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>
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 4f53b8e..cea7a8a 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -120,7 +120,13 @@
* ---------------------------------------------------------------------
*/
.macro handle_interrupt_exception label
+
bl save_gp_registers
+
+#if CTX_INCLUDE_PAUTH_REGS
+ bl pauth_context_save
+#endif
+
/* Save the EL3 system registers needed to return from this exception */
mrs x0, spsr_el3
mrs x1, elr_el3
@@ -320,14 +326,21 @@
tbnz x0, #FUNCID_CC_SHIFT, smc_prohibited
smc_handler64:
+ /* NOTE: The code below must preserve x0-x4 */
+
+ /* Save general purpose registers */
+ bl save_gp_registers
+
+#if CTX_INCLUDE_PAUTH_REGS
+ bl pauth_context_save
+#endif
+
/*
* Populate the parameters for the SMC handler.
* We already have x0-x4 in place. x5 will point to a cookie (not used
* now). x6 will point to the context structure (SP_EL3) and x7 will
* contain flags we need to pass to the handler.
*/
- bl save_gp_registers
-
mov x5, xzr
mov x6, sp