
2023-06-08 19:11 ` [PATCH v2 02/23] arm64: allow pte_offset_map() " Hugh Dickins
2023-06-08 19:13 ` [PATCH v2 03/23] arm64/hugetlb: pte_alloc_huge() pte_offset_huge() Hugh Dickins
2023-06-08 19:14 ` [PATCH v2 04/23] ia64/hugetlb: " Hugh Dickins
2023-06-08 19:15 ` [PATCH v2 05/23] m68k: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-06-08 19:16 ` [PATCH v2 06/23] microblaze: allow pte_offset_map() " Hugh Dickins
2023-06-08 19:17 ` [PATCH v2 07/23] mips: update_mmu_cache() can replace __update_tlb() Hugh Dickins
2023-06-09 8:08 ` [PATCH v2 07/23 fix] mips: update_mmu_cache() can replace __update_tlb(): fix Hugh Dickins
2023-06-14 23:17 ` [PATCH v2 07/23] mips: update_mmu_cache() can replace __update_tlb() Nathan Chancellor
2023-06-15 0:26 ` Hugh Dickins
2023-06-15 5:43 ` Hugh Dickins
2023-06-15 15:50 ` Nathan Chancellor
2023-06-15 21:22 ` Hugh Dickins
2023-06-15 23:02 ` [PATCH v2 07/23 replacement] mips: add pte_unmap() to balance pte_offset_map() Hugh Dickins
2023-06-17 3:54 ` Yu Zhao
2023-06-18 20:57 ` Yu Zhao
2023-06-15 22:07 ` [PATCH v2 07/23] mips: update_mmu_cache() can replace __update_tlb() Yu Zhao
2023-06-08 19:18 ` [PATCH v2 08/23] parisc: add pte_unmap() to balance get_ptep() Hugh Dickins
2023-06-19 3:55 ` Helge Deller [this message]
2023-06-08 19:20 ` [PATCH v2 09/23] parisc: unmap_uncached_pte() use pte_offset_kernel() Hugh Dickins
2023-06-08 19:21 ` [PATCH v2 10/23] parisc/hugetlb: pte_alloc_huge() pte_offset_huge() Hugh Dickins
2023-06-08 19:22 ` [PATCH v2 11/23] powerpc: kvmppc_unmap_free_pmd() pte_offset_kernel() Hugh Dickins
2023-06-08 19:23 ` [PATCH v2 12/23] powerpc: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-06-08 19:24 ` [PATCH v2 13/23] powerpc/hugetlb: pte_alloc_huge() Hugh Dickins
2023-06-08 19:25 ` [PATCH v2 14/23] riscv/hugetlb: pte_alloc_huge() pte_offset_huge() Hugh Dickins
2023-06-08 19:27 ` [PATCH v2 15/23] s390: allow pte_offset_map_lock() to fail Hugh Dickins
2023-06-13 11:45 ` Claudio Imbrenda
2023-06-08 19:29 ` [PATCH v2 16/23] s390: gmap use pte_unmap_unlock() not spin_unlock() Hugh Dickins
2023-06-08 19:30 ` [PATCH v2 17/23] sh/hugetlb: pte_alloc_huge() pte_offset_huge() Hugh Dickins
2023-06-08 19:31 ` [PATCH v2 18/23] sparc/hugetlb: " Hugh Dickins
2023-06-08 19:32 ` [PATCH v2 19/23] sparc: allow pte_offset_map() to fail Hugh Dickins
2023-06-08 19:33 ` [PATCH v2 20/23] sparc: iounit and iommu use pte_offset_kernel() Hugh Dickins
2023-06-08 19:35 ` [PATCH v2 21/23] x86: Allow get_locked_pte() to fail Hugh Dickins
2023-06-08 19:36 ` [PATCH v2 22/23] x86: sme_populate_pgd() use pte_offset_kernel() Hugh Dickins
2023-06-08 19:37 ` [PATCH v2 23/23] xtensa: add pte_unmap() to balance pte_offset_map() Hugh Dickins
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