blackbird-op-linux/arch/s390/mm, branch master

s390/mm: fix dynamic pagetable upgrade for hugetlbfs

2020-01-30T12:07:54+00:00

Commit ee71d16d22bb ("s390/mm: make TASK_SIZE independent from the number of page table levels") changed the logic of TASK_SIZE and also removed the arch_mmap_check() implementation for s390. This combination has a subtle effect on how get_unmapped_area() for hugetlbfs pages works. It is now possible that a user process establishes a hugetlbfs mapping at an address above 4 TB, without triggering a dynamic pagetable upgrade from 3 to 4 levels. This is because hugetlbfs mappings will not use mm->get_unmapped_area, but rather file->f_op->get_unmapped_area, which currently is the generic implementation of hugetlb_get_unmapped_area() that does not know about s390 dynamic pagetable upgrades, but with the new definition of TASK_SIZE, it will now allow mappings above 4 TB. Subsequent access to such a mapped address above 4 TB will result in a page fault loop, because the CPU cannot translate such a large address with 3 pagetable levels. The fault handler will try to map in a hugepage at the address, but due to the folded pagetable logic it will end up with creating entries in the 3 level pagetable, possibly overwriting existing mappings, and then it all repeats when the access is retried. Apart from the page fault loop, this can have various nasty effects, e.g. kernel panic from one of the BUG_ON() checks in memory management code, or even data loss if an existing mapping gets overwritten. Fix this by implementing HAVE_ARCH_HUGETLB_UNMAPPED_AREA support for s390, providing an s390 version for hugetlb_get_unmapped_area() with pagetable upgrade support similar to arch_get_unmapped_area(), which will then be used instead of the generic version. Fixes: ee71d16d22bb ("s390/mm: make TASK_SIZE independent from the number of page table levels") Cc: # 4.12+ Signed-off-by: Gerald Schaefer Signed-off-by: Vasily Gorbik

mm/memory_hotplug: shrink zones when offlining memory

2020-01-04T21:55:08+00:00

We currently try to shrink a single zone when removing memory. We use the zone of the first page of the memory we are removing. If that memmap was never initialized (e.g., memory was never onlined), we will read garbage and can trigger kernel BUGs (due to a stale pointer): BUG: unable to handle page fault for address: 000000000000353d #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP PTI CPU: 1 PID: 7 Comm: kworker/u8:0 Not tainted 5.3.0-rc5-next-20190820+ #317 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4 Workqueue: kacpi_hotplug acpi_hotplug_work_fn RIP: 0010:clear_zone_contiguous+0x5/0x10 Code: 48 89 c6 48 89 c3 e8 2a fe ff ff 48 85 c0 75 cf 5b 5d c3 c6 85 fd 05 00 00 01 5b 5d c3 0f 1f 840 RSP: 0018:ffffad2400043c98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000200000000 RCX: 0000000000000000 RDX: 0000000000200000 RSI: 0000000000140000 RDI: 0000000000002f40 RBP: 0000000140000000 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000 R13: 0000000000140000 R14: 0000000000002f40 R15: ffff9e3e7aff3680 FS: 0000000000000000(0000) GS:ffff9e3e7bb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000353d CR3: 0000000058610000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_pages+0x4b/0x640 arch_remove_memory+0x63/0x8d try_remove_memory+0xdb/0x130 __remove_memory+0xa/0x11 acpi_memory_device_remove+0x70/0x100 acpi_bus_trim+0x55/0x90 acpi_device_hotplug+0x227/0x3a0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x221/0x550 worker_thread+0x50/0x3b0 kthread+0x105/0x140 ret_from_fork+0x3a/0x50 Modules linked in: CR2: 000000000000353d Instead, shrink the zones when offlining memory or when onlining failed. Introduce and use remove_pfn_range_from_zone(() for that. We now properly shrink the zones, even if we have DIMMs whereby - Some memory blocks fall into no zone (never onlined) - Some memory blocks fall into multiple zones (offlined+re-onlined) - Multiple memory blocks that fall into different zones Drop the zone parameter (with a potential dubious value) from __remove_pages() and __remove_section(). Link: http://lkml.kernel.org/r/20191006085646.5768-6-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Aneesh Kumar K.V" Cc: Pavel Tatashin Cc: Greg Kroah-Hartman Cc: Dan Williams Cc: Logan Gunthorpe Cc: [5.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

s390/kasan: add KASAN_VMALLOC support

2019-12-11T18:56:59+00:00

Add KASAN_VMALLOC support which now enables vmalloc memory area access checks as well as enables usage of VMAP_STACK under kasan. KASAN_VMALLOC changes the way vmalloc and modules areas shadow memory is handled. With this new approach only top level page tables are pre-populated and lower levels are filled dynamically upon memory allocation. Acked-by: Ilya Leoshkevich Signed-off-by: Vasily Gorbik

s390: disable preemption when switching to nodat stack with CALL_ON_STACK

2019-11-30T09:52:45+00:00

Make sure preemption is disabled when temporary switching to nodat stack with CALL_ON_STACK helper, because nodat stack is per cpu. Reviewed-by: Heiko Carstens Signed-off-by: Vasily Gorbik

