In the S-EL1&0 translation regime we aren't using the higher VA range,
whose translation table base address is held in TTBR1_EL1. The bit
TCR_EL1.EPD1 can be used to disable translations using TTBR1_EL1, but
the code wasn't setting it to 1. Additionally, other fields in TCR1_EL1
associated with the higher VA range (TBI1, TG1, SH1, ORGN1, IRGN1 and
A1) weren't set correctly as they were left as 0. In particular, 0 is a
reserved value for TG1. Also, TBBR1_EL1 was not explicitly set and its
reset value is UNKNOWN.
Therefore memory accesses to the higher VA range would result in
unpredictable behaviour as a translation table walk would be attempted
using an UNKNOWN value in TTBR1_EL1.
On the FVP and Juno platforms accessing the higher VA range resulted in
a translation fault, but this may not always be the case on all
platforms.
This patch sets the bit TCR_EL1.EPD1 to 1 so that any kind of
unpredictable behaviour is prevented.
This bug only affects the AArch64 version of the code, the AArch32
version sets this bit to 1 as expected.
Change-Id: I481c000deda5bc33a475631301767b9e0474a303
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
3388b38dc3