On 16/11/17 22:41 Marc Zyngier [mailto:marc.zyng...@arm.com] wrote: >No, it doesn't. It cannot work, because Cortex-A9 predates the invention >of the 64bit accessor. I suspect that you are testing stuff in QEMU, >which is giving you a SW model that always supports LPAE. I suggest you >test this code on *real* HW, and not only on QEMU.
I am sorry. My test is fault. I only defined TTBR0 as __ACCESS_CP15_64, but I don't use the definition TTBR0 as __ACCESS_CP15_64. Now I use the definition TTBR0 as __ACCESS_CP15_64 on CPU supporting LPAE(vexpress_a9), I find it doesn't work and report undefined instruction error when execute "mrrc" instruction. So, you are right that 64bit accessor of TTBR0 cannot work on LPAE.
