kernel.git/arch/powerpc/mm, branch linux-6.5.y

powerpc/mm: Fix boot crash with FLATMEM

2023-11-08T13:09:03Z

[ Upstream commit daa9ada2093ed23d52b4c1fe6e13cf78f55cc85f ] Erhard reported that his G5 was crashing with v6.6-rc kernels: mpic: Setting up HT PICs workarounds for U3/U4 BUG: Unable to handle kernel data access at 0xfeffbb62ffec65fe Faulting instruction address: 0xc00000000005dc40 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G T 6.6.0-rc3-PMacGS #1 Hardware name: PowerMac11,2 PPC970MP 0x440101 PowerMac NIP: c00000000005dc40 LR: c000000000066660 CTR: c000000000007730 REGS: c0000000022bf510 TRAP: 0380 Tainted: G T (6.6.0-rc3-PMacGS) MSR: 9000000000001032 CR: 44004242 XER: 00000000 IRQMASK: 3 GPR00: 0000000000000000 c0000000022bf7b0 c0000000010c0b00 00000000000001ac GPR04: 0000000003c80000 0000000000000300 c0000000f20001ae 0000000000000300 GPR08: 0000000000000006 feffbb62ffec65ff 0000000000000001 0000000000000000 GPR12: 9000000000001032 c000000002362000 c000000000f76b80 000000000349ecd8 GPR16: 0000000002367ba8 0000000002367f08 0000000000000006 0000000000000000 GPR20: 00000000000001ac c000000000f6f920 c0000000022cd985 000000000000000c GPR24: 0000000000000300 00000003b0a3691d c0003e008030000e 0000000000000000 GPR28: c00000000000000c c0000000f20001ee feffbb62ffec65fe 00000000000001ac NIP hash_page_do_lazy_icache+0x50/0x100 LR __hash_page_4K+0x420/0x590 Call Trace: hash_page_mm+0x364/0x6f0 do_hash_fault+0x114/0x2b0 data_access_common_virt+0x198/0x1f0 --- interrupt: 300 at mpic_init+0x4bc/0x10c4 NIP: c000000002020a5c LR: c000000002020a04 CTR: 0000000000000000 REGS: c0000000022bf9f0 TRAP: 0300 Tainted: G T (6.6.0-rc3-PMacGS) MSR: 9000000000001032 CR: 24004248 XER: 00000000 DAR: c0003e008030000e DSISR: 40000000 IRQMASK: 1 ... NIP mpic_init+0x4bc/0x10c4 LR mpic_init+0x464/0x10c4 --- interrupt: 300 pmac_setup_one_mpic+0x258/0x2dc pmac_pic_init+0x28c/0x3d8 init_IRQ+0x90/0x140 start_kernel+0x57c/0x78c start_here_common+0x1c/0x20 A bisect pointed to the breakage beginning with commit 9fee28baa601 ("powerpc: implement the new page table range API"). Analysis of the oops pointed to a struct page with a corrupted compound_head being loaded via page_folio() -> _compound_head() in hash_page_do_lazy_icache(). The access by the mpic code is to an MMIO address, so the expectation is that the struct page for that address would be initialised by init_unavailable_range(), as pointed out by Aneesh. Instrumentation showed that was not the case, which eventually lead to the realisation that pfn_valid() was returning false for that address, causing the struct page to not be initialised. Because the system is using FLATMEM, the version of pfn_valid() in memory_model.h is used: static inline int pfn_valid(unsigned long pfn) { ... return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr; } Which relies on max_mapnr being initialised. Early in boot max_mapnr is zero meaning no PFNs are valid. max_mapnr is initialised in mem_init() called via: start_kernel() mm_core_init() # init/main.c:928 mem_init() But that is too late for the usage in init_unavailable_range() called via: start_kernel() setup_arch() # init/main.c:893 paging_init() free_area_init() init_unavailable_range() Although max_mapnr is currently set in mem_init(), the value is actually already available much earlier, as soon as mem_topology_setup() has completed, which is also before paging_init() is called. So move the initialisation there, which causes paging_init() to correctly initialise the struct page and fixes the bug. This bug seems to have been lurking for years, but went unnoticed because the pre-folio code was inspecting the uninitialised page->flags but not dereferencing it. Thanks to Erhard and Aneesh for help debugging. Reported-by: Erhard Furtner Closes: https://lore.kernel.org/all/20230929132750.3cd98452@yea/ Signed-off-by: Michael Ellerman Link: https://msgid.link/20231023112500.1550208-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc: Don't include lppaca.h in paca.h

