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Peter Anvin" CC: , , , , , Guohanjun References: <20240207132204.1720444-1-tongtiangen@huawei.com> From: Tong Tiangen In-Reply-To: <20240207132204.1720444-1-tongtiangen@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm600017.china.huawei.com (7.193.23.234) X-Rspamd-Queue-Id: 01231120019 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: e5wesmndm16x7o131eu19nwkb4wpayh1 X-HE-Tag: 1708239962-502084 X-HE-Meta: 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 9ShrkpCc Z9dx2YESnI7fbKRCsaP4N8ql389NeApGrG/iVpUYjRJOiny4RP4VAPhstd3AGGzv/Y6AtFg/VkUY3xJso0fhvzPR4ayOJ6wtG5o0uPFvVTkLfk7tLEAn//+EyltRICwlFua9IwqoB/H9FVMc8sEjvW9WN2V4f2nybRU2gmwn6hhDRtCl873JRPU9ZwbDXeAQtJm/FXJgskbrdLtLIghZ7fKV6Db93kWBFliLdTURZMK/BoYtkStJK1DxS6XNHUvQlTWU9Yj0IcmY9WPsipGcY4MbPRAmT3Y0PT9ljU7cqoto1DCe05BTfRZgM9Bx1JKFiJ1BwT2i9IzCUBWOu8bC3q0y5ck3681B7oNoKNsKr8JpMp9pv1fALISEx+haWWdkogZZH 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: Hi Mark: Kindly ping :) Thanks. Tong. 在 2024/2/7 21:21, Tong Tiangen 写道: > With the increase of memory capacity and density, the probability of memory > error also increases. The increasing size and density of server RAM in data > centers and clouds have shown increased uncorrectable memory errors. > > Currently, more and more scenarios that can tolerate memory errors，such as > CoW[1,2], KSM copy[3], coredump copy[4], khugepaged[5,6], uaccess copy[7], > etc. > > This patchset introduces a new processing framework on ARM64, which enables > ARM64 to support error recovery in the above scenarios, and more scenarios > can be expanded based on this in the future. > > In arm64, memory error handling in do_sea(), which is divided into two cases: > 1. If the user state consumed the memory errors, the solution is to kill > the user process and isolate the error page. > 2. If the kernel state consumed the memory errors, the solution is to > panic. > > For case 2, Undifferentiated panic may not be the optimal choice, as it can > be handled better. In some scenarios, we can avoid panic, such as uaccess, > if the uaccess fails due to memory error, only the user process will be > affected, killing the user process and isolating the user page with > hardware memory errors is a better choice. > > [1] commit d302c2398ba2 ("mm, hwpoison: when copy-on-write hits poison, take page offline") > [2] commit 1cb9dc4b475c ("mm: hwpoison: support recovery from HugePage copy-on-write faults") > [3] commit 6b970599e807 ("mm: hwpoison: support recovery from ksm_might_need_to_copy()") > [4] commit 245f09226893 ("mm: hwpoison: coredump: support recovery from dump_user_range()") > [5] commit 98c76c9f1ef7 ("mm/khugepaged: recover from poisoned anonymous memory") > [6] commit 12904d953364 ("mm/khugepaged: recover from poisoned file-backed memory") > [7] commit 278b917f8cb9 ("x86/mce: Add _ASM_EXTABLE_CPY for copy user access") > > ------------------ > Test result: > > 1. copy_page(), copy_mc_page() basic function test pass, and the disassembly > contents remains the same before and after refactor. > > 2. copy_to/from_user() access kernel NULL pointer raise translation fault > and dump error message then die(), test pass. > > 3. Test following scenarios: copy_from_user(), get_user(), COW. > > Before patched: trigger a hardware memory error then panic. > After patched: trigger a hardware memory error without panic. > > Testing step: > step1. start an user-process. > step2. poison(einj) the user-process's page. > step3: user-process access the poison page in kernel mode, then trigger SEA. > step4: the kernel will not panic, only the user process is killed, the poison > page is isolated. (before patched, the kernel will panic in do_sea()) > > ------------------ > > Since V10: > Accroding Mark's suggestion: > 1. Merge V10's patch2 and patch3 to V11's patch2. > 2. Patch2(V11): use new fixup_type for ld* in copy_to_user(), fix fatal > issues (NULL kernel pointeraccess) been fixup incorrectly. > 3. Patch2(V11): refactoring the logic of do_sea(). > 4. Patch4(V11): Remove duplicate assembly logic and remove do_mte(). > > Besides: > 1. Patch2(V11): remove st* insn's fixup, st* generally not trigger memory error. > 2. Split a part of the logic of patch2(V11) to patch5(V11), for detail, > see patch5(V11)'s commit msg. > 3. Remove patch6(v10) “arm64: introduce copy_mc_to_kernel() implementation”. > During modification, some problems that cannot be solved in a short > period are found. The patch will be released after the problems are > solved. > 