Merge pull request #997 from dp-arm/dp/spe

aarch64: Enable Statistical Profiling Extensions for lower ELs

2 files changed, 62 insertions, 4 deletions

diff --git a/lib/el3_runtime/aarch64/context.S b/lib/el3_runtime/aarch64/context.S
index afe912ab..8a6c11b7 100644
--- a/lib/el3_runtime/aarch64/context.S
+++ b/lib/el3_runtime/aarch64/context.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,7 @@
 #include <context.h>
 
 	.global	el1_sysregs_context_save
+	.global el1_sysregs_context_save_post_ops
 	.global	el1_sysregs_context_restore
 #if CTX_INCLUDE_FPREGS
 	.global	fpregs_context_save
@@ -111,6 +112,36 @@ endfunc el1_sysregs_context_save
 /* -----------------------------------------------------
  * The following function strictly follows the AArch64
  * PCS to use x9-x17 (temporary caller-saved registers)
+ * to do post operations after saving the EL1 system
+ * register context.
+ * -----------------------------------------------------
+ */
+func el1_sysregs_context_save_post_ops
+#if ENABLE_SPE_FOR_LOWER_ELS
+	/* Detect if SPE is implemented */
+	mrs	x9, id_aa64dfr0_el1
+	ubfx	x9, x9, #ID_AA64DFR0_PMS_SHIFT, #ID_AA64DFR0_PMS_LENGTH
+	cmp	x9, #0x1
+	b.ne	1f
+
+	/*
+	 * Before switching from normal world to secure world
+	 * the profiling buffers need to be drained out to memory.  This is
+	 * required to avoid an invalid memory access when TTBR is switched
+	 * for entry to SEL1.
+	 */
+	.arch	armv8.2-a+profile
+	psb	csync
+	dsb	nsh
+	.arch	armv8-a
+1:
+#endif
+	ret
+endfunc el1_sysregs_context_save_post_ops
+
+/* -----------------------------------------------------
+ * The following function strictly follows the AArch64
+ * PCS to use x9-x17 (temporary caller-saved registers)
  * to restore EL1 system register context.  It assumes
  * that 'x0' is pointing to a 'el1_sys_regs' structure
  * from where the register context will be restored
@@ -343,7 +374,7 @@ func restore_gp_registers_callee_eret
 	ldp	x24, x25, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X24]
 	ldp	x26, x27, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X26]
 	ldp	x28, x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X28]
-	ldp	 x30, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
+	ldp	x30, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
 	msr	sp_el0, x17
 	ldp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
 	eret
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 11ff1632..5257bf1c 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -218,7 +218,7 @@ void cm_init_my_context(const entry_point_info_t *ep)
  ******************************************************************************/
 void cm_prepare_el3_exit(uint32_t security_state)
 {
-	uint32_t sctlr_elx, scr_el3;
+	uint32_t sctlr_elx, scr_el3, mdcr_el2;
 	cpu_context_t *ctx = cm_get_context(security_state);
 
 	assert(ctx);
@@ -315,6 +315,13 @@ void cm_prepare_el3_exit(uint32_t security_state)
 			 * relying on hw. Some fields are architecturally
 			 * UNKNOWN on reset.
 			 *
+			 * MDCR_EL2.TPMS (ARM v8.2): Do not trap statistical
+			 * profiling controls to EL2.
+			 *
+			 * MDCR_EL2.E2PB (ARM v8.2): SPE enabled in non-secure
+			 * state. Accesses to profiling buffer controls at
+			 * non-secure EL1 are not trapped to EL2.
+			 *
 			 * MDCR_EL2.TDRA: Set to zero so that Non-secure EL0 and
 			 *  EL1 System register accesses to the Debug ROM
 			 *  registers are not trapped to EL2.
@@ -343,13 +350,32 @@ void cm_prepare_el3_exit(uint32_t security_state)
 			 * MDCR_EL2.HPMN: Set to value of PMCR_EL0.N which is the
 			 *  architecturally-defined reset value.
 			 */
-			write_mdcr_el2((MDCR_EL2_RESET_VAL |
+			mdcr_el2 = ((MDCR_EL2_RESET_VAL |
 					((read_pmcr_el0() & PMCR_EL0_N_BITS)
 					>> PMCR_EL0_N_SHIFT)) &
 					~(MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT
 					| MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT
 					| MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT
 					| MDCR_EL2_TPMCR_BIT));
+
+#if ENABLE_SPE_FOR_LOWER_ELS
+			uint64_t id_aa64dfr0_el1;
+
+			/* Detect if SPE is implemented */
+			id_aa64dfr0_el1 = read_id_aa64dfr0_el1() >>
+				ID_AA64DFR0_PMS_SHIFT;
+			if ((id_aa64dfr0_el1 & ID_AA64DFR0_PMS_MASK) == 1) {
+				/*
+				 * Make sure traps to EL2 are not generated if
+				 * EL2 is implemented but not used.
+				 */
+				mdcr_el2 &= ~MDCR_EL2_TPMS;
+				mdcr_el2 |= MDCR_EL2_E2PB(MDCR_EL2_E2PB_EL1);
+			}
+#endif
+
+			write_mdcr_el2(mdcr_el2);
+
 			/*
 			 * Initialise HSTR_EL2. All fields are architecturally
 			 * UNKNOWN on reset.
@@ -389,6 +415,7 @@ void cm_el1_sysregs_context_save(uint32_t security_state)
 	assert(ctx);
 
 	el1_sysregs_context_save(get_sysregs_ctx(ctx));
+	el1_sysregs_context_save_post_ops();
 }
 
 void cm_el1_sysregs_context_restore(uint32_t security_state)