2023-09-13T07:53:32Z

[ Upstream commit 1aa000667669fa855853decbb1c69e974d8ff716 ] By adding a forward declaration for struct lppaca we can untangle paca.h and lppaca.h. Also move get_lppaca() into lppaca.h for consistency. Add includes of lppaca.h to some files that need it. Signed-off-by: Michael Ellerman Link: https://msgid.link/20230823055317.751786-3-mpe@ellerman.id.au Stable-dep-of: eac030b22ea1 ("powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT") Signed-off-by: Sasha Levin

powerpc/radix: Move some functions into #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

2023-09-13T07:53:31Z

[ Upstream commit 4a9dd8f292efd614f0a18452e6474fe19ae17b47 ] With skiboot_defconfig, Clang reports: CC arch/powerpc/mm/book3s64/radix_tlb.o arch/powerpc/mm/book3s64/radix_tlb.c:419:20: error: unused function '_tlbie_pid_lpid' [-Werror,-Wunused-function] static inline void _tlbie_pid_lpid(unsigned long pid, unsigned long lpid, ^ arch/powerpc/mm/book3s64/radix_tlb.c:663:20: error: unused function '_tlbie_va_range_lpid' [-Werror,-Wunused-function] static inline void _tlbie_va_range_lpid(unsigned long start, unsigned long end, ^ This is because those functions are only called from functions enclosed in a #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE Move below functions inside that #ifdef * __tlbie_pid_lpid(unsigned long pid, * __tlbie_va_lpid(unsigned long va, unsigned long pid, * fixup_tlbie_pid_lpid(unsigned long pid, unsigned long lpid) * _tlbie_pid_lpid(unsigned long pid, unsigned long lpid, * fixup_tlbie_va_range_lpid(unsigned long va, * __tlbie_va_range_lpid(unsigned long start, unsigned long end, * _tlbie_va_range_lpid(unsigned long start, unsigned long end, Fixes: f0c6fbbb9050 ("KVM: PPC: Book3S HV: Add support for H_RPT_INVALIDATE") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202307260802.Mjr99P5O-lkp@intel.com/ Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/3d72efd39f986ee939d068af69fdce28bd600766.1691568093.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin

Merge tag 'mm-hotfixes-stable-2023-08-25-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-25T18:44:43Z

Pull misc fixes from Andrew Morton: "18 hotfixes. 13 are cc:stable and the remainder pertain to post-6.4 issues or aren't considered suitable for a -stable backport" * tag 'mm-hotfixes-stable-2023-08-25-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: shmem: fix smaps BUG sleeping while atomic selftests: cachestat: catch failing fsync test on tmpfs selftests: cachestat: test for cachestat availability maple_tree: disable mas_wr_append() when other readers are possible madvise:madvise_free_pte_range(): don't use mapcount() against large folio for sharing check madvise:madvise_free_huge_pmd(): don't use mapcount() against large folio for sharing check madvise:madvise_cold_or_pageout_pte_range(): don't use mapcount() against large folio for sharing check mm: multi-gen LRU: don't spin during memcg release mm: memory-failure: fix unexpected return value in soft_offline_page() radix tree: remove unused variable mm: add a call to flush_cache_vmap() in vmap_pfn() selftests/mm: FOLL_LONGTERM need to be updated to 0x100 nilfs2: fix general protection fault in nilfs_lookup_dirty_data_buffers() mm/gup: handle cont-PTE hugetlb pages correctly in gup_must_unshare() via GUP-fast selftests: cgroup: fix test_kmem_basic less than error mm: enable page walking API to lock vmas during the walk smaps: use vm_normal_page_pmd() instead of follow_trans_huge_pmd() mm/gup: reintroduce FOLL_NUMA as FOLL_HONOR_NUMA_FAULT

