1. 27 Mar, 2017 3 commits
    • Guilherme G. Piccoli's avatar
      powerpc/xmon: add debugfs entry for xmon · de78ae6c
      Guilherme G. Piccoli authored
      Currently the xmon debugger is set only via kernel boot command-line.
      It's disabled by default, and can be enabled with "xmon=on" on the
      command-line. Also, xmon may be accessed via sysrq mechanism.
      But we cannot enable/disable xmon in runtime, it needs kernel reload.
      
      This patch introduces a debugfs entry for xmon, allowing user to query
      its current state and change it if desired. Basically, the "xmon" file
      to read from/write to is under the debugfs mount point, on powerpc
      directory. It's a simple attribute, value 0 meaning xmon is disabled
      and value 1 the opposite. Writing these states to the file will take
      immediate effect in the debugger.
      Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      de78ae6c
    • Guilherme G. Piccoli's avatar
      powerpc/xmon: drop the nobt option from xmon plus minor fixes · b561783c
      Guilherme G. Piccoli authored
      The xmon parameter nobt was added long time ago, by commit 26c8af5f
      ("[POWERPC] print backtrace when entering xmon"). The problem that time
      was that during a crash in a machine with USB keyboard, xmon wouldn't
      respond to commands from the keyboard, so printing the backtrace wouldn't
      be possible.
      
      Idea then was to show automatically the backtrace on xmon crash for the
      first time it's invoked (if it recovers, next time xmon won't show
      backtrace automatically). The nobt parameter was added _only_ to prevent
      this automatic trace show. Seems long time ago USB keyboards didn't work
      that well!
      
      We don't need this parameter anymore, the feature of auto showing the
      backtrace is interesting (imagine a case of auto-reboot script),
      so this patch extends the functionality, by always showing the backtrace
      automatically when xmon is invoked; it removes the nobt parameter too.
      
      Also, this patch fixes __initdata placement on xmon_early and replaces
      __initcall() with modern device_initcall() on sysrq handler.
      Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      b561783c
    • Pan Xinhui's avatar
      powerpc/xmon: Fix an unexpected xmon on/off state change · 3b5bf42b
      Pan Xinhui authored
      Once xmon is triggered by sysrq-x, it is enabled always afterwards even
      if it is disabled during boot. This will cause a system reset interrupt
      fail to dump. So keep xmon in its original state after exit.
      
      We have several ways to set xmon on or off.
      1) by a build config CONFIG_XMON_DEFAULT.
      2) by a boot cmdline with xmon or xmon=early or xmon=on to enable xmon
      and xmon=off to disable xmon. This value will override that in step 1.
      3) by a debugfs interface, as proposed in this patchset.
      And this value can override those in step 1 and 2.
      Signed-off-by: default avatarPan Xinhui <xinhui.pan@linux.vnet.ibm.com>
      Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      3b5bf42b
  2. 21 Mar, 2017 13 commits
  3. 20 Mar, 2017 14 commits
  4. 19 Mar, 2017 10 commits