On 2 August 2016 at 18:15, Cédric Le Goater <c...@kaod.org> wrote: > On the AST2500, I am still having a little issue under uboot which > sets the vbar doing : > > mcr p15, 0, r0, c12, c0, 0 /* Set VBAR */ > > and this is trapped as an undefined instruction by qemu. > > Looking at hw/arm/helper.c, the VBAR register seems to be defined > only for feature ARM_FEATURE_V7 (v7_cp_reginfo). The AST2500 SoC > uses a arm1176 which defines ARM_FEATURE_EL3 which gives us a > VBAR_EL3. According to th specs, the arm1176jzf-s has a Vector > Base Address Register. So am I missing something in the board > definition or is uboot being too optimistic on the cpu features ? > This is confusing for me, some direction would be welcomed :)
This looks like a bug in helper.c -- we originally added the VBAR definition as a bit of a hack since it's only supposed to exist in CPUs with the security extensions and at the time we didn't implement those at all. It should definitely exist in the 1176 too, so we should move the definition around somewhere so it does. (The 1176 is the only non-v7 CPU with security extensions support, which is why it got missed I suspect.) thanks -- PMM