mm: enable page walking API to lock vmas during the walk

2023-08-21T20:07:20Z

walk_page_range() and friends often operate under write-locked mmap_lock. With introduction of vma locks, the vmas have to be locked as well during such walks to prevent concurrent page faults in these areas. Add an additional member to mm_walk_ops to indicate locking requirements for the walk. The change ensures that page walks which prevent concurrent page faults by write-locking mmap_lock, operate correctly after introduction of per-vma locks. With per-vma locks page faults can be handled under vma lock without taking mmap_lock at all, so write locking mmap_lock would not stop them. The change ensures vmas are properly locked during such walks. A sample issue this solves is do_mbind() performing queue_pages_range() to queue pages for migration. Without this change a concurrent page can be faulted into the area and be left out of migration. Link: https://lkml.kernel.org/r/20230804152724.3090321-2-surenb@google.com Signed-off-by: Suren Baghdasaryan Suggested-by: Linus Torvalds Suggested-by: Jann Horn Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Hugh Dickins Cc: Johannes Weiner Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Michel Lespinasse Cc: Peter Xu Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

powerpc/mm/altmap: Fix altmap boundary check

2023-07-28T06:47:19Z

altmap->free includes the entire free space from which altmap blocks can be allocated. So when checking whether the kernel is doing altmap block free, compute the boundary correctly, otherwise memory hotunplug can fail. Fixes: 9ef34630a461 ("powerpc/mm: Fallback to RAM if the altmap is unusable") Signed-off-by: "Aneesh Kumar K.V" Reviewed-by: David Hildenbrand Signed-off-by: Michael Ellerman Link: https://msgid.link/20230724181320.471386-1-aneesh.kumar@linux.ibm.com

powerpc/kasan: Disable KCOV in KASAN code

2023-07-17T12:49:44Z

As per the generic KASAN code in mm/kasan, disable KCOV with KCOV_INSTRUMENT := n in the makefile. This fixes a ppc64 boot hang when KCOV and KASAN are enabled. kasan_early_init() gets called before a PACA is initialised, but the KCOV hook expects a valid PACA. Suggested-by: Christophe Leroy Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://msgid.link/20230710044143.146840-1-bgray@linux.ibm.com

powerpc/64s: Fix native_hpte_remove() to be irq-safe

2023-07-09T23:47:46Z

Lockdep warns that the use of the hpte_lock in native_hpte_remove() is not safe against an IRQ coming in: ================================ WARNING: inconsistent lock state 6.4.0-rc2-g0c54f4d30ecc #1 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. qemu-system-ppc/93865 [HC0[0]:SC0[0]:HE1:SE1] takes: c0000000021f5180 (hpte_lock){+.?.}-{0:0}, at: native_lock_hpte+0x8/0xd0 {IN-SOFTIRQ-W} state was registered at: lock_acquire+0x134/0x3f0 native_lock_hpte+0x44/0xd0 native_hpte_insert+0xd4/0x2a0 __hash_page_64K+0x218/0x4f0 hash_page_mm+0x464/0x840 do_hash_fault+0x11c/0x260 data_access_common_virt+0x210/0x220 __ip_select_ident+0x140/0x150 ... net_rx_action+0x3bc/0x440 __do_softirq+0x180/0x534 ... sys_sendmmsg+0x34/0x50 system_call_exception+0x128/0x320 system_call_common+0x160/0x2e4 ... Possible unsafe locking scenario: CPU0 ---- lock(hpte_lock); lock(hpte_lock); *** DEADLOCK *** ... Call Trace: dump_stack_lvl+0x98/0xe0 (unreliable) print_usage_bug.part.0+0x250/0x278 mark_lock+0xc9c/0xd30 __lock_acquire+0x440/0x1ca0 lock_acquire+0x134/0x3f0 native_lock_hpte+0x44/0xd0 native_hpte_remove+0xb0/0x190 kvmppc_mmu_map_page+0x650/0x698 [kvm_pr] kvmppc_handle_pagefault+0x534/0x6e8 [kvm_pr] kvmppc_handle_exit_pr+0x6d8/0xe90 [kvm_pr] after_sprg3_load+0x80/0x90 [kvm_pr] kvmppc_vcpu_run_pr+0x108/0x270 [kvm_pr] kvmppc_vcpu_run+0x34/0x48 [kvm] kvm_arch_vcpu_ioctl_run+0x340/0x470 [kvm] kvm_vcpu_ioctl+0x338/0x8b8 [kvm] sys_ioctl+0x7c4/0x13e0 system_call_exception+0x128/0x320 system_call_common+0x160/0x2e4 I suspect kvm_pr is the only caller that doesn't already have IRQs disabled, which is why this hasn't been reported previously. Fix it by disabling IRQs in native_hpte_remove(). Fixes: 35159b5717fa ("powerpc/64s: make HPTE lock and native_tlbie_lock irq-safe") Cc: stable@vger.kernel.org # v6.1+ Signed-off-by: Michael Ellerman Link: https://msgid.link/20230517123033.18430-1-mpe@ellerman.id.au