Merge tag 's390-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2019-11-26T01:23:53+00:00

Pull s390 updates from Vasily Gorbik: - Adjust PMU device drivers registration to avoid WARN_ON and few other perf improvements. - Enhance tracing in vfio-ccw. - Few stack unwinder fixes and improvements, convert get_wchan custom stack unwinding to generic api usage. - Fixes for mm helpers issues uncovered with tests validating architecture page table helpers. - Fix noexec bit handling when hardware doesn't support it. - Fix memleak and unsigned value compared with zero bugs in crypto code. Minor code simplification. - Fix crash during kdump with kasan enabled kernel. - Switch bug and alternatives from asm to asm_inline to improve inlining decisions. - Use 'depends on cc-option' for MARCH and TUNE options in Kconfig, add z13s and z14 ZR1 to TUNE descriptions. - Minor head64.S simplification. - Fix physical to logical CPU map for SMT. - Several cleanups in qdio code. - Other minor cleanups and fixes all over the code. * tag 's390-5.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (41 commits) s390/cpumf: Adjust registration of s390 PMU device drivers s390/smp: fix physical to logical CPU map for SMT s390/early: move access registers setup in C code s390/head64: remove unnecessary vdso_per_cpu_data setup s390/early: move control registers setup in C code s390/kasan: support memcpy_real with TRACE_IRQFLAGS s390/crypto: Fix unsigned variable compared with zero s390/pkey: use memdup_user() to simplify code s390/pkey: fix memory leak within _copy_apqns_from_user() s390/disassembler: don't hide instruction addresses s390/cpum_sf: Assign error value to err variable s390/cpum_sf: Replace function name in debug statements s390/cpum_sf: Use consistant debug print format for sampling s390/unwind: drop unnecessary code around calling ftrace_graph_ret_addr() s390: add error handling to perf_callchain_kernel s390: always inline current_stack_pointer() s390/mm: add mm_pxd_folded() checks to pxd_free() s390/mm: properly clear _PAGE_NOEXEC bit when it is not supported s390/mm: simplify page table helpers for large entries s390/mm: make pmd/pud_bad() report large entries as bad ...

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2019-11-25T23:39:19+00:00

Pull arm64 updates from Catalin Marinas: "Apart from the arm64-specific bits (core arch and perf, new arm64 selftests), it touches the generic cow_user_page() (reviewed by Kirill) together with a macro for x86 to preserve the existing behaviour on this architecture. Summary: - On ARMv8 CPUs without hardware updates of the access flag, avoid failing cow_user_page() on PFN mappings if the pte is old. The patches introduce an arch_faults_on_old_pte() macro, defined as false on x86. When true, cow_user_page() makes the pte young before attempting __copy_from_user_inatomic(). - Covert the synchronous exception handling paths in arch/arm64/kernel/entry.S to C. - FTRACE_WITH_REGS support for arm64. - ZONE_DMA re-introduced on arm64 to support Raspberry Pi 4 - Several kselftest cases specific to arm64, together with a MAINTAINERS update for these files (moved to the ARM64 PORT entry). - Workaround for a Neoverse-N1 erratum where the CPU may fetch stale instructions under certain conditions. - Workaround for Cortex-A57 and A72 errata where the CPU may speculatively execute an AT instruction and associate a VMID with the wrong guest page tables (corrupting the TLB). - Perf updates for arm64: additional PMU topologies on HiSilicon platforms, support for CCN-512 interconnect, AXI ID filtering in the IMX8 DDR PMU, support for the CCPI2 uncore PMU in ThunderX2. - GICv3 optimisation to avoid a heavy barrier when accessing the ICC_PMR_EL1 register. - ELF HWCAP documentation updates and clean-up. - SMC calling convention conduit code clean-up. - KASLR diagnostics printed during boot - NVIDIA Carmel CPU added to the KPTI whitelist - Some arm64 mm clean-ups: use generic free_initrd_mem(), remove stale macro, simplify calculation in __create_pgd_mapping(), typos. - Kconfig clean-ups: CMDLINE_FORCE to depend on CMDLINE, choice for endinanness to help with allmodconfig" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (93 commits) arm64: Kconfig: add a choice for endianness kselftest: arm64: fix spelling mistake "contiguos" -> "contiguous" arm64: Kconfig: make CMDLINE_FORCE depend on CMDLINE MAINTAINERS: Add arm64 selftests to the ARM64 PORT entry arm64: kaslr: Check command line before looking for a seed arm64: kaslr: Announce KASLR status on boot kselftest: arm64: fake_sigreturn_misaligned_sp kselftest: arm64: fake_sigreturn_bad_size kselftest: arm64: fake_sigreturn_duplicated_fpsimd kselftest: arm64: fake_sigreturn_missing_fpsimd kselftest: arm64: fake_sigreturn_bad_size_for_magic0 kselftest: arm64: fake_sigreturn_bad_magic kselftest: arm64: add helper get_current_context kselftest: arm64: extend test_init functionalities kselftest: arm64: mangle_pstate_invalid_mode_el[123][ht] kselftest: arm64: mangle_pstate_invalid_daif_bits kselftest: arm64: mangle_pstate_invalid_compat_toggle and common utils kselftest: arm64: extend toplevel skeleton Makefile drivers/perf: hisi: update the sccl_id/ccl_id for certain HiSilicon platform arm64: mm: reserve CMA and crashkernel in ZONE_DMA32 ...

s390/kasan: support memcpy_real with TRACE_IRQFLAGS

2019-11-20T11:58:12+00:00

Currently if the kernel is built with CONFIG_TRACE_IRQFLAGS and KASAN and used as crash kernel it crashes itself due to trace_hardirqs_off/trace_hardirqs_on being called with DAT off. This happens because trace_hardirqs_off/trace_hardirqs_on are instrumented and kasan code tries to perform access to shadow memory to validate memory accesses. Kasan shadow memory is populated with vmemmap, so all accesses require DAT on. memcpy_real could be called with DAT on or off (with kasan enabled DAT is set even before early code is executed). Make sure that trace_hardirqs_off/trace_hardirqs_on are called with DAT on and only actual __memcpy_real is called with DAT off. Also annotate __memcpy_real and _memcpy_real with __no_sanitize_address to avoid further problems due to switching DAT off. Reviewed-by: Philipp Rudo Signed-off-by: Vasily Gorbik

dma/direct: turn ARCH_ZONE_DMA_BITS into a variable

2019-11-01T09:41:18+00:00

Some architectures, notably ARM, are interested in tweaking this depending on their runtime DMA addressing limitations. Acked-by: Christoph Hellwig Signed-off-by: Nicolas Saenz Julienne Signed-off-by: Catalin Marinas

s390/cmm: fix information leak in cmm_timeout_handler()

2019-10-31T16:26:48+00:00

The problem is that we were putting the NUL terminator too far: buf[sizeof(buf) - 1] = '\0'; If the user input isn't NUL terminated and they haven't initialized the whole buffer then it leads to an info leak. The NUL terminator should be: buf[len - 1] = '\0'; Signed-off-by: Yihui Zeng Cc: stable@vger.kernel.org Signed-off-by: Dan Carpenter [heiko.carstens@de.ibm.com: keep semantics of how *lenp and *ppos are handled] Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

mm: treewide: clarify pgtable_page_{ctor,dtor}() naming

2019-09-26T17:10:44+00:00

The naming of pgtable_page_{ctor,dtor}() seems to have confused a few people, and until recently arm64 used these erroneously/pointlessly for other levels of page table. To make it incredibly clear that these only apply to the PTE level, and to align with the naming of pgtable_pmd_page_{ctor,dtor}(), let's rename them to pgtable_pte_page_{ctor,dtor}(). These changes were generated with the following shell script: ---- git grep -lw 'pgtable_page_.tor' | while read FILE; do sed -i '{s/pgtable_page_ctor/pgtable_pte_page_ctor/}' $FILE; sed -i '{s/pgtable_page_dtor/pgtable_pte_page_dtor/}' $FILE; done ---- ... with the documentation re-flowed to remain under 80 columns, and whitespace fixed up in macros to keep backslashes aligned. There should be no functional change as a result of this patch. Link: http://lkml.kernel.org/r/20190722141133.3116-1-mark.rutland@arm.com Signed-off-by: Mark Rutland Reviewed-by: Mike Rapoport Acked-by: Geert Uytterhoeven [m68k] Cc: Anshuman Khandual Cc: Matthew Wilcox Cc: Michal Hocko Cc: Yu Zhao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds