feat(trf): initialize trap settings of trace filter control registers access
Trap bits of trace filter control registers access are in
architecturally UNKNOWN state at boot hence
1. Initialized trap bits to one to prohibit trace filter control
registers accesses in lower ELs (EL2, EL1) in all security states
when FEAT_TRF is implemented.
2. These bits are RES0 when FEAT_TRF is not implemented and hence set
it to zero to aligns with the Arm ARM reference recommendation,
that mentions software must writes RES0 bits with all 0s.
Change-Id: I1b7abf2170ece84ee585c91cda32d22b25c0fc34
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/include/arch/aarch64/el3_common_macros.S b/include/arch/aarch64/el3_common_macros.S
index 18fe0de..d496584 100644
--- a/include/arch/aarch64/el3_common_macros.S
+++ b/include/arch/aarch64/el3_common_macros.S
@@ -132,14 +132,25 @@
* accesses to Trace Buffer control registers at EL2 and EL1 in any
* security state generates trap exceptions to EL3.
* If FEAT_TRBE is not implemented, these bits are RES0.
+ *
+ * MDCR_EL3.TTRF: Set to one so that access to trace filter control
+ * registers in non-monitor mode generate EL3 trap exception,
+ * unless the access generates a higher priority exception when trace
+ * filter control(FEAT_TRF) is implemented.
+ * When FEAT_TRF is not implemented, this bit is RES0.
* ---------------------------------------------------------------------
*/
mov_imm x0, ((MDCR_EL3_RESET_VAL | MDCR_SDD_BIT | \
MDCR_SPD32(MDCR_SPD32_DISABLE) | MDCR_SCCD_BIT | \
MDCR_MCCD_BIT) & ~(MDCR_SPME_BIT | MDCR_TDOSA_BIT | \
MDCR_TDA_BIT | MDCR_TPM_BIT | MDCR_NSTB(MDCR_NSTB_EL1) | \
- MDCR_NSTBE))
+ MDCR_NSTBE | MDCR_TTRF_BIT))
+ mrs x1, id_aa64dfr0_el1
+ ubfx x1, x1, #ID_AA64DFR0_TRACEFILT_SHIFT, #ID_AA64DFR0_TRACEFILT_LENGTH
+ cbz x1, 1f
+ orr x0, x0, #MDCR_TTRF_BIT
+1:
msr mdcr_el3, x0
/* ---------------------------------------------------------------------