kernel.git/arch/s390/kernel, branch linux-6.0.y

s390/crashdump: fix TOD programmable field size

2022-12-02T16:43:09Z

[ Upstream commit f44e07a8afdd713ddc1a8832c39372fe5dd86895 ] The size of the TOD programmable field was incorrectly increased from four to eight bytes with commit 1a2c5840acf9 ("s390/dump: cleanup CPU save area handling"). This leads to an elf notes section NT_S390_TODPREG which has a size of eight instead of four bytes in case of kdump, however even worse is that the contents is incorrect: it is supposed to contain only the contents of the TOD programmable field, but in fact contains a mix of the TOD programmable field (32 bit upper bits) and parts of the CPU timer register (lower 32 bits). Fix this by simply changing the size of the todpreg field within the save area structure. This will implicitly also fix the size of the corresponding elf notes sections. This also gets rid of this compile time warning: in function ‘fortify_memcpy_chk’, inlined from ‘save_area_add_regs’ at arch/s390/kernel/crash_dump.c:99:2: ./include/linux/fortify-string.h:413:25: error: call to ‘__read_overflow2_field’ declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror=attribute-warning] 413 | __read_overflow2_field(q_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Fixes: 1a2c5840acf9 ("s390/dump: cleanup CPU save area handling") Reviewed-by: Christian Borntraeger Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

s390/smp: enforce lowcore protection on CPU restart

2022-09-07T12:04:01Z

As result of commit 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called") the low-address protection bit gets mistakenly unset in control register 0 save area of the absolute zero memory. That area is used when manual PSW restart happened to hit an offline CPU. In this case the low-address protection for that CPU will be dropped. Reviewed-by: Heiko Carstens Fixes: 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called") Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik

s390/boot: fix absolute zero lowcore corruption on boot

2022-09-07T12:04:01Z

Crash dump always starts on CPU0. In case CPU0 is offline the prefix page is not installed and the absolute zero lowcore is used. However, struct lowcore::mcesad is never assigned and stays zero. That leads to __machine_kdump() -> save_vx_regs() call silently stores vector registers to the absolute lowcore at 0x11b0 offset. Fixes: a62bc0739253 ("s390/kdump: add support for vector extension") Reviewed-by: Heiko Carstens Signed-off-by: Alexander Gordeev Signed-off-by: Vasily Gorbik

s390: fix nospec table alignments

2022-08-30T19:57:07Z

Add proper alignment for .nospec_call_table and .nospec_return_table in vmlinux. [hca@linux.ibm.com]: The problem with the missing alignment of the nospec tables exist since a long time, however only since commit e6ed91fd0768 ("s390/alternatives: remove padding generation code") and with CONFIG_RELOCATABLE=n the kernel may also crash at boot time. The above named commit reduced the size of struct alt_instr by one byte, so its new size is 11 bytes. Therefore depending on the number of cpu alternatives the size of the __alt_instructions array maybe odd, which again also causes that the addresses of the nospec tables will be odd. If the address of __nospec_call_start is odd and the kernel is compiled With CONFIG_RELOCATABLE=n the compiler may generate code that loads the address of __nospec_call_start with a 'larl' instruction. This will generate incorrect code since the 'larl' instruction only works with even addresses. In result the members of the nospec tables will be accessed with an off-by-one offset, which subsequently may lead to addressing exceptions within __nospec_revert(). Fixes: f19fbd5ed642 ("s390: introduce execute-trampolines for branches") Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/8719bf1ce4a72ebdeb575200290094e9ce047bcc.1661557333.git.jpoimboe@kernel.org Cc: # 4.16 Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: fix double free of GS and RI CBs on fork() failure

2022-08-25T13:12:32Z

The pointers for guarded storage and runtime instrumentation control blocks are stored in the thread_struct of the associated task. These pointers are initially copied on fork() via arch_dup_task_struct() and then cleared via copy_thread() before fork() returns. If fork() happens to fail after the initial task dup and before copy_thread(), the newly allocated task and associated thread_struct memory are freed via free_task() -> arch_release_task_struct(). This results in a double free of the guarded storage and runtime info structs because the fields in the failed task still refer to memory associated with the source task. This problem can manifest as a BUG_ON() in set_freepointer() (with CONFIG_SLAB_FREELIST_HARDENED enabled) or KASAN splat (if enabled) when running trinity syscall fuzz tests on s390x. To avoid this problem, clear the associated pointer fields in arch_dup_task_struct() immediately after the new task is copied. Note that the RI flag is still cleared in copy_thread() because it resides in thread stack memory and that is where stack info is copied. Signed-off-by: Brian Foster Fixes: 8d9047f8b967c ("s390/runtime instrumentation: simplify task exit handling") Fixes: 7b83c6297d2fc ("s390/guarded storage: simplify task exit handling") Cc: # 4.15 Reviewed-by: Gerald Schaefer Reviewed-by: Heiko Carstens Link: https://lore.kernel.org/r/20220816155407.537372-1-bfoster@redhat.com Signed-off-by: Vasily Gorbik

Merge tag 's390-5.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2022-08-07T00:05:21Z

Pull s390 updates from Alexander Gordeev: - Rework copy_oldmem_page() callback to take an iov_iter. This includes a few prerequisite updates and fixes to the oldmem reading code. - Rework cpufeature implementation to allow for various CPU feature indications, which is not only limited to hardware capabilities, but also allows CPU facilities. - Use the cpufeature rework to autoload Ultravisor module when CPU facility 158 is available. - Add ELF note type for encrypted CPU state of a protected virtual CPU. The zgetdump tool from s390-tools package will decrypt the CPU state using a Customer Communication Key and overwrite respective notes to make the data accessible for crash and other debugging tools. - Use vzalloc() instead of vmalloc() + memset() in ChaCha20 crypto test. - Fix incorrect recovery of kretprobe modified return address in stacktrace. - Switch the NMI handler to use generic irqentry_nmi_enter() and irqentry_nmi_exit() helper functions. - Rework the cryptographic Adjunct Processors (AP) pass-through design to support dynamic changes to the AP matrix of a running guest as well as to implement more of the AP architecture. - Minor boot code cleanups. - Grammar and typo fixes to hmcdrv and tape drivers. * tag 's390-5.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits) Revert "s390/smp: enforce lowcore protection on CPU restart" Revert "s390/smp: rework absolute lowcore access" Revert "s390/smp,ptdump: add absolute lowcore markers" s390/unwind: fix fgraph return address recovery s390/nmi: use irqentry_nmi_enter()/irqentry_nmi_exit() s390: add ELF note type for encrypted CPU state of a PV VCPU s390/smp,ptdump: add absolute lowcore markers s390/smp: rework absolute lowcore access s390/setup: rearrange absolute lowcore initialization s390/boot: cleanup adjust_to_uv_max() function s390/smp: enforce lowcore protection on CPU restart s390/tape: fix comment typo s390/hmcdrv: fix Kconfig "its" grammar s390/docs: fix warnings for vfio_ap driver doc s390/docs: fix warnings for vfio_ap driver lock usage doc s390/crash: support multi-segment iterators s390/crash: use static swap buffer for copy_to_user_real() s390/crash: move copy_to_user_real() to crash_dump.c s390/zcore: fix race when reading from hardware system area s390/crash: fix incorrect number of bytes to copy to user space ...

Revert "s390/smp: enforce lowcore protection on CPU restart"

2022-08-06T07:29:46Z

This reverts commit 6f5c672d17f583b081e283927f5040f726c54598. This breaks normal crash dump when CPU0 is offline. Signed-off-by: Alexander Gordeev

Revert "s390/smp: rework absolute lowcore access"

2022-08-06T07:24:07Z

This reverts commit 7d06fed77b7d8fc9f6cc41b4e3f2823d32532ad8. This introduced vmem_mutex locking from vmem_map_4k_page() function called from smp_reinit_ipl_cpu() with interrupts disabled. While it is a pre-SMP early initcall no other CPUs running in parallel nor other code taking vmem_mutex on this boot stage - it still needs to be fixed. Signed-off-by: Alexander Gordeev

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2022-08-04T21:59:54Z

Pull kvm updates from Paolo Bonzini: "Quite a large pull request due to a selftest API overhaul and some patches that had come in too late for 5.19. ARM: - Unwinder implementations for both nVHE modes (classic and protected), complete with an overflow stack - Rework of the sysreg access from userspace, with a complete rewrite of the vgic-v3 view to allign with the rest of the infrastructure - Disagregation of the vcpu flags in separate sets to better track their use model. - A fix for the GICv2-on-v3 selftest - A small set of cosmetic fixes RISC-V: - Track ISA extensions used by Guest using bitmap - Added system instruction emulation framework - Added CSR emulation framework - Added gfp_custom flag in struct kvm_mmu_memory_cache - Added G-stage ioremap() and iounmap() functions - Added support for Svpbmt inside Guest s390: - add an interface to provide a hypervisor dump for secure guests - improve selftests to use TAP interface - enable interpretive execution of zPCI instructions (for PCI passthrough) - First part of deferred teardown - CPU Topology - PV attestation - Minor fixes x86: - Permit guests to ignore single-bit ECC errors - Intel IPI virtualization - Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS - PEBS virtualization - Simplify PMU emulation by just using PERF_TYPE_RAW events - More accurate event reinjection on SVM (avoid retrying instructions) - Allow getting/setting the state of the speaker port data bit - Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent - "Notify" VM exit (detect microarchitectural hangs) for Intel - Use try_cmpxchg64 instead of cmpxchg64 - Ignore benign host accesses to PMU MSRs when PMU is disabled - Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior - Allow NX huge page mitigation to be disabled on a per-vm basis - Port eager page splitting to shadow MMU as well - Enable CMCI capability by default and handle injected UCNA errors - Expose pid of vcpu threads in debugfs - x2AVIC support for AMD - cleanup PIO emulation - Fixes for LLDT/LTR emulation - Don't require refcounted "struct page" to create huge SPTEs - Miscellaneous cleanups: - MCE MSR emulation - Use separate namespaces for guest PTEs and shadow PTEs bitmasks - PIO emulation - Reorganize rmap API, mostly around rmap destruction - Do not workaround very old KVM bugs for L0 that runs with nesting enabled - new selftests API for CPUID Generic: - Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache - new selftests API using struct kvm_vcpu instead of a (vm, id) tuple" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (606 commits) selftests: kvm: set rax before vmcall selftests: KVM: Add exponent check for boolean stats selftests: KVM: Provide descriptive assertions in kvm_binary_stats_test selftests: KVM: Check stat name before other fields KVM: x86/mmu: remove unused variable RISC-V: KVM: Add support for Svpbmt inside Guest/VM RISC-V: KVM: Use PAGE_KERNEL_IO in kvm_riscv_gstage_ioremap() RISC-V: KVM: Add G-stage ioremap() and iounmap() functions KVM: Add gfp_custom flag in struct kvm_mmu_memory_cache RISC-V: KVM: Add extensible CSR emulation framework RISC-V: KVM: Add extensible system instruction emulation framework RISC-V: KVM: Factor-out instruction emulation into separate sources RISC-V: KVM: move preempt_disable() call in kvm_arch_vcpu_ioctl_run RISC-V: KVM: Make kvm_riscv_guest_timer_init a void function RISC-V: KVM: Fix variable spelling mistake RISC-V: KVM: Improve ISA extension by using a bitmap KVM, x86/mmu: Fix the comment around kvm_tdp_mmu_zap_leafs() KVM: SVM: Dump Virtual Machine Save Area (VMSA) to klog KVM: x86/mmu: Treat NX as a valid SPTE bit for NPT KVM: x86: Do not block APIC write for non ICR registers ...

Merge tag 'random-6.0-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

2022-08-03T00:31:35Z

Pull random number generator updates from Jason Donenfeld: "Though there's been a decent amount of RNG-related development during this last cycle, not all of it is coming through this tree, as this cycle saw a shift toward tackling early boot time seeding issues, which took place in other trees as well. Here's a summary of the various patches: - The CONFIG_ARCH_RANDOM .config option and the "nordrand" boot option have been removed, as they overlapped with the more widely supported and more sensible options, CONFIG_RANDOM_TRUST_CPU and "random.trust_cpu". This change allowed simplifying a bit of arch code. - x86's RDRAND boot time test has been made a bit more robust, with RDRAND disabled if it's clearly producing bogus results. This would be a tip.git commit, technically, but I took it through random.git to avoid a large merge conflict. - The RNG has long since mixed in a timestamp very early in boot, on the premise that a computer that does the same things, but does so starting at different points in wall time, could be made to still produce a different RNG state. Unfortunately, the clock isn't set early in boot on all systems, so now we mix in that timestamp when the time is actually set. - User Mode Linux now uses the host OS's getrandom() syscall to generate a bootloader RNG seed and later on treats getrandom() as the platform's RDRAND-like faculty. - The arch_get_random_{seed_,}_long() family of functions is now arch_get_random_{seed_,}_longs(), which enables certain platforms, such as s390, to exploit considerable performance advantages from requesting multiple CPU random numbers at once, while at the same time compiling down to the same code as before on platforms like x86. - A small cleanup changing a cmpxchg() into a try_cmpxchg(), from Uros. - A comment spelling fix" More info about other random number changes that come in through various architecture trees in the full commentary in the pull request: https://lore.kernel.org/all/20220731232428.2219258-1-Jason@zx2c4.com/ * tag 'random-6.0-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: random: correct spelling of "overwrites" random: handle archrandom with multiple longs um: seed rng using host OS rng random: use try_cmpxchg in _credit_init_bits timekeeping: contribute wall clock to rng on time change x86/rdrand: Remove "nordrand" flag in favor of "random.trust_cpu" random: remove CONFIG_ARCH_RANDOM