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>

4 files changed, 35 insertions, 2 deletions

diff --git a/include/arch/aarch32/arch.h b/include/arch/aarch32/arch.h
index 5b160a227..7221b6273 100644
--- a/include/arch/aarch32/arch.h
+++ b/include/arch/aarch32/arch.h
@@ -107,6 +107,10 @@
 #define ID_DFR0_COPTRC_MASK		U(0xf)
 #define ID_DFR0_COPTRC_SUPPORTED	U(1)
 #define ID_DFR0_COPTRC_LENGTH		U(4)
+#define ID_DFR0_TRACEFILT_SHIFT		U(28)
+#define ID_DFR0_TRACEFILT_MASK		U(0xf)
+#define ID_DFR0_TRACEFILT_SUPPORTED	U(1)
+#define ID_DFR0_TRACEFILT_LENGTH	U(4)
 
 /* ID_DFR1_EL1 definitions */
 #define ID_DFR1_MTPMU_SHIFT	U(0)
@@ -179,6 +183,7 @@
 #define SDCR_SPD_DISABLE	U(0x2)
 #define SDCR_SPD_ENABLE		U(0x3)
 #define SDCR_SCCD_BIT		(U(1) << 23)
+#define SDCR_TTRF_BIT		(U(1) << 19)
 #define SDCR_SPME_BIT		(U(1) << 17)
 #define SDCR_RESET_VAL		U(0x0)
 #define SDCR_MTPME_BIT		(U(1) << 28)
diff --git a/include/arch/aarch32/el3_common_macros.S b/include/arch/aarch32/el3_common_macros.S
index 49e8518d3..65f9a8e6b 100644
--- a/include/arch/aarch32/el3_common_macros.S
+++ b/include/arch/aarch32/el3_common_macros.S
@@ -131,9 +131,22 @@
 	 *  in Secure state. This bit is RES0 in versions of the architecture
 	 *  earlier than ARMv8.5, setting it to 1 doesn't have any effect on
 	 *  them.
+	 *
+	 * SDCR.TTRF: Set to one so that access to trace filter control
+	 *  registers in non-monitor mode generate Monitor 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.
 	 * ---------------------------------------------------------------------
 	 */
-	ldr	r0, =(SDCR_RESET_VAL | SDCR_SPD(SDCR_SPD_DISABLE) | SDCR_SCCD_BIT)
+	ldr	r0, =((SDCR_RESET_VAL | SDCR_SPD(SDCR_SPD_DISABLE) | \
+		      SDCR_SCCD_BIT) & ~SDCR_TTRF_BIT)
+	ldcopr	r1, ID_DFR0
+	ubfx	r1, r1, #ID_DFR0_TRACEFILT_SHIFT, #ID_DFR0_TRACEFILT_LENGTH
+	cmp	r1, #ID_DFR0_TRACEFILT_SUPPORTED
+	bne	1f
+	orr	r0, r0, #SDCR_TTRF_BIT
+1:
 	stcopr	r0, SDCR
 
 	/* ---------------------------------------------------------------------
diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index 2a3812394..9ea111452 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -193,6 +193,10 @@
 #define ID_AA64DFR0_TRACEVER_MASK	ULL(0xf)
 #define ID_AA64DFR0_TRACEVER_SUPPORTED	ULL(1)
 #define ID_AA64DFR0_TRACEVER_LENGTH	U(4)
+#define ID_AA64DFR0_TRACEFILT_SHIFT	U(40)
+#define ID_AA64DFR0_TRACEFILT_MASK	U(0xf)
+#define ID_AA64DFR0_TRACEFILT_SUPPORTED	U(1)
+#define ID_AA64DFR0_TRACEFILT_LENGTH	U(4)
 
 /* ID_AA64DFR0_EL1.PMS definitions (for ARMv8.2+) */
 #define ID_AA64DFR0_PMS_SHIFT	U(32)
diff --git a/include/arch/aarch64/el3_common_macros.S b/include/arch/aarch64/el3_common_macros.S
index 18fe0de1e..d4965841f 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
 
 	/* ---------------------------------------------------------------------