1. 14 Nov, 2014 37 commits
  2. 30 Oct, 2014 3 commits
    • Greg Kroah-Hartman's avatar
      Linux 3.17.2 · 906d77a3
      Greg Kroah-Hartman authored
      906d77a3
    • David S. Miller's avatar
      sparc64: Implement __get_user_pages_fast(). · 29e74317
      David S. Miller authored
      [ Upstream commit 06090e8e ]
      
      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>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      29e74317
    • David S. Miller's avatar
      sparc64: Fix register corruption in top-most kernel stack frame during boot. · 3ecc3b82
      David S. Miller authored
      [ Upstream commit ef3e035c ]
      
      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-gd7933ab7 #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>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3ecc3b82