path: root/docs/firmware-design.rst
diff options
authorAntonio Nino Diaz <antonio.ninodiaz@arm.com>2019-01-31 11:58:00 +0000
committerAntonio Nino Diaz <antonio.ninodiaz@arm.com>2019-02-27 11:08:59 +0000
commit5283962ebaf77850d68bb457608ede5174e43159 (patch)
tree28fbac607b59b0d21cdef870f74afa5a78f274d9 /docs/firmware-design.rst
parent4d1ccf0ecc7d90df438148c633291723d095f979 (diff)
Add ARMv8.3-PAuth registers to CPU context
ARMv8.3-PAuth adds functionality that supports address authentication of the contents of a register before that register is used as the target of an indirect branch, or as a load. This feature is supported only in AArch64 state. This feature is mandatory in ARMv8.3 implementations. This feature adds several registers to EL1. A new option called CTX_INCLUDE_PAUTH_REGS has been added to select if the TF needs to save them during Non-secure <-> Secure world switches. This option must be enabled if the hardware has the registers or the values will be leaked during world switches. To prevent leaks, this patch also disables pointer authentication in the Secure world if CTX_INCLUDE_PAUTH_REGS is 0. Any attempt to use it will be trapped in EL3. Change-Id: I27beba9907b9a86c6df1d0c5bf6180c972830855 Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Diffstat (limited to 'docs/firmware-design.rst')
1 files changed, 7 insertions, 2 deletions
diff --git a/docs/firmware-design.rst b/docs/firmware-design.rst
index 299654fc26..808afeedb9 100644
--- a/docs/firmware-design.rst
+++ b/docs/firmware-design.rst
@@ -2558,8 +2558,13 @@ Armv8.2-A
-- Pointer Authentication features of Armv8.3-A are unconditionally enabled so
- that lower ELs are allowed to use them without causing a trap to EL3.
+- Pointer authentication features of Armv8.3-A are unconditionally enabled in
+ the Non-secure world so that lower ELs are allowed to use them without
+ causing a trap to EL3.
+ In order to enable the Secure world to use it, ``CTX_INCLUDE_PAUTH_REGS``
+ must be set to 1. This will add all pointer authentication system registers
+ to the context that is saved when doing a world switch.