kernel/git/stable/linux-stable.git/arch/s390, branch linux-4.5.y

s390/pci: add extra padding to function measurement block

2016-05-04T21:49:02+00:00

commit 9d89d9e61d361f3adb75e1aebe4bb367faf16cfa upstream. Newer machines might use a different (larger) format for function measurement blocks. To ensure that we comply with the alignment requirement on these machines and prevent memory corruption (when firmware writes more data than we expect) add 16 padding bytes at the end of the fmb. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390/mm: handle PTE-mapped tail pages in fast gup

2016-04-20T06:45:07+00:00

commit fc897c95e91451271cd707ee0f71022b9b201ce9 upstream. With the THP refcounting rework it is possible to see THP compound tail pages mapped with PTEs during a THP split. This needs to be considered when using page_cache_get_speculative(), which will always fail on tail pages because ->_count is always zero. commit 7aef4172 "mm: handle PTE-mapped tail pages in gerneric fast gup implementaiton" fixed it for the generic fast gup code by using compound_head(page) instead of page, but not for s390. This patch is a 1:1 adaption of commit 7aef4172 for the s390 fast gup code. Without this fix, gup will fall back to the slow path or fail in the unlikely scenario that we hit a THP under splitting in-between the page table split and the compound page split. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390/pci: enforce fmb page boundary rule

2016-04-12T14:33:15+00:00

commit 80c544ded25ac14d7cc3e555abb8ed2c2da99b84 upstream. The function measurement block must not cross a page boundary. Ensure that by raising the alignment requirement to the smallest power of 2 larger than the size of the fmb. Fixes: d0b088531 ("s390/pci: performance statistics and debug infrastructure") Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390/cpumf: add missing lpp magic initialization

2016-04-12T14:33:15+00:00

commit 8f100bb1ff27873dd71f636da670e503b9ade3c6 upstream. Add the missing lpp magic initialization for cpu 0. Without this all samples on cpu 0 do not have the most significant bit set in the program parameter field, which we use to distinguish between guest and host samples if the pid is also 0. We did initialize the lpp magic in the absolute zero lowcore but forgot that when switching to the allocated lowcore on cpu 0 only. Reported-by: Shu Juan Zhang Acked-by: Christian Borntraeger Fixes: e22cf8ca6f75 ("s390/cpumf: rework program parameter setting to detect guest samples") Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390: fix floating pointer register corruption (again)

2016-04-12T14:33:15+00:00

commit e370e4769463a65dcf8806fa26d2874e0542ac41 upstream. There is a tricky interaction between the machine check handler and the critical sections of load_fpu_regs and save_fpu_regs functions. If the machine check interrupts one of the two functions the critical section cleanup will complete the function before the machine check handler s390_do_machine_check is called. Trouble is that the machine check handler needs to validate the floating point registers *before* and not *after* the completion of load_fpu_regs/save_fpu_regs. The simplest solution is to rewind the PSW to the start of the load_fpu_regs/save_fpu_regs and retry the function after the return from the machine check handler. Tested-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

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

2016-03-10T18:42:15+00:00

Pull KVM fixes from Paolo Bonzini: "A few simple fixes for ARM, x86, PPC and generic code. The x86 MMU fix is a bit larger because the surrounding code needed a cleanup, but nothing worrisome" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: MMU: fix reserved bit check for ept=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 KVM: MMU: fix ept=0/pte.u=1/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 combo kvm: cap halt polling at exactly halt_poll_ns KVM: s390: correct fprs on SIGP (STOP AND) STORE STATUS KVM: VMX: disable PEBS before a guest entry KVM: PPC: Book3S HV: Sanitize special-purpose register values on guest exit

s390/mm: four page table levels vs. fork

2016-03-10T08:21:24+00:00

The fork of a process with four page table levels is broken since git commit 6252d702c5311ce9 "[S390] dynamic page tables." All new mm contexts are created with three page table levels and an asce limit of 4TB. If the parent has four levels dup_mmap will add vmas to the new context which are outside of the asce limit. The subsequent call to copy_page_range will walk the three level page table structure of the new process with non-zero pgd and pud indexes. This leads to memory clobbers as the pgd_index *and* the pud_index is added to the mm->pgd pointer without a pgd_deref in between. The init_new_context() function is selecting the number of page table levels for a new context. The function is used by mm_init() which in turn is called by dup_mm() and mm_alloc(). These two are used by fork() and exec(). The init_new_context() function can distinguish the two cases by looking at mm->context.asce_limit, for fork() the mm struct has been copied and the number of page table levels may not change. For exec() the mm_alloc() function set the new mm structure to zero, in this case a three-level page table is created as the temporary stack space is located at STACK_TOP_MAX = 4TB. This fixes CVE-2016-2143. Reported-by: Marcin Kościelnicki Reviewed-by: Heiko Carstens Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky

KVM: s390: correct fprs on SIGP (STOP AND) STORE STATUS

2016-03-08T11:47:01+00:00

With MACHINE_HAS_VX, we convert the floating point registers from the vector registeres when storing the status. For other VCPUs, these are stored to vcpu->run->s.regs.vrs, but we are using current->thread.fpu.vxrs, which resolves to the currently loaded VCPU. So kvm_s390_store_status_unloaded() currently writes the wrong floating point registers (converted from the vector registers) when called from another VCPU on a z13. This is only the case for old user space not handling SIGP STORE STATUS and SIGP STOP AND STORE STATUS, but relying on the kernel implementation. All other calls come from the loaded VCPU via kvm_s390_store_status(). Fixes: 9abc2a08a7d6 (KVM: s390: fix memory overwrites when vx is disabled) Reviewed-by: Christian Borntraeger Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger Signed-off-by: Paolo Bonzini

s390/cpumf: Fix lpp detection

2016-03-08T09:38:06+00:00

we have to check bit 40 of the facility list before issuing LPP and not bit 48. Otherwise a guest running on a system with "The decimal-floating-point zoned-conversion facility" and without the "The set-program-parameters facility" might crash on an lpp instruction. Signed-off-by: Christian Borntraeger Cc: stable@vger.kernel.org # v4.4+ Fixes: e22cf8ca6f75 ("s390/cpumf: rework program parameter setting to detect guest samples") Signed-off-by: Martin Schwidefsky

s390/fpu: signals vs. floating point control register

2016-02-22T08:29:35+00:00

git commit 904818e2f229f3d94ec95f6932a6358c81e73d78 "s390/kernel: introduce fpu-internal.h with fpu helper functions" introduced the fpregs_store / fp_regs_load helper. These function fail to save and restore the floating pointer control registers. The effect is that the FPC is not correctly handled on signal delivery and signal return. Cc: stable@vger.kernel.org # 4.4 Signed-off-by: Martin Schwidefsky