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  1. Nov 20, 2014
  2. Nov 18, 2014
    • Yann Droneaud's avatar
      arm64/mm: Remove hack in mmap randomize layout · d6c763af
      Yann Droneaud authored
      
      
      Since commit 8a0a9bd4 ('random: make get_random_int() more
      random'), get_random_int() returns a random value for each call,
      so comment and hack introduced in mmap_rnd() as part of commit
      1d18c47c ('arm64: MMU fault handling and page table management')
      are incorrects.
      
      Commit 1d18c47c seems to use the same hack introduced by
      commit a5adc91a ('powerpc: Ensure random space between stack
      and mmaps'), latter copied in commit 5a0efea0 ('sparc64: Sharpen
      address space randomization calculations.').
      
      But both architectures were cleaned up as part of commit
      fa8cbaaf ('powerpc+sparc64/mm: Remove hack in mmap randomize
      layout') as hack is no more needed since commit 8a0a9bd4.
      
      So the present patch removes the comment and the hack around
      get_random_int() on AArch64's mmap_rnd().
      
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Anton Blanchard <anton@samba.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Acked-by: default avatarWill Deacon <will.deacon@arm.com>
      Acked-by: default avatarDan McGee <dpmcgee@gmail.com>
      Signed-off-by: default avatarYann Droneaud <ydroneaud@opteya.com>
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      d6c763af
  3. Nov 17, 2014
    • Catalin Marinas's avatar
      arm64: Add COMPAT_HWCAP_LPAE · 7d57511d
      Catalin Marinas authored
      
      
      Commit a469abd0 (ARM: elf: add new hwcap for identifying atomic
      ldrd/strd instructions) introduces HWCAP_ELF for 32-bit ARM
      applications. As LPAE is always present on arm64, report the
      corresponding compat HWCAP to user space.
      
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      Cc: <stable@vger.kernel.org> # 3.11+
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      7d57511d
    • Will Deacon's avatar
      mmu_gather: move minimal range calculations into generic code · fb7332a9
      Will Deacon authored
      
      
      On architectures with hardware broadcasting of TLB invalidation messages
      , it makes sense to reduce the range of the mmu_gather structure when
      unmapping page ranges based on the dirty address information passed to
      tlb_remove_tlb_entry.
      
      arm64 already does this by directly manipulating the start/end fields
      of the gather structure, but this confuses the generic code which
      does not expect these fields to change and can end up calculating
      invalid, negative ranges when forcing a flush in zap_pte_range.
      
      This patch moves the minimal range calculation out of the arm64 code
      and into the generic implementation, simplifying zap_pte_range in the
      process (which no longer needs to care about start/end, since they will
      point to the appropriate ranges already). With the range being tracked
      by core code, the need_flush flag is dropped in favour of checking that
      the end of the range has actually been set.
      
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
      Cc: Michal Simek <monstr@monstr.eu>
      Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      fb7332a9
  4. Nov 14, 2014
    • Will Deacon's avatar
      arm64: entry: use ldp/stp instead of push/pop when saving/restoring regs · 63648dd2
      Will Deacon authored
      
      
      The push/pop instructions can be suboptimal when saving/restoring large
      amounts of data to/from the stack, for example on entry/exit from the
      kernel. This is because:
      
        (1) They act on descending addresses (i.e. the newly decremented sp),
            which may defeat some hardware prefetchers
      
        (2) They introduce an implicit dependency between each instruction, as
            the sp has to be updated in order to resolve the address of the
            next access.
      
      This patch removes the push/pop instructions from our kernel entry/exit
      macros in favour of ldp/stp plus offset.
      
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      63648dd2
    • Will Deacon's avatar
      arm64: entry: avoid writing lr explicitly for constructing return paths · d54e81f9
      Will Deacon authored
      
      
      Using an explicit adr instruction to set the link register to point at
      ret_fast_syscall/ret_to_user can defeat branch and return stack predictors.
      
      Instead, use the standard calling instructions (bl, blr) and have an
      unconditional branch as the following instruction.
      
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      d54e81f9
    • Mark Rutland's avatar
      arm64: Fix up /proc/cpuinfo · 44b82b77
      Mark Rutland authored
      Commit d7a49086f263164a (arm64: cpuinfo: print info for all CPUs)
      attempted to clean up /proc/cpuinfo, but due to concerns regarding
      further changes was reverted in commit 5e39977edf6500fd (Revert "arm64:
      cpuinfo: print info for all CPUs").
      
      There are two major issues with the arm64 /proc/cpuinfo format
      currently:
      
      * The "Features" line describes (only) the 64-bit hwcaps, which is
        problematic for some 32-bit applications which attempt to parse it. As
        the same names are used for analogous ISA features (e.g. aes) despite
        these generally being architecturally unrelated, it is not possible to
        simply append the 64-bit and 32-bit hwcaps in a manner that might not
        be misleading to some applications.
      
        Various potential solutions have appeared in vendor kernels. Typically
        the format of the Features line varies depending on whether the task
        is 32-bit.
      
      * Information is only printed regarding a single CPU. This does not
        match the ARM format, and does not provide sufficient information in
        big.LITTLE systems where CPUs are heterogeneous. The CPU information
        printed is queried from the current CPU's registers, which is racy
        w.r.t. cross-cpu migration.
      
      This patch attempts to solve these issues. The following changes are
      made:
      
      * When a task with a LINUX32 personality attempts to read /proc/cpuinfo,
        the "Features" line contains the decoded 32-bit hwcaps, as with the
        arm port. Otherwise, the decoded 64-bit hwcaps are shown. This aligns
        with the behaviour of COMPAT_UTS_MACHINE and COMPAT_ELF_PLATFORM. In
        the absense of compat support, the Features line is empty.
      
        The set of hwcaps injected into a task's auxval are unaffected.
      
      * Properties are printed per-cpu, as with the ARM port. The per-cpu
        information is queried from pre-recorded cpu information (as used by
        the sanity checks).
      
      * As with the previous attempt at fixing up /proc/cpuinfo, the hardware
        field is removed. The only users so far are 32-bit applications tied
        to particular boards, so no portable applications should be affected,
        and this should prevent future tying to particular boards.
      
      The following differences remain:
      
      * No model_name is printed, as this cannot be queried from the hardware
        and cannot be provided in a stable fashion. Use of the CPU
        {implementor,variant,part,revision} fields is sufficient to identify a
        CPU and is portable across arm and arm64.
      
      * The following system-wide properties are not provided, as they are not
        possible to provide generally. Programs relying on these are already
        tied to particular (32-bit only) boards:
        - Hardware
        - Revision
        - Serial
      
      No software has yet been identified for which these remaining
      differences are problematic.
      
      Cc: Greg Hackmann <ghackmann@google.com>
      Cc: Ian Campbell <ijc@hellion.org.uk>
      Cc: Serban Constantinescu <serban.constantinescu@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: cross-distro@lists.linaro.org
      Cc: linux-api@vger.kernel.org
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: linux-kernel@vger.kernel.org
      Acked-by: Catalin Marinas <catalin.marinas@arm.com>
      Signed-off-by: Mark Rutland <mark.rutland@arm.com>
      Signed-off-by: Will Deacon <will.deacon@arm.com>
      44b82b77
  5. Nov 07, 2014
  6. Nov 06, 2014
  7. Nov 05, 2014
  8. Oct 25, 2014
  9. Oct 24, 2014
    • Catalin Marinas's avatar
      arm64: Fix memblock current_limit with 64K pages and 48-bit VA · 3dec0fe4
      Catalin Marinas authored
      
      
      With 48-bit VA space, the 64K page configuration uses 3 levels instead
      of 2 and PUD_SIZE != PMD_SIZE. Since with 64K pages we only cover
      PMD_SIZE with the initial swapper_pg_dir populated in head.S, the
      memblock current_limit needs to be set accordingly in map_mem() to avoid
      allocating unmapped memory. The memblock current_limit is progressively
      increased as more blocks are mapped.
      
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      3dec0fe4
    • David S. Miller's avatar
      sparc64: Implement __get_user_pages_fast(). · 06090e8e
      David S. Miller authored
      
      
      It is not sufficient to only implement get_user_pages_fast(), you
      must also implement the atomic version __get_user_pages_fast()
      otherwise you end up using the weak symbol fallback implementation
      which simply returns zero.
      
      This is dangerous, because it causes the futex code to loop forever
      if transparent hugepages are supported (see get_futex_key()).
      
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      06090e8e
    • David S. Miller's avatar
      sparc64: Fix register corruption in top-most kernel stack frame during boot. · ef3e035c
      David S. Miller authored
      
      
      Meelis Roos reported that kernels built with gcc-4.9 do not boot, we
      eventually narrowed this down to only impacting machines using
      UltraSPARC-III and derivitive cpus.
      