4. Add test result in this patch. > 5. Modify patchset title, do not use machine check and remove "-next". > > Since V9: > 1. Rebase to latest kernel version 6.8-rc2. > 2. Add patch 6/6 to support copy_mc_to_kernel(). > > Since V8: > 1. Rebase to latest kernel version and fix topo in some of the patches. > 2. According to the suggestion of Catalin, I attempted to modify the > return value of function copy_mc_[user]_highpage() to bytes not copied. > During the modification process, I found that it would be more > reasonable to return -EFAULT when copy error occurs (referring to the > newly added patch 4). > > For ARM64, the implementation of copy_mc_[user]_highpage() needs to > consider MTE. Considering the scenario where data copying is successful > but the MTE tag copying fails, it is also not reasonable to return > bytes not copied. > 3. Considering the recent addition of machine check safe support for > multiple scenarios, modify commit message for patch 5 (patch 4 for V8). > > Since V7: > Currently, there are patches supporting recover from poison > consumption for the cow scenario[1]. Therefore, Supporting cow > scenario under the arm64 architecture only needs to modify the relevant > code under the arch/. > [1]https://lore.kernel.org/lkml/20221031201029.102123-1-tony.luck@intel.com/ > > Since V6: > Resend patches that are not merged into the mainline in V6. > > Since V5: > 1. Add patch2/3 to add uaccess assembly helpers. > 2. Optimize the implementation logic of arm64_do_kernel_sea() in patch8. > 3. Remove kernel access fixup in patch9. > All suggestion are from Mark. > > Since V4: > 1. According Michael's suggestion, add patch5. > 2. According Mark's suggestiog, do some restructuring to arm64 > extable, then a new adaptation of machine check safe support is made based > on this. > 3. According Mark's suggestion, support machine check safe in do_mte() in > cow scene. > 4. In V4, two patches have been merged into -next, so V5 not send these > two patches. > > Since V3: > 1. According to Robin's suggestion, direct modify user_ldst and > user_ldp in asm-uaccess.h and modify mte.S. > 2. Add new macro USER_MC in asm-uaccess.h, used in copy_from_user.S > and copy_to_user.S. > 3. According to Robin's suggestion, using micro in copy_page_mc.S to > simplify code. > 4. According to KeFeng's suggestion, modify powerpc code in patch1. > 5. According to KeFeng's suggestion, modify mm/extable.c and some code > optimization. > > Since V2: > 1. According to Mark's suggestion, all uaccess can be recovered due to > memory error. > 2. Scenario pagecache reading is also supported as part of uaccess > (copy_to_user()) and duplication code problem is also solved. > Thanks for Robin's suggestion. > 3. According Mark's suggestion, update commit message of patch 2/5. > 4. According Borisllav's suggestion, update commit message of patch 1/5. > > Since V1: > 1.Consistent with PPC/x86, Using CONFIG_ARCH_HAS_COPY_MC instead of > ARM64_UCE_KERNEL_RECOVERY. > 2.Add two new scenes, cow and pagecache reading. > 3.Fix two small bug(the first two patch). > > V1 in here: > https://lore.kernel.org/lkml/20220323033705.3966643-1-tongtiangen@huawei.com/ > > Tong Tiangen (5): > uaccess: add generic fallback version of copy_mc_to_user() > arm64: add support for ARCH_HAS_COPY_MC > mm/hwpoison: return -EFAULT when copy fail in > copy_mc_[user]_highpage() > arm64: support copy_mc_[user]_highpage() > arm64: send SIGBUS to user process for SEA exception > > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/asm-extable.h | 31 ++++++++++++--- > arch/arm64/include/asm/asm-uaccess.h | 4 ++ > arch/arm64/include/asm/extable.h | 1 + > arch/arm64/include/asm/mte.h | 9 +++++ > arch/arm64/include/asm/page.h | 10 +++++ > arch/arm64/lib/Makefile | 2 + > arch/arm64/lib/copy_mc_page.S | 37 ++++++++++++++++++ > arch/arm64/lib/copy_page.S | 50 +++---------------------- > arch/arm64/lib/copy_page_template.S | 56 ++++++++++++++++++++++++++++ > arch/arm64/lib/copy_to_user.S | 10 ++--- > arch/arm64/lib/mte.S | 29 ++++++++++++++ > arch/arm64/mm/copypage.c | 45 ++++++++++++++++++++++ > arch/arm64/mm/extable.c | 19 ++++++++++ > arch/arm64/mm/fault.c | 39 ++++++++++++++----- > arch/powerpc/include/asm/uaccess.h | 1 + > arch/x86/include/asm/uaccess.h | 1 + > include/linux/highmem.h | 16 ++++++-- > include/linux/uaccess.h | 9 +++++ > mm/khugepaged.c | 4 +- > 20 files changed, 304 insertions(+), 70 deletions(-) > create mode 100644 arch/arm64/lib/copy_mc_page.S > create mode 100644 arch/arm64/lib/copy_page_template.S >