Merge tag 'powerpc-6.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2023-06-30T16:20:08Z

Pull powerpc updates from Michael Ellerman: - Extend KCSAN support to 32-bit and BookE. Add some KCSAN annotations - Make ELFv2 ABI the default for 64-bit big-endian kernel builds, and use the -mprofile-kernel option (kernel specific ftrace ABI) for big endian ELFv2 kernels - Add initial Dynamic Execution Control Register (DEXCR) support, and allow the ROP protection instructions to be used on Power 10 - Various other small features and fixes Thanks to Aditya Gupta, Aneesh Kumar K.V, Benjamin Gray, Brian King, Christophe Leroy, Colin Ian King, Dmitry Torokhov, Gaurav Batra, Jean Delvare, Joel Stanley, Marco Elver, Masahiro Yamada, Nageswara R Sastry, Nathan Chancellor, Naveen N Rao, Nayna Jain, Nicholas Piggin, Paul Gortmaker, Randy Dunlap, Rob Herring, Rohan McLure, Russell Currey, Sachin Sant, Timothy Pearson, Tom Rix, and Uwe Kleine-König. * tag 'powerpc-6.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (76 commits) powerpc: remove checks for binutils older than 2.25 powerpc: Fail build if using recordmcount with binutils v2.37 powerpc/iommu: TCEs are incorrectly manipulated with DLPAR add/remove of memory powerpc/iommu: Only build sPAPR access functions on pSeries powerpc: powernv: Annotate data races in opal events powerpc: Mark writes registering ipi to host cpu through kvm and polling powerpc: Annotate accesses to ipi message flags powerpc: powernv: Fix KCSAN datarace warnings on idle_state contention powerpc: Mark [h]ssr_valid accesses in check_return_regs_valid powerpc: qspinlock: Enforce qnode writes prior to publishing to queue powerpc: qspinlock: Mark accesses to qnode lock checks powerpc/powernv/pci: Remove last IODA1 defines powerpc/powernv/pci: Remove MVE code powerpc/powernv/pci: Remove ioda1 support powerpc: 52xx: Make immr_id DT match tables static powerpc: mpc512x: Remove open coded "ranges" parsing powerpc: fsl_soc: Use of_range_to_resource() for "ranges" parsing powerpc: fsl: Use of_property_read_reg() to parse "reg" powerpc: fsl_rio: Use of_range_to_resource() for "ranges" parsing macintosh: Use of_property_read_reg() to parse "reg" ...

Merge branch 'expand-stack'

