From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 24/35] mm/memory_hotplug: add pgprot_t to mhp_params Date: Fri, 10 Apr 2020 14:33:36 -0700 Message-ID: <20200410213336.7dA-akMbT%akpm@linux-foundation.org> References: <20200410143047.bf34a933ce1affdc042c7c80@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:47696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726594AbgDJVdh (ORCPT ); Fri, 10 Apr 2020 17:33:37 -0400 In-Reply-To: <20200410143047.bf34a933ce1affdc042c7c80@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, dan.j.williams@intel.com, dave.hansen@linux.intel.com, david@redhat.com, ebadger@gigaio.com, hch@lst.de, hpa@zytor.com, jgg@ziepe.ca, linux-mm@kvack.org, logang@deltatee.com, luto@kernel.org, mhocko@suse.com, mingo@redhat.com, mm-commits@vger.kernel.org, mpe@ellerman.id.au, paulus@samba.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, will@kernel.org From: Logan Gunthorpe Subject: mm/memory_hotplug: add pgprot_t to mhp_params devm_memremap_pages() is currently used by the PCI P2PDMA code to create struct page mappings for IO memory. At present, these mappings are created with PAGE_KERNEL which implies setting the PAT bits to be WB. However, on x86, an mtrr register will typically override this and force the cache type to be UC-. In the case firmware doesn't set this register it is effectively WB and will typically result in a machine check exception when it's accessed. Other arches are not currently likely to function correctly seeing they don't have any MTRR registers to fall back on. To solve this, provide a way to specify the pgprot value explicitly to arch_add_memory(). Of the arches that support MEMORY_HOTPLUG: x86_64, and arm64 need a simple change to pass the pgprot_t down to their respective functions which set up the page tables. For x86_32, set the page tables explicitly using _set_memory_prot() (seeing they are already mapped). For ia64, s390 and sh, reject anything but PAGE_KERNEL settings -- this should be fine, for now, seeing these architectures don't support ZONE_DEVICE. A check in __add_pages() is also added to ensure the pgprot parameter was set for all arches. Link: http://lkml.kernel.org/r/20200306170846.9333-7-logang@deltatee.com Signed-off-by: Logan Gunthorpe Acked-by: David Hildenbrand Acked-by: Michal Hocko Acked-by: Dan Williams Cc: Andy Lutomirski Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Dave Hansen Cc: Eric Badger Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jason Gunthorpe Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/arm64/mm/mmu.c | 3 ++- arch/ia64/mm/init.c | 3 +++ arch/powerpc/mm/mem.c | 3 ++- arch/s390/mm/init.c | 3 +++ arch/sh/mm/init.c | 3 +++ arch/x86/mm/init_32.c | 12 ++++++++++++ arch/x86/mm/init_64.c | 2 +- include/linux/memory_hotplug.h | 3 +++ mm/memory_hotplug.c | 5 ++++- mm/memremap.c | 6 +++--- 10 files changed, 36 insertions(+), 7 deletions(-) --- a/arch/arm64/mm/mmu.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/arm64/mm/mmu.c @@ -1382,7 +1382,8 @@ int arch_add_memory(int nid, u64 start, flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), - size, PAGE_KERNEL, __pgd_pgtable_alloc, flags); + size, params->pgprot, __pgd_pgtable_alloc, + flags); memblock_clear_nomap(start, size); --- a/arch/ia64/mm/init.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/ia64/mm/init.c @@ -676,6 +676,9 @@ int arch_add_memory(int nid, u64 start, unsigned long nr_pages = size >> PAGE_SHIFT; int ret; + if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot)) + return -EINVAL; + ret = __add_pages(nid, start_pfn, nr_pages, params); if (ret) printk("%s: Problem encountered in __add_pages() as ret=%d\n", --- a/arch/powerpc/mm/mem.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/powerpc/mm/mem.c @@ -132,7 +132,8 @@ int __ref arch_add_memory(int nid, u64 s resize_hpt_for_hotplug(memblock_phys_mem_size()); start = (unsigned long)__va(start); - rc = create_section_mapping(start, start + size, nid, PAGE_KERNEL); + rc = create_section_mapping(start, start + size, nid, + params->pgprot); if (rc) { pr_warn("Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n", start, start + size, rc); --- a/arch/s390/mm/init.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/s390/mm/init.c @@ -277,6 +277,9 @@ int arch_add_memory(int nid, u64 start, if (WARN_ON_ONCE(params->altmap)) return -EINVAL; + if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot)) + return -EINVAL; + rc = vmem_add_mapping(start, size); if (rc) return rc; --- a/arch/sh/mm/init.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/sh/mm/init.c @@ -412,6 +412,9 @@ int arch_add_memory(int nid, u64 start, unsigned long nr_pages = size >> PAGE_SHIFT; int ret; + if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot) + return -EINVAL; + /* We only have ZONE_NORMAL, so this is easy.. */ ret = __add_pages(nid, start_pfn, nr_pages, params); if (unlikely(ret)) --- a/arch/x86/mm/init_32.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/x86/mm/init_32.c @@ -824,6 +824,18 @@ int arch_add_memory(int nid, u64 start, { unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + int ret; + + /* + * The page tables were already mapped at boot so if the caller + * requests a different mapping type then we must change all the + * pages with __set_memory_prot(). + */ + if (params->pgprot.pgprot != PAGE_KERNEL.pgprot) { + ret = __set_memory_prot(start, nr_pages, params->pgprot); + if (ret) + return ret; + } return __add_pages(nid, start_pfn, nr_pages, params); } --- a/arch/x86/mm/init_64.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/arch/x86/mm/init_64.c @@ -867,7 +867,7 @@ int arch_add_memory(int nid, u64 start, unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; - init_memory_mapping(start, start + size, PAGE_KERNEL); + init_memory_mapping(start, start + size, params->pgprot); return add_pages(nid, start_pfn, nr_pages, params); } --- a/include/linux/memory_hotplug.h~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/include/linux/memory_hotplug.h @@ -60,9 +60,12 @@ enum { /* * Extended parameters for memory hotplug: * altmap: alternative allocator for memmap array (optional) + * pgprot: page protection flags to apply to newly created page tables + * (required) */ struct mhp_params { struct vmem_altmap *altmap; + pgprot_t pgprot; }; /* --- a/mm/memory_hotplug.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/mm/memory_hotplug.c @@ -311,6 +311,9 @@ int __ref __add_pages(int nid, unsigned int err; struct vmem_altmap *altmap = params->altmap; + if (WARN_ON_ONCE(!params->pgprot.pgprot)) + return -EINVAL; + err = check_hotplug_memory_addressable(pfn, nr_pages); if (err) return err; @@ -1002,7 +1005,7 @@ static int online_memory_block(struct me */ int __ref add_memory_resource(int nid, struct resource *res) { - struct mhp_params params = {}; + struct mhp_params params = { .pgprot = PAGE_KERNEL }; u64 start, size; bool new_node = false; int ret; --- a/mm/memremap.c~mm-memory_hotplug-add-pgprot_t-to-mhp_params +++ a/mm/memremap.c @@ -189,8 +189,8 @@ void *memremap_pages(struct dev_pagemap * We do not want any optional features only our own memmap */ .altmap = pgmap_altmap(pgmap), + .pgprot = PAGE_KERNEL, }; - pgprot_t pgprot = PAGE_KERNEL; int error, is_ram; bool need_devmap_managed = true; @@ -282,8 +282,8 @@ void *memremap_pages(struct dev_pagemap if (nid < 0) nid = numa_mem_id(); - error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(res->start), 0, - resource_size(res)); + error = track_pfn_remap(NULL, ¶ms.pgprot, PHYS_PFN(res->start), + 0, resource_size(res)); if (error) goto err_pfn_remap; _