1. 12 Apr, 2019 7 commits
    • Sebastian Andrzej Siewior's avatar
      x86/pkeys: Add PKRU value to init_fpstate · a5eff725
      Sebastian Andrzej Siewior authored
      The task's initial PKRU value is set partly for fpu__clear()/
      copy_init_pkru_to_fpregs(). It is not part of init_fpstate.xsave and
      instead it is set explicitly.
      
      If the user removes the PKRU state from XSAVE in the signal handler then
      __fpu__restore_sig() will restore the missing bits from `init_fpstate'
      and initialize the PKRU value to 0.
      
      Add the `init_pkru_value' to `init_fpstate' so it is set to the init
      value in such a case.
      
      In theory copy_init_pkru_to_fpregs() could be removed because restoring
      the PKRU at return-to-userland should be enough.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
      Cc: Dominik Brodowski <linux@dominikbrodowski.net>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-28-bigeasy@linutronix.de
      a5eff725
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Restore regs in copy_fpstate_to_sigframe() in order to use the fastpath · 06b251df
      Sebastian Andrzej Siewior authored
      If a task is scheduled out and receives a signal then it won't be
      able to take the fastpath because the registers aren't available. The
      slowpath is more expensive compared to XRSTOR + XSAVE which usually
      succeeds.
      
      Here are some clock_gettime() numbers from a bigger box with AVX512
      during bootup:
      
      - __fpregs_load_activate() takes 140ns - 350ns. If it was the most recent
        FPU context on the CPU then the optimisation in __fpregs_load_activate()
        will skip the load (which was disabled during the test).
      
      - copy_fpregs_to_sigframe() takes 200ns - 450ns if it succeeds. On a
        pagefault it is 1.8us - 3us usually in the 2.6us area.
      
      - The slowpath takes 1.5us - 6us. Usually in the 2.6us area.
      
      My testcases (including lat_sig) take the fastpath without
      __fpregs_load_activate(). I expect this to be the majority.
      
      Since the slowpath is in the >1us area it makes sense to load the
      registers and attempt to save them directly. The direct save may fail
      but should only happen on the first invocation or after fork() while the
      page is read-only.
      
       [ bp: Massage a bit. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-27-bigeasy@linutronix.de
      06b251df
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Add a fastpath to copy_fpstate_to_sigframe() · da2f32fb
      Sebastian Andrzej Siewior authored
      Try to save the FPU registers directly to the userland stack frame if
      the CPU holds the FPU registers for the current task. This has to be
      done with the pagefault disabled because we can't fault (while the FPU
      registers are locked) and therefore the operation might fail. If it
      fails try the slowpath which can handle faults.
      
       [ bp: Massage a bit. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-26-bigeasy@linutronix.de
      da2f32fb
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Add a fastpath to __fpu__restore_sig() · 1d731e73
      Sebastian Andrzej Siewior authored
      The previous commits refactor the restoration of the FPU registers so
      that they can be loaded from in-kernel memory. This overhead can be
      avoided if the load can be performed without a pagefault.
      
      Attempt to restore FPU registers by invoking
      copy_user_to_fpregs_zeroing(). If it fails try the slowpath which can
      handle pagefaults.
      
       [ bp: Add a comment over the fastpath to be able to find one's way
         around the function. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-25-bigeasy@linutronix.de
      1d731e73
    • Rik van Riel's avatar
      x86/fpu: Defer FPU state load until return to userspace · 5f409e20
      Rik van Riel authored
      Defer loading of FPU state until return to userspace. This gives
      the kernel the potential to skip loading FPU state for tasks that
      stay in kernel mode, or for tasks that end up with repeated
      invocations of kernel_fpu_begin() & kernel_fpu_end().
      
      The fpregs_lock/unlock() section ensures that the registers remain
      unchanged. Otherwise a context switch or a bottom half could save the
      registers to its FPU context and the processor's FPU registers would
      became random if modified at the same time.
      