2023-06-29T03:35:21Z

This modifies our user mode stack expansion code to always take the mmap_lock for writing before modifying the VM layout. It's actually something we always technically should have done, but because we didn't strictly need it, we were being lazy ("opportunistic" sounds so much better, doesn't it?) about things, and had this hack in place where we would extend the stack vma in-place without doing the proper locking. And it worked fine. We just needed to change vm_start (or, in the case of grow-up stacks, vm_end) and together with some special ad-hoc locking using the anon_vma lock and the mm->page_table_lock, it all was fairly straightforward. That is, it was all fine until Ruihan Li pointed out that now that the vma layout uses the maple tree code, we *really* don't just change vm_start and vm_end any more, and the locking really is broken. Oops. It's not actually all _that_ horrible to fix this once and for all, and do proper locking, but it's a bit painful. We have basically three different cases of stack expansion, and they all work just a bit differently: - the common and obvious case is the page fault handling. It's actually fairly simple and straightforward, except for the fact that we have something like 24 different versions of it, and you end up in a maze of twisty little passages, all alike. - the simplest case is the execve() code that creates a new stack. There are no real locking concerns because it's all in a private new VM that hasn't been exposed to anybody, but lockdep still can end up unhappy if you get it wrong. - and finally, we have GUP and page pinning, which shouldn't really be expanding the stack in the first place, but in addition to execve() we also use it for ptrace(). And debuggers do want to possibly access memory under the stack pointer and thus need to be able to expand the stack as a special case. None of these cases are exactly complicated, but the page fault case in particular is just repeated slightly differently many many times. And ia64 in particular has a fairly complicated situation where you can have both a regular grow-down stack _and_ a special grow-up stack for the register backing store. So to make this slightly more manageable, the bulk of this series is to first create a helper function for the most common page fault case, and convert all the straightforward architectures to it. Thus the new 'lock_mm_and_find_vma()' helper function, which ends up being used by x86, arm, powerpc, mips, riscv, alpha, arc, csky, hexagon, loongarch, nios2, sh, sparc32, and xtensa. So we not only convert more than half the architectures, we now have more shared code and avoid some of those twisty little passages. And largely due to this common helper function, the full diffstat of this series ends up deleting more lines than it adds. That still leaves eight architectures (ia64, m68k, microblaze, openrisc, parisc, s390, sparc64 and um) that end up doing 'expand_stack()' manually because they are doing something slightly different from the normal pattern. Along with the couple of special cases in execve() and GUP. So there's a couple of patches that first create 'locked' helper versions of the stack expansion functions, so that there's a obvious path forward in the conversion. The execve() case is then actually pretty simple, and is a nice cleanup from our old "grow-up stackls are special, because at execve time even they grow down". The #ifdef CONFIG_STACK_GROWSUP in that code just goes away, because it's just more straightforward to write out the stack expansion there manually, instead od having get_user_pages_remote() do it for us in some situations but not others and have to worry about locking rules for GUP. And the final step is then to just convert the remaining odd cases to a new world order where 'expand_stack()' is called with the mmap_lock held for reading, but where it might drop it and upgrade it to a write, only to return with it held for reading (in the success case) or with it completely dropped (in the failure case). In the process, we remove all the stack expansion from GUP (where dropping the lock wouldn't be ok without special rules anyway), and add it in manually to __access_remote_vm() for ptrace(). Thanks to Adrian Glaubitz and Frank Scheiner who tested the ia64 cases. Everything else here felt pretty straightforward, but the ia64 rules for stack expansion are really quite odd and very different from everything else. Also thanks to Vegard Nossum who caught me getting one of those odd conditions entirely the wrong way around. Anyway, I think I want to actually move all the stack expansion code to a whole new file of its own, rather than have it split up between mm/mmap.c and mm/memory.c, but since this will have to be backported to the initial maple tree vma introduction anyway, I tried to keep the patches _fairly_ minimal. Also, while I don't think it's valid to expand the stack from GUP, the final patch in here is a "warn if some crazy GUP user wants to try to expand the stack" patch. That one will be reverted before the final release, but it's left to catch any odd cases during the merge window and release candidates. Reported-by: Ruihan Li * branch 'expand-stack': gup: add warning if some caller would seem to want stack expansion mm: always expand the stack with the mmap write lock held execve: expand new process stack manually ahead of time mm: make find_extend_vma() fail if write lock not held powerpc/mm: convert coprocessor fault to lock_mm_and_find_vma() mm/fault: convert remaining simple cases to lock_mm_and_find_vma() arm/mm: Convert to using lock_mm_and_find_vma() riscv/mm: Convert to using lock_mm_and_find_vma() mips/mm: Convert to using lock_mm_and_find_vma() powerpc/mm: Convert to using lock_mm_and_find_vma() arm64/mm: Convert to using lock_mm_and_find_vma() mm: make the page fault mmap locking killable mm: introduce new 'lock_mm_and_find_vma()' page fault helper