kernel/git/stable/linux-stable.git/arch/s390, branch linux-5.6.y

s390/pci: Log new handle in clp_disable_fh()

2020-06-17T14:41:52+00:00

[ Upstream commit e1750a3d9abbea2ece29cac8dc5a6f5bc19c1492 ] After disabling a function, the original handle is logged instead of the disabled handle. Link: https://lkml.kernel.org/r/20200522183922.5253-1-ptesarik@suse.com Fixes: 17cdec960cf7 ("s390/pci: Recover handle in clp_set_pci_fn()") Reviewed-by: Pierre Morel Signed-off-by: Petr Tesarik Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin

s390/mm: fix set_huge_pte_at() for empty ptes

2020-06-07T11:16:46+00:00

[ Upstream commit ac8372f3b4e41015549b331a4f350224661e7fc6 ] On s390, the layout of normal and large ptes (i.e. pmds/puds) differs. Therefore, set_huge_pte_at() does a conversion from a normal pte to the corresponding large pmd/pud. So, when converting an empty pte, this should result in an empty pmd/pud, which would return true for pmd/pud_none(). However, after conversion we also mark the pmd/pud as large, and therefore present. For empty ptes, this will result in an empty pmd/pud that is also marked as large, and pmd/pud_none() would not return true. There is currently no issue with this behaviour, as set_huge_pte_at() does not seem to be called for empty ptes. It would be valid though, so let's fix this by not marking empty ptes as large in set_huge_pte_at(). This was found by testing a patch from from Anshuman Khandual, which is currently discussed on LKML ("mm/debug: Add more arch page table helper tests"). Signed-off-by: Gerald Schaefer Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin

s390/kexec_file: fix initrd location for kdump kernel

2020-05-27T15:48:29+00:00

commit 70b690547d5ea1a3d135a4cc39cd1e08246d0c3a upstream. initrd_start must not point at the location the initrd is loaded into the crashkernel memory but at the location it will be after the crashkernel memory is swapped with the memory at 0. Fixes: ee337f5469fd ("s390/kexec_file: Add crash support to image loader") Reported-by: Lianbo Jiang Signed-off-by: Philipp Rudo Tested-by: Lianbo Jiang Link: https://lore.kernel.org/r/20200512193956.15ae3f23@laptop2-ibm.local Signed-off-by: Christian Borntraeger Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/kaslr: add support for R_390_JMP_SLOT relocation type

2020-05-27T15:48:25+00:00

commit 4c1cbcbd6c56c79de2c07159be4f55386bb0bef2 upstream. With certain kernel configurations, the R_390_JMP_SLOT relocation type might be generated, which is not expected by the KASLR relocation code, and the kernel stops with the message "Unknown relocation type". This was found with a zfcpdump kernel config, where CONFIG_MODULES=n and CONFIG_VFIO=n. In that case, symbol_get() is used on undefined __weak symbols in virt/kvm/vfio.c, which results in the generation of R_390_JMP_SLOT relocation types. Fix this by handling R_390_JMP_SLOT similar to R_390_GLOB_DAT. Fixes: 805bc0bc238f ("s390/kernel: build a relocatable kernel") Cc: # v5.2+ Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/pci: Fix s390_mmio_read/write with MIO

2020-05-27T15:48:25+00:00

commit f058599e22d59e594e5aae1dc10560568d8f4a8b upstream. The s390_mmio_read/write syscalls are currently broken when running with MIO. The new pcistb_mio/pcstg_mio/pcilg_mio instructions are executed similiarly to normal load/store instructions and do address translation in the current address space. That means inside the kernel they are aware of mappings into kernel address space while outside the kernel they use user space mappings (usually created through mmap'ing a PCI device file). Now when existing user space applications use the s390_pci_mmio_write and s390_pci_mmio_read syscalls, they pass I/O addresses that are mapped into user space so as to be usable with the new instructions without needing a syscall. Accessing these addresses with the old instructions as done currently leads to a kernel panic. Also, for such a user space mapping there may not exist an equivalent kernel space mapping which means we can't just use the new instructions in kernel space. Instead of replicating user mappings in the kernel which then might collide with other mappings, we can conceptually execute the new instructions as if executed by the user space application using the secondary address space. This even allows us to directly store to the user pointer without the need for copy_to/from_user(). Cc: stable@vger.kernel.org Fixes: 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") Signed-off-by: Niklas Schnelle Reviewed-by: Sven Schnelle Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