      KVM swaps the host/guest registers on entry/exit path. This flow has
      been kept as is. First it ensures that the registers are loaded and then
      saves the current (host) state before it loads the guest's registers. The
      swap is done at the very end with disabled interrupts so it should not
      change anymore before theg guest is entered. The read/save version seems
      to be cheaper compared to memcpy() in a micro benchmark.
      
      Each thread gets TIF_NEED_FPU_LOAD set as part of fork() / fpu__copy().
      For kernel threads, this flag gets never cleared which avoids saving /
      restoring the FPU state for kernel threads and during in-kernel usage of
      the FPU registers.
      
       [
         bp: Correct and update commit message and fix checkpatch warnings.
         s/register/registers/ where it is used in plural.
         minor comment corrections.
         remove unused trace_x86_fpu_activate_state() TP.
       ]
      Signed-off-by: default avatarRik van Riel <riel@surriel.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: Babu Moger <Babu.Moger@amd.com>
      Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
      Cc: Dmitry Safonov <dima@arista.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: Joerg Roedel <jroedel@suse.de>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Nicolai Stange <nstange@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: "Radim Krčmář" <rkrcmar@redhat.com>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: Waiman Long <longman@redhat.com>
      Cc: x86-ml <x86@kernel.org>
      Cc: Yi Wang <wang.yi59@zte.com.cn>
      Link: https://lkml.kernel.org/r/20190403164156.19645-24-bigeasy@linutronix.de
      5f409e20
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Merge the two code paths in __fpu__restore_sig() · c2ff9e9a
      Sebastian Andrzej Siewior authored
      The ia32_fxstate case (32bit with fxsr) and the other (64bit frames or
      32bit frames without fxsr) restore both from kernel memory and sanitize
      the content.
      
      The !ia32_fxstate version restores missing xstates from "init state"
      while the ia32_fxstate doesn't and skips it.
      
      Merge the two code paths and keep the !ia32_fxstate one. Copy only the
      user_i387_ia32_struct data structure in the ia32_fxstate.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-23-bigeasy@linutronix.de
      c2ff9e9a
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Restore from kernel memory on the 64-bit path too · 926b21f3
      Sebastian Andrzej Siewior authored
      The 64-bit case (both 64-bit and 32-bit frames) loads the new state from
      user memory.
      
      However, doing this is not desired if the FPU state is going to be
      restored on return to userland: it would be required to disable
      preemption in order to avoid a context switch which would set
      TIF_NEED_FPU_LOAD. If this happens before the restore operation then the
      loaded registers would become volatile.
      
      Furthermore, disabling preemption while accessing user memory requires
      to disable the pagefault handler. An error during FXRSTOR would then
      mean that either a page fault occurred (and it would have to be retried
      with enabled page fault handler) or a #GP occurred because the xstate is
      bogus (after all, the signal handler can modify it).
      
      In order to avoid that mess, copy the FPU state from userland, validate
      it and then load it. The copy_kernel_…() helpers are basically just
      like the old helpers except that they operate on kernel memory and the
      fault handler just sets the error value and the caller handles it.
      
      copy_user_to_fpregs_zeroing() and its helpers remain and will be used
      later for a fastpath optimisation.
      
       [ bp: Clarify commit message. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-22-bigeasy@linutronix.de
      926b21f3
  2. 11 Apr, 2019 9 commits
  3. 10 Apr, 2019 6 commits
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Use a feature number instead of mask in two more helpers · abd16d68
      Sebastian Andrzej Siewior authored
      After changing the argument of __raw_xsave_addr() from a mask to
      number Dave suggested to check if it makes sense to do the same for
      get_xsave_addr(). As it turns out it does.
      
      Only get_xsave_addr() needs the mask to check if the requested feature
      is part of what is supported/saved and then uses the number again. The
      shift operation is cheaper compared to fls64() (find last bit set).
      Also, the feature number uses less opcode space compared to the mask. :)
      
      Make the get_xsave_addr() argument a xfeature number instead of a mask
      and fix up its callers.
      
      Furthermore, use xfeature_nr and xfeature_mask consistently.
      
      This results in the following changes to the kvm code:
      
        feature -> xfeature_mask
        index -> xfeature_nr
      Suggested-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: "Radim Krčmář" <rkrcmar@redhat.com>
      Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Siarhei Liakh <Siarhei.Liakh@concurrent-rt.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-12-bigeasy@linutronix.de
      abd16d68
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Make __raw_xsave_addr() use a feature number instead of mask · 07baeb04
      Sebastian Andrzej Siewior authored
      Most users of __raw_xsave_addr() use a feature number, shift it to a
      mask and then __raw_xsave_addr() shifts it back to the feature number.
      
      Make __raw_xsave_addr() use the feature number as an argument.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-11-bigeasy@linutronix.de
      07baeb04
    • Rik van Riel's avatar
      x86/fpu: Add an __fpregs_load_activate() internal helper · 4ee91519
      Rik van Riel authored
      Add a helper function that ensures the floating point registers for the
      current task are active. Use with preemption disabled.
      
      While at it, add fpregs_lock/unlock() helpers too, to be used in later
      patches.
      
       [ bp: Add a comment about its intended usage. ]
      Signed-off-by: default avatarRik van Riel <riel@surriel.com>
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-10-bigeasy@linutronix.de
      4ee91519
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Remove user_fpu_begin() · 0169f53e
      Sebastian Andrzej Siewior authored
      user_fpu_begin() sets fpu_fpregs_owner_ctx to task's fpu struct. This is
      always the case since there is no lazy FPU anymore.
      
      fpu_fpregs_owner_ctx is used during context switch to decide if it needs
      to load the saved registers or if the currently loaded registers are
      valid. It could be skipped during a
      
        taskA -> kernel thread -> taskA
      
      switch because the switch to the kernel thread would not alter the CPU's
      sFPU tate.
      
      Since this field is always updated during context switch and
      never invalidated, setting it manually (in user context) makes no
      difference. A kernel thread with kernel_fpu_begin() block could
      set fpu_fpregs_owner_ctx to NULL but a kernel thread does not use
      user_fpu_begin().
      
      This is a leftover from the lazy-FPU time.
      
      Remove user_fpu_begin(), it does not change fpu_fpregs_owner_ctx's
      content.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Nicolai Stange <nstange@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-9-bigeasy@linutronix.de
      0169f53e
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Remove fpu->initialized · 2722146e
      Sebastian Andrzej Siewior authored
      The struct fpu.initialized member is always set to one for user tasks
      and zero for kernel tasks. This avoids saving/restoring the FPU
      registers for kernel threads.
      
      The ->initialized = 0 case for user tasks has been removed in previous
      changes, for instance, by doing an explicit unconditional init at fork()
      time for FPU-less systems which was otherwise delayed until the emulated
      opcode.
      
      The context switch code (switch_fpu_prepare() + switch_fpu_finish())
      can't unconditionally save/restore registers for kernel threads. Not
      only would it slow down the switch but also load a zeroed xcomp_bv for
      XSAVES.
      
      For kernel_fpu_begin() (+end) the situation is similar: EFI with runtime
      services uses this before alternatives_patched is true. Which means that
      this function is used too early and it wasn't the case before.
      
      For those two cases, use current->mm to distinguish between user and
      kernel thread. For kernel_fpu_begin() skip save/restore of the FPU
      registers.
      
      During the context switch into a kernel thread don't do anything. There
      is no reason to save the FPU state of a kernel thread.
      
      The reordering in __switch_to() is important because the current()
      pointer needs to be valid before switch_fpu_finish() is invoked so ->mm
      is seen of the new task instead the old one.
      
      N.B.: fpu__save() doesn't need to check ->mm because it is called by
      user tasks only.
      
       [ bp: Massage. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: Babu Moger <Babu.Moger@amd.com>
      Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
      Cc: Dmitry Safonov <dima@arista.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: Joerg Roedel <jroedel@suse.de>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Nicolai Stange <nstange@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-8-bigeasy@linutronix.de
      2722146e
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Don't save fxregs for ia32 frames in copy_fpstate_to_sigframe() · 39388e80
      Sebastian Andrzej Siewior authored
      In commit
      
        72a671ce ("x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels")
      
      the 32bit and 64bit path of the signal delivery code were merged.
      
      The 32bit version:
      
        int save_i387_xstate_ia32(void __user *buf)
        …
               if (cpu_has_xsave)
                       return save_i387_xsave(fp);
               if (cpu_has_fxsr)
                       return save_i387_fxsave(fp);
      
      The 64bit version:
      
        int save_i387_xstate(void __user *buf)
        …
               if (user_has_fpu()) {
                       if (use_xsave())
                               err = xsave_user(buf);
                       else
                               err = fxsave_user(buf);
      
                       if (unlikely(err)) {
                               __clear_user(buf, xstate_size);
                               return err;
      
      The merge:
      
        int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
        …
               if (user_has_fpu()) {
                       /* Save the live register state to the user directly. */
                       if (save_user_xstate(buf_fx))
                               return -1;
                       /* Update the thread's fxstate to save the fsave header. */
                       if (ia32_fxstate)
                               fpu_fxsave(&tsk->thread.fpu);
      
      I don't think that we needed to save the FPU registers to ->thread.fpu
      because the registers were stored in buf_fx. Today the state will be
      restored from buf_fx after the signal was handled (I assume that this
      was also the case with lazy-FPU).
      
      Since commit
      
        66463db4 ("x86, fpu: shift drop_init_fpu() from save_xstate_sig() to handle_signal()")
      
      it is ensured that the signal handler starts with clear/fresh set of FPU
      registers which means that the previous store is futile.
      
      Remove the copy_fxregs_to_kernel() call because task's FPU state is
      cleared later in handle_signal() via fpu__clear().
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-7-bigeasy@linutronix.de
      39388e80
  4. 09 Apr, 2019 5 commits
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() · fbcc9e0c
      Sebastian Andrzej Siewior authored
      With lazy-FPU support the (now named variable) ->initialized was set to
      true if the CPU's FPU registers were holding a valid state of the
      FPU registers for the active process. If it was set to false then the
      FPU state was saved in fpu->state and the FPU was deactivated.
      
      With lazy-FPU gone, ->initialized is always true for user threads and
      kernel threads never call this function so ->initialized is always true
      in copy_fpstate_to_sigframe().
      
      The using_compacted_format() check is also a leftover from the lazy-FPU
      time. In the
      
        ->initialized == false
      
      case copy_to_user() would copy the compacted buffer while userland would
      expect the non-compacted format instead. So in order to save the FPU
      state in the non-compacted form it issues XSAVE to save the *current*
      FPU state.
      
      If the FPU is not enabled, the attempt raises the FPU trap, the trap
      restores the FPU contents and re-enables the FPU and XSAVE is invoked
      again and succeeds.
      
      *This* does not longer work since commit
      
        bef8b6da ("x86/fpu: Handle #NM without FPU emulation as an error")
      
      Remove the check for ->initialized because it is always true and remove
      the false condition. Update the comment to reflect that the state is
      always live.
      
       [ bp: Massage. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-6-bigeasy@linutronix.de
      fbcc9e0c
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Always init the state in fpu__clear() · 88f5260a
      Sebastian Andrzej Siewior authored
      fpu__clear() only initializes the state if the CPU has FPU support.
      This initialisation is also required for FPU-less systems and takes
      place in math_emulate(). Since fpu__initialize() only performs the
      initialization if ->initialized is zero it does not matter that it
      is invoked each time an opcode is emulated. It makes the removal of
      ->initialized easier if the struct is also initialized in the FPU-less
      case at the same time.
      
      Move fpu__initialize() before the FPU feature check so it is also
      performed in the FPU-less case too.
      
       [ bp: Massage a bit. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: Bill Metzenthen <billm@melbpc.org.au>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Nicolai Stange <nstange@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-5-bigeasy@linutronix.de
      88f5260a
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Remove preempt_disable() in fpu__clear() · 60e528d6
      Sebastian Andrzej Siewior authored
      The preempt_disable() section was introduced in commit
      
        a10b6a16 ("x86/fpu: Make the fpu state change in fpu__clear() scheduler-atomic")
      
      and it was said to be temporary.
      
      fpu__initialize() initializes the FPU struct to its initial value and
      then sets ->initialized to 1. The last part is the important one.
      The content of the state does not matter because it gets set via
      copy_init_fpstate_to_fpregs().
      
      A preemption here has little meaning because the registers will always be
      set to the same content after copy_init_fpstate_to_fpregs(). A softirq
      with a kernel_fpu_begin() could also force to save FPU's registers after
      fpu__initialize() without changing the outcome here.
      
      Remove the preempt_disable() section in fpu__clear(), preemption here
      does not hurt.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Nicolai Stange <nstange@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-4-bigeasy@linutronix.de
      60e528d6
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Remove fpu__restore() · 6dd677a0
      Sebastian Andrzej Siewior authored
      There are no users of fpu__restore() so it is time to remove it. The
      comment regarding fpu__restore() and TS bit is stale since commit
      
        b3b0870e ("i387: do not preload FPU state at task switch time")
      
      and has no meaning since.
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Aubrey Li <aubrey.li@intel.com>
      Cc: Babu Moger <Babu.Moger@amd.com>
      Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
      Cc: Dmitry Safonov <dima@arista.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: Joerg Roedel <jroedel@suse.de>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: linux-doc@vger.kernel.org
      Cc: Nicolai Stange <nstange@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-3-bigeasy@linutronix.de
      6dd677a0
    • Sebastian Andrzej Siewior's avatar
      x86/fpu: Remove fpu->initialized usage in __fpu__restore_sig() · 39ea9baf
      Sebastian Andrzej Siewior authored
      This is a preparation for the removal of the ->initialized member in the
      fpu struct.
      
      __fpu__restore_sig() is deactivating the FPU via fpu__drop() and then
      setting manually ->initialized followed by fpu__restore(). The result is
      that it is possible to manipulate fpu->state and the state of registers
      won't be saved/restored on a context switch which would overwrite
      fpu->state:
      
      fpu__drop(fpu):
        ...
        fpu->initialized = 0;
        preempt_enable();
      
        <--- context switch
      
      Don't access the fpu->state while the content is read from user space
      and examined/sanitized. Use a temporary kmalloc() buffer for the
      preparation of the FPU registers and once the state is considered okay,
      load it. Should something go wrong, return with an error and without
      altering the original FPU registers.
      
      The removal of fpu__initialize() is a nop because fpu->initialized is
      already set for the user task.
      
       [ bp: Massage a bit. ]
      Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Reviewed-by: default avatarDave Hansen <dave.hansen@intel.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Acked-by: default avatarBorislav Petkov <bp@suse.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jann Horn <jannh@google.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: kvm ML <kvm@vger.kernel.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Cc: Rik van Riel <riel@surriel.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190403164156.19645-2-bigeasy@linutronix.de
      39ea9baf
  5. 03 Apr, 2019 1 commit
    • Jann Horn's avatar
      x86/fpu: Fix __user annotations · 89833fab
      Jann Horn authored
      In save_xstate_epilog(), use __user when type-casting userspace
      pointers.
      
      In setup_sigcontext() and x32_setup_rt_frame(), cast the userspace
      pointers to 'unsigned long __user *' before writing into them. These
      pointers are originally '__u32 __user *' or '__u64 __user *', causing
      sparse to complain when a userspace pointer is written into them. The
      casts are okay because the pointers always point to pointer-sized
      values.
      
      Thanks to Luc Van Oostenryck and Al Viro for explaining this to me.
      Signed-off-by: default avatarJann Horn <jannh@google.com>
      Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Mukesh Ojha <mojha@codeaurora.org>
      Cc: Qiaowei Ren <qiaowei.ren@intel.com>
      Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: x86-ml <x86@kernel.org>
      Link: https://lkml.kernel.org/r/20190329214652.258477-3-jannh@google.com
      89833fab
  6. 31 Mar, 2019 9 commits
    • Linus Torvalds's avatar
      Linux 5.1-rc3 · 79a3aaa7
      Linus Torvalds authored
      79a3aaa7
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 63fc9c23
      Linus Torvalds authored
      Pull KVM fixes from Paolo Bonzini:
       "A collection of x86 and ARM bugfixes, and some improvements to
        documentation.
      
        On top of this, a cleanup of kvm_para.h headers, which were exported
        by some architectures even though they not support KVM at all. This is
        responsible for all the Kbuild changes in the diffstat"
      
      * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
        Documentation: kvm: clarify KVM_SET_USER_MEMORY_REGION
        KVM: doc: Document the life cycle of a VM and its resources
        KVM: selftests: complete IO before migrating guest state
        KVM: selftests: disable stack protector for all KVM tests
        KVM: selftests: explicitly disable PIE for tests
        KVM: selftests: assert on exit reason in CR4/cpuid sync test
        KVM: x86: update %rip after emulating IO
        x86/kvm/hyper-v: avoid spurious pending stimer on vCPU init
        kvm/x86: Move MSR_IA32_ARCH_CAPABILITIES to array emulated_msrs
        KVM: x86: Emulate MSR_IA32_ARCH_CAPABILITIES on AMD hosts
        kvm: don't redefine flags as something else
        kvm: mmu: Used range based flushing in slot_handle_level_range
        KVM: export <linux/kvm_para.h> and <asm/kvm_para.h> iif KVM is supported
        KVM: x86: remove check on nr_mmu_pages in kvm_arch_commit_memory_region()
        kvm: nVMX: Add a vmentry check for HOST_SYSENTER_ESP and HOST_SYSENTER_EIP fields
        KVM: SVM: Workaround errata#1096 (insn_len maybe zero on SMAP violation)
        KVM: Reject device ioctls from processes other than the VM's creator
        KVM: doc: Fix incorrect word ordering regarding supported use of APIs
        KVM: x86: fix handling of role.cr4_pae and rename it to 'gpte_size'
        KVM: nVMX: Do not inherit quadrant and invalid for the root shadow EPT
        ...
      63fc9c23
    • Linus Torvalds's avatar
      Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 915ee0da
      Linus Torvalds authored
      Pull x86 fixes from Thomas Gleixner:
       "A pile of x86 updates:
      
         - Prevent exceeding he valid physical address space in the /dev/mem
           limit checks.
      
         - Move all header content inside the header guard to prevent compile
           failures.
      
         - Fix the bogus __percpu annotation in this_cpu_has() which makes
           sparse very noisy.
      
         - Disable switch jump tables completely when retpolines are enabled.
      
         - Prevent leaking the trampoline address"
      
      * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/realmode: Make set_real_mode_mem() static inline
        x86/cpufeature: Fix __percpu annotation in this_cpu_has()
        x86/mm: Don't exceed the valid physical address space
        x86/retpolines: Disable switch jump tables when retpolines are enabled
        x86/realmode: Don't leak the trampoline kernel address
        x86/boot: Fix incorrect ifdeffery scope
        x86/resctrl: Remove unused variable
      915ee0da
    • Linus Torvalds's avatar
      Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 590627f7
      Linus Torvalds authored
      Pull perf tooling fixes from Thomas Gleixner:
       "Core libraries:
         - Fix max perf_event_attr.precise_ip detection.
         - Fix parser error for uncore event alias
         - Fixup ordering of kernel maps after obtaining the main kernel map
           address.
      
        Intel PT:
         - Fix TSC slip where A TSC packet can slip past MTC packets so that
           the timestamp appears to go backwards.
         - Fixes for exported-sql-viewer GUI conversion to python3.
      
        ARM coresight:
         - Fix the build by adding a missing case value for enumeration value
           introduced in newer library, that now is the required one.
      
        tool headers:
         - Syncronize kernel headers with the kernel, getting new io_uring and
           pidfd_send_signal syscalls so that 'perf trace' can handle them"
      
      * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        perf pmu: Fix parser error for uncore event alias
        perf scripts python: exported-sql-viewer.py: Fix python3 support
        perf scripts python: exported-sql-viewer.py: Fix never-ending loop
        perf machine: Update kernel map address and re-order properly
        tools headers uapi: Sync powerpc's asm/kvm.h copy with the kernel sources
        tools headers: Update x86's syscall_64.tbl and uapi/asm-generic/unistd
        tools headers uapi: Update drm/i915_drm.h
        tools arch x86: Sync asm/cpufeatures.h with the kernel sources
        tools headers uapi: Sync linux/fcntl.h to get the F_SEAL_FUTURE_WRITE addition
        tools headers uapi: Sync asm-generic/mman-common.h and linux/mman.h
        perf evsel: Fix max perf_event_attr.precise_ip detection
        perf intel-pt: Fix TSC slip
        perf cs-etm: Add missing case value
      590627f7
    • Linus Torvalds's avatar
      Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · c29d8541
      Linus Torvalds authored
      Pull CPU hotplug fixes from Thomas Gleixner:
       "Two SMT/hotplug related fixes:
      
         - Prevent crash when HOTPLUG_CPU is disabled and the CPU bringup
           aborts. This is triggered with the 'nosmt' command line option, but
           can happen by any abort condition. As the real unplug code is not
           compiled in, prevent the fail by keeping the CPU in zombie state.
      
         - Enforce HOTPLUG_CPU for SMP on x86 to avoid the above situation
           completely. With 'nosmt' being a popular option it's required to
           unplug the half brought up sibling CPUs (due to the MCE wreckage)
           completely"
      
      * 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/smp: Enforce CONFIG_HOTPLUG_CPU when SMP=y
        cpu/hotplug: Prevent crash when CPU bringup fails on CONFIG_HOTPLUG_CPU=n
      c29d8541
    • Linus Torvalds's avatar
      Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 573efdc5
      Linus Torvalds authored
      Pull locking fixlet from Thomas Gleixner:
       "Trivial update to the maintainers file"
      
      * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        MAINTAINERS: Remove deleted file from futex file pattern
      573efdc5
    • Linus Torvalds's avatar
      Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · f78b5be2
      Linus Torvalds authored
      Pull core fixes from Thomas Gleixner:
       "A small set of core updates:
      
         - Make the watchdog respect the selected CPU mask again. That was
           broken by the rework of the watchdog thread management and caused
           inconsistent state and NMI watchdog being unstoppable.
      
         - Ensure that the objtool build can find the libelf location.
      
         - Remove dead kcore stub code"
      
      * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        watchdog: Respect watchdog cpumask on CPU hotplug
        objtool: Query pkg-config for libelf location
        proc/kcore: Remove unused kclist_add_remap()
      f78b5be2
    • Linus Torvalds's avatar
      Merge tag 'powerpc-5.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · 6536c5f2
      Linus Torvalds authored
      Pull powerpc fixes from Michael Ellerman:
       "Three non-regression fixes.
      
         - Our optimised memcmp could read past the end of one of the buffers
           and potentially trigger a page fault leading to an oops.
      
         - Some of our code to read energy management data on PowerVM had an
           endian bug leading to bogus results.
      
         - When reporting a machine check exception we incorrectly reported
           TLB multihits as D-Cache multhits due to a missing entry in the
           array of causes.
      
