2018-02-27 18:11 GMT+01:00 Mark Rutland <mark.rutland@xxxxxxx>: > On Tue, Feb 27, 2018 at 03:09:23PM +0100, Benjamin Gaignard wrote: >> On early boot stages STM32MP1 platform is able to dedicate some hardware blocks >> to a secure OS running in TrustZone. >> We need to avoid using those hardware blocks on non-secure context (i.e. kernel) >> because read/write access will all be discarded. >> >> Extended TrustZone Protection driver register itself as listener of >> BUS_NOTIFY_BIND_DRIVER and check, given the device address, if the hardware block >> could be used in a Linux context. If not it returns NOTIFY_BAD to driver core >> to stop driver probing. > > Huh? > > If these devices are not usable from the non-secure side, why are they > not removed form the DT (or marked disabled)? > > In other cases, where resources are carved out for the secure side (e.g. > DRAM carveouts), that's how we handle things. > That true you can parse and disable a device a boot time but if DT doesn't exactly reflect etzpc status bits we will in trouble when try to get access to the device. Changing the DT is a software protection while etzpc is an hardware protection so we need to check it anyway. Benjamin > Mark. > >> >> NOTE: patches 2 and 3 should be applied only on >> git://git.kernel.org/pub/scm/linux/kernel/git/atorgue/stm32.git stm32-next >> but until this patch: https://lkml.org/lkml/2018/2/26/386 >> find it way to mailine KBuild will complain about them. >> >> Benjamin Gaignard (3): >> driver core: check notifier_call_chain return value >> dt-bindings: stm32: Add bindings for Extended TrustZone Protection >> ARM: mach-stm32: Add Extended TrustZone Protection driver >> >> .../bindings/arm/stm32/st,stm32mp1-etzpc.txt | 13 ++ >> arch/arm/mach-stm32/Kconfig | 7 + >> arch/arm/mach-stm32/Makefile | 1 + >> arch/arm/mach-stm32/stm32-etzpc.c | 252 +++++++++++++++++++++ >> drivers/base/dd.c | 9 +- >> 5 files changed, 279 insertions(+), 3 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/arm/stm32/st,stm32mp1-etzpc.txt >> create mode 100644 arch/arm/mach-stm32/stm32-etzpc.c >> >> -- >> 2.15.0 >> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