KVM: s390: Remove false WARN_ON_ONCE for the PQAP instruction

2020-05-14T05:59:22+00:00

commit 5615e74f48dcc982655543e979b6c3f3f877e6f6 upstream. In LPAR we will only get an intercept for FC==3 for the PQAP instruction. Running nested under z/VM can result in other intercepts as well as ECA_APIE is an effective bit: If one hypervisor layer has turned this bit off, the end result will be that we will get intercepts for all function codes. Usually the first one will be a query like PQAP(QCI). So the WARN_ON_ONCE is not right. Let us simply remove it. Cc: Pierre Morel Cc: Tony Krowiak Cc: stable@vger.kernel.org # v5.3+ Fixes: e5282de93105 ("s390: ap: kvm: add PQAP interception for AQIC") Link: https://lore.kernel.org/kvm/20200505083515.2720-1-borntraeger@de.ibm.com Reported-by: Qian Cai Signed-off-by: Christian Borntraeger Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

s390/pci: do not set affinity for floating irqs

2020-05-02T06:50:52+00:00

commit 86dbf32da150339ca81509fa2eb84c814b55258b upstream. with the introduction of CPU directed interrupts the kernel parameter pci=force_floating was introduced to fall back to the previous behavior using floating irqs. However we were still setting the affinity in that case, both in __irq_alloc_descs() and via the irq_set_affinity callback in struct irq_chip. For the former only set the affinity in the directed case. The latter is explicitly set in zpci_directed_irq_init() so we can just leave it unset for the floating case. Fixes: e979ce7bced2 ("s390/pci: provide support for CPU directed interrupts") Co-developed-by: Alexander Schmidt Signed-off-by: Alexander Schmidt Signed-off-by: Niklas Schnelle Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/ftrace: fix potential crashes when switching tracers

2020-05-02T06:50:43+00:00

commit 8ebf6da9db1b2a20bb86cc1bee2552e894d03308 upstream. Switching tracers include instruction patching. To prevent that a instruction is patched while it's read the instruction patching is done in stop_machine 'context'. This also means that any function called during stop_machine must not be traced. Thus add 'notrace' to all functions called within stop_machine. Fixes: 1ec2772e0c3c ("s390/diag: add a statistic for diagnose calls") Fixes: 38f2c691a4b3 ("s390: improve wait logic of stop_machine") Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield") Signed-off-by: Philipp Rudo Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/mm: fix page table upgrade vs 2ndary address mode accesses

2020-04-29T14:34:58+00:00

commit 316ec154810960052d4586b634156c54d0778f74 upstream. A page table upgrade in a kernel section that uses secondary address mode will mess up the kernel instructions as follows: Consider the following scenario: two threads are sharing memory. On CPU1 thread 1 does e.g. strnlen_user(). That gets to old_fs = enable_sacf_uaccess(); len = strnlen_user_srst(src, size); and " la %2,0(%1)\n" " la %3,0(%0,%1)\n" " slgr %0,%0\n" " sacf 256\n" "0: srst %3,%2\n" in strnlen_user_srst(). At that point we are in secondary space mode, control register 1 points to kernel page table and instruction fetching happens via c1, rather than usual c13. Interrupts are not disabled, for obvious reasons. On CPU2 thread 2 does MAP_FIXED mmap(), forcing the upgrade of page table from 3-level to e.g. 4-level one. We'd allocated new top-level table, set it up and now we hit this: notify = 1; spin_unlock_bh(&mm->page_table_lock); } if (notify) on_each_cpu(__crst_table_upgrade, mm, 0); OK, we need to actually change over to use of new page table and we need that to happen in all threads that are currently running. Which happens to include the thread 1. IPI is delivered and we have static void __crst_table_upgrade(void *arg) { struct mm_struct *mm = arg; if (current->active_mm == mm) set_user_asce(mm); __tlb_flush_local(); } run on CPU1. That does static inline void set_user_asce(struct mm_struct *mm) { S390_lowcore.user_asce = mm->context.asce; OK, user page table address updated... __ctl_load(S390_lowcore.user_asce, 1, 1); ... and control register 1 set to it. clear_cpu_flag(CIF_ASCE_PRIMARY); } IPI is run in home space mode, so it's fine - insns are fetched using c13, which always points to kernel page table. But as soon as we return from the interrupt, previous PSW is restored, putting CPU1 back into secondary space mode, at which point we no longer get the kernel instructions from the kernel mapping. The fix is to only fixup the control registers that are currently in use for user processes during the page table update. We must also disable interrupts in enable_sacf_uaccess to synchronize the cr and thread.mm_segment updates against the on_each-cpu. Fixes: 0aaba41b58bc ("s390: remove all code using the access register mode") Cc: stable@vger.kernel.org # 4.15+ Reported-by: Al Viro Reviewed-by: Gerald Schaefer References: CVE-2020-11884 Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

KVM: s390: Return last valid slot if approx index is out-of-bounds

2020-04-29T14:34:47+00:00

commit 97daa028f3f621adff2c4f7b15fe0874e5b5bd6c upstream. Return the index of the last valid slot from gfn_to_memslot_approx() if its binary search loop yielded an out-of-bounds index. The index can be out-of-bounds if the specified gfn is less than the base of the lowest memslot (which is also the last valid memslot). Note, the sole caller, kvm_s390_get_cmma(), ensures used_slots is non-zero. Fixes: afdad61615cc3 ("KVM: s390: Fix storage attributes migration with memory slots") Cc: stable@vger.kernel.org # 4.19.x: 0774a964ef56: KVM: Fix out of range accesses to memslots Cc: stable@vger.kernel.org # 4.19.x Signed-off-by: Sean Christopherson Message-Id: <20200408064059.8957-3-sean.j.christopherson@intel.com> Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman