From: Jean-Philippe Brucker jean-philippe.brucker@arm.com
commit 6fda41bf12615ee7c3ddac88155099b1a8cf8d00 upstream.
Some firmwares may reboot CPUs with OS Double Lock set. Make sure that it is unlocked, in order to use debug exceptions.
Cc: stable@vger.kernel.org Signed-off-by: Jean-Philippe Brucker jean-philippe.brucker@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/kernel/debug-monitors.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -133,6 +133,7 @@ NOKPROBE_SYMBOL(disable_debug_monitors); */ static int clear_os_lock(unsigned int cpu) { + write_sysreg(0, osdlr_el1); write_sysreg(0, oslar_el1); isb(); return 0;