      The crash happens right when the first user process is spawned:
      
      [   54.451346] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
      [   54.451346]
      [   54.571516] CPU: 1 PID: 1 Comm: init Not tainted 3.16.0-rc2-00211-gd7933ab #96
      [   54.666431] Call Trace:
      [   54.698453]  [0000000000762f8c] panic+0xb0/0x224
      [   54.759071]  [000000000045cf68] do_exit+0x948/0x960
      [   54.823123]  [000000000042cbc0] fault_in_user_windows+0xe0/0x100
      [   54.902036]  [0000000000404ad0] __handle_user_windows+0x0/0x10
      [   54.978662] Press Stop-A (L1-A) to return to the boot prom
      [   55.050713] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
      
      Further investigation showed that compiling only per_cpu_patch() with
      an older compiler fixes the boot.
      
      Detailed analysis showed that the function is not being miscompiled by
      gcc-4.9, but it is using a different register allocation ordering.
      
      With the gcc-4.9 compiled function, something during the code patching
      causes some of the %i* input registers to get corrupted.  Perhaps
      we have a TLB miss path into the firmware that is deep enough to
      cause a register window spill and subsequent restore when we get
      back from the TLB miss trap.
      
      Let's plug this up by doing two things:
      
      1) Stop using the firmware stack for client interface calls into
         the firmware.  Just use the kernel's stack.
      
      2) As soon as we can, call into a new function "start_early_boot()"
         to put a one-register-window buffer between the firmware's
         deepest stack frame and the top-most initial kernel one.
      
      Reported-by: default avatarMeelis Roos <mroos@linux.ee>
      Tested-by: default avatarMeelis Roos <mroos@linux.ee>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ef3e035c
    • Arun Chandran's avatar
      arm64: ASLR: Don't randomise text when randomise_va_space == 0 · 92980405
      Arun Chandran authored
      
      
      When user asks to turn off ASLR by writing "0" to
      /proc/sys/kernel/randomize_va_space there should not be
      any randomization to mmap base, stack, VDSO, libs, text and heap
      
      Currently arm64 violates this behavior by randomising text.
      Fix this by defining a constant ELF_ET_DYN_BASE. The randomisation of
      mm->mmap_base is done by setup_new_exec -> arch_pick_mmap_layout ->
      mmap_base -> mmap_rnd.
      
      Signed-off-by: default avatarArun Chandran <achandran@mvista.com>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      92980405
    • Ralf Baechle's avatar
      MIPS: SEAD3: Fix I2C device registration. · 4846f118
      Ralf Baechle authored
      
      
      This isn't a module and shouldn't be one.
      
      Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      4846f118
    • Nadav Amit's avatar
      KVM: x86: Wrong assertion on paging_tmpl.h · 1715d0dc
      Nadav Amit authored
      
      
      Even after the recent fix, the assertion on paging_tmpl.h is triggered.
      Apparently, the assertion wants to check that the PAE is always set on
      long-mode, but does it in incorrect way.  Note that the assertion is not
      enabled unless the code is debugged by defining MMU_DEBUG.
      
      Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      1715d0dc
    • Nadav Amit's avatar
      KVM: x86: PREFETCH and HINT_NOP should have SrcMem flag · 3f6f1480
      Nadav Amit authored
      
      
      The decode phase of the x86 emulator assumes that every instruction with the
      ModRM flag, and which can be used with RIP-relative addressing, has either
      SrcMem or DstMem.  This is not the case for several instructions - prefetch,
      hint-nop and clflush.
      
      Adding SrcMem|NoAccess for prefetch and hint-nop and SrcMem for clflush.
      
      This fixes CVE-2014-8480.
      
      Fixes: 41061cdb
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      3f6f1480
    • Nadav Amit's avatar
      KVM: x86: Emulator does not decode clflush well · 13e457e0
      Nadav Amit authored
      
      
      Currently, all group15 instructions are decoded as clflush (e.g., mfence,
      xsave).  In addition, the clflush instruction requires no prefix (66/f2/f3)
      would exist. If prefix exists it may encode a different instruction (e.g.,
      clflushopt).
      
      Creating a group for clflush, and different group for each prefix.
      
      This has been the case forever, but the next patch needs the cflush group
      in order to fix a bug introduced in 3.17.
      
      Fixes: 41061cdb
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      13e457e0
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