        Thanks to: Chandan Rajendra, Gautham R. Shenoy, Mahesh Salgaonkar,
        Segher Boessenkool, Vaidyanathan Srinivasan"
      
      * tag 'powerpc-5.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc/pseries/mce: Fix misleading print for TLB mutlihit
        powerpc/pseries/energy: Use OF accessor functions to read ibm,drc-indexes
        powerpc/64: Fix memcmp reading past the end of src/dest
      6536c5f2
    • Linus Torvalds's avatar
      Merge tag 'dmaengine-fix-5.1-rc3' of git://git.infradead.org/users/vkoul/slave-dma · c877b3df
      Linus Torvalds authored
      Pull dmaengine fixes from Vinod Koul:
      
       - Revert "dmaengine: stm32-mdma: Add a check on read_u32_array" as that
         caused regression
      
       - Fix MAINTAINER file uniphier-mdmac.c file path
      
      * tag 'dmaengine-fix-5.1-rc3' of git://git.infradead.org/users/vkoul/slave-dma:
        MAINTAINERS: Fix uniphier-mdmac.c file path
        dmaengine: stm32-mdma: Revert "dmaengine: stm32-mdma: Add a check on read_u32_array"
      c877b3df
  7. 30 Mar, 2019 3 commits
    • Linus Torvalds's avatar
      Merge tag 'led-fixes-for-5.1-rc3' of... · b5c8314f
      Linus Torvalds authored
      Merge tag 'led-fixes-for-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds
      
      Pull LED fixes from Jacek Anaszewski:
      
       - fix refcnt leak on interface rename
      
       - use memcpy in device_name_store() to avoid including garbage from a
         previous, longer value in the device_name
      
       - fix a potential NULL pointer dereference in case of_match_device()
         cannot find a match
      
      * tag 'led-fixes-for-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
        leds: trigger: netdev: use memcpy in device_name_store
        leds: pca9532: fix a potential NULL pointer dereference
        leds: trigger: netdev: fix refcnt leak on interface rename
      b5c8314f
    • Linus Torvalds's avatar
      Merge tag 'gpio-v5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio · 3af9a525
      Linus Torvalds authored
      Pull GPIO fixes from Linus Walleij:
       "As you can see [in the git history] I was away on leave and Bartosz
        kindly stepped in and collected a slew of fixes, I pulled them into my
        tree in two sets and merged some two more fixes (fixing my own caused
        bugs) on top.
      
        Summary:
      
         - Revert the extended use of gpio_set_config() and think about how we
           can do this properly.
      
         - Fix up the SPI CS GPIO handling so it now works properly on the SPI
           bus children, as intended.
      
         - Error paths and driver fixes"
      
      * tag 'gpio-v5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
        gpio: mockup: use simple_read_from_buffer() in debugfs read callback
        gpio: of: Fix of_gpiochip_add() error path
        gpio: of: Check for "spi-cs-high" in child instead of parent node
        gpio: of: Check propname before applying "cs-gpios" quirks
        gpio: mockup: fix debugfs read
        Revert "gpio: use new gpio_set_config() helper in more places"
        gpio: aspeed: fix a potential NULL pointer dereference
        gpio: amd-fch: Fix bogus SPDX identifier
        gpio: adnp: Fix testing wrong value in adnp_gpio_direction_input
        gpio: exar: add a check for the return value of ida_simple_get fails
      3af9a525
    • Rasmus Villemoes's avatar
      leds: trigger: netdev: use memcpy in device_name_store · 90934643
      Rasmus Villemoes authored
      If userspace doesn't end the input with a newline (which can easily
      happen if the write happens from a C program that does write(fd,
      iface, strlen(iface))), we may end up including garbage from a
      previous, longer value in the device_name. For example
      
      # cat device_name
      
      # printf 'eth12' > device_name
      # cat device_name
      eth12
      # printf 'eth3' > device_name
      # cat device_name
      eth32
      
      I highly doubt anybody is relying on this behaviour, so switch to
      simply copying the bytes (we've already checked that size is <
      IFNAMSIZ) and unconditionally zero-terminate it; of course, we also
      still have to strip a trailing newline.
      
      This is also preparation for future patches.
      
      Fixes: 06f502f5 ("leds: trigger: Introduce a NETDEV trigger")
      Signed-off-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
      Acked-by: default avatarPavel Machek <pavel@ucw.cz>
      Signed-off-by: default avatarJacek Anaszewski <jacek.anaszewski@gmail.com>
      90934643