During boot, we take the debug OS lock before interrupts are enabled.
This is required to prevent clearing of PSTATE.D on the interrupt entry
path, which could result in spurious debug exceptions before we've got
round to resetting things like the hardware breakpoints registers to a
sane state.
A problem with this approach is that taking the OS lock prevents an
external JTAG debugger from debugging the system, which is especially
irritating during boot, where JTAG debugging can be most useful.
This patch clears mdscr_el1 rather than taking the lock, clearing the
MDE and KDE bits and preventing self-hosted hardware debug exceptions
from occurring.
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: stable@vger.kernel.org
If such bit exists on a given CPU, it must be set by the firmware or
boot-loader prior to starting the kernel (see
Documentation/arm64/booting.txt).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch adds AArch64 CPU specific functionality. It assumes that the
implementation is generic to AArch64 and does not require specific
identification. Different CPU implementations may require the setting of
various ACTLR_EL1 bits but such information is not currently available
and it should ideally be pushed to firmware.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Will Deacon
Catalin Marinas