Hello,

in an attempt to familiarize myself with the seL4 code, I am trying to "port" it to the Wandboard (see www.wandboard.org). This should be an easy task for a beginner (thought I) since the board is very similar to the SabeLite, and seL4 is already running well on that board. I have access to a SabreLite and a Wandboard Quad, both (according to U-boot) have the same revision of the iMX6 SoC installed.

Differences between the Sabre and the Wand I have noticed so far are:

- 2GB of RAM from (0x10000000 to 0x90000000) on the Wand (Sabrelite has 1GB) - Wand uses UART1 for debug output, Sabrelite: UART2

I compiled an sel4test project where I adapted the UART port in kernel/include/plat/imx6/plat/machine/devices.h and elfloader/src/arch-arm/plat-imx6/platform.h and the RAM size in kernel src/plat/imx6/machine/hardware.c. When I boot this system, I get:

Jumping to kernel-image entry point... Bootstrapping kernel Caught cap fault in send phase at address 0x0 while trying to handle: vm fault on data at address 0x9f11c2e0 with status 0x1c06 in thread 0xffdfad00 at address 0x13294

(Needless to say, "all is well in the universe" on the SabreLite... ) What is not shown here are a ton of other debug messages which I have added to convince myself that kernel initialization completes as expected. The crash seems to happen upon entry into user code. The address 0x13294 is the virtual address of the entry point:

$ nm build/arm/imx6/sel4test-driver/sel4test-driver.bin | grep 13294 00013294 T _sel4_start

I suspect that this fault happens on opcode fetch, because the user code is not properly mapped when invoked. Does "status 0x1c06" confirm this?

If so, *should* the code be mapped at this point or are these mappings expected to be installed "on demand", i.e. through page fault handling?

Thanks for any help...

Robert