From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Wed, 25 Feb 2015 11:38:39 -0700 Subject: [U-Boot] u-boot on raspberry 2: booting in SVC secure mode In-Reply-To: References: Message-ID: <54EE16AF.9070304@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 02/25/2015 02:30 AM, Vincent wrote: > Hi, > as explained here http://community.arm.com/message/25127, it is possible to > boot the raspberry 2 in secure mode, by adding the kernel_old=1 option in > config.txt. The main effects of this option are: > - all 4 cores start executing in secure SVC mode instead of non-secure SVC > mode > - all 4 cores start at 0x0000 instead of 0x8000 > - the initial boot code that setup SMP and exits secure mode is not > executed > > After browsing u-boot's source code, it seems that their boot code is more > or less extracted from what u-boot is doing. However I didn't manage to > compile u-boot for the raspberry 2 supporting this secure mode. > > Could anyone explain me what options I need to configure in rpi_2_defconfig > so that u-boot supports secure boot for the raspberry 2 and what the boot > sequence will be in this case ? I don't mind fixing the code if necessary > but I'm a bit lost in the order of events in the initialization. (Luckily I just happened to notice this message while looking at another one nearby. CCing the relevant board maintainer(s) explicitly would help your messages be noticed) To modify U-Boot to support the alternate entry point/load address, you'd hopefully only need to change the definition of CONFIG_SYS_TEXT_BASE in include/configs/rpi*.h. I wasn't aware of the thread/option you mention, so I have not attempted to boot the RPi2 U-Boot in secure mode. If you're lucky, U-Boot itself will "just work" once TEXT_BASE is fixed. To boot a kernel, you'll probably need to at least configure the ARM architected timers CNTFRQ register for the kernel. Perhaps there are a few other things like that missing? It might be interesting to enable U-Boot's PSCI support on the RPi2, so that an upstream kernel could gain SMP support without the need for explicit BCM2836 SMP support code. So far, I haven't attempted anything with an (upstream) kernel on RPi2, just U-Boot.