releases/4.19.45/arm64-clear-osdlr_el1-on-cpu-boot.patch

   1 From 6fda41bf12615ee7c3ddac88155099b1a8cf8d00 Mon Sep 17 00:00:00 2001
   2 From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
   3 Date: Mon, 8 Apr 2019 18:17:18 +0100
   4 Subject: arm64: Clear OSDLR_EL1 on CPU boot
   5
   6 From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
   7
   8 commit 6fda41bf12615ee7c3ddac88155099b1a8cf8d00 upstream.
   9
  10 Some firmwares may reboot CPUs with OS Double Lock set. Make sure that
  11 it is unlocked, in order to use debug exceptions.
  12
  13 Cc: <stable@vger.kernel.org>
  14 Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
  15 Signed-off-by: Will Deacon <will.deacon@arm.com>
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  17
  18 ---
  19  arch/arm64/kernel/debug-monitors.c |    1 +
  20  1 file changed, 1 insertion(+)
  21
  22 --- a/arch/arm64/kernel/debug-monitors.c
  23 +++ b/arch/arm64/kernel/debug-monitors.c
  24 @@ -135,6 +135,7 @@ NOKPROBE_SYMBOL(disable_debug_monitors);
  25   */
  26  static int clear_os_lock(unsigned int cpu)
  27  {
  28 +       write_sysreg(0, osdlr_el1);
  29         write_sysreg(0, oslar_el1);
  30         isb();
  31         return 0;