Refactor Statistical Profiling Extensions implementation
Factor out SPE operations in a separate file. Use the publish
subscribe framework to drain the SPE buffers before entering secure
world. Additionally, enable SPE before entering normal world.
A side effect of this change is that the profiling buffers are now
only drained when a transition from normal world to secure world
happens. Previously they were drained also on return from secure
world, which is unnecessary as SPE is not supported in S-EL1.
Change-Id: I17582c689b4b525770dbb6db098b3a0b5777b70a
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
diff --git a/lib/el3_runtime/aarch64/context.S b/lib/el3_runtime/aarch64/context.S
index 143da95..620ec16 100644
--- a/lib/el3_runtime/aarch64/context.S
+++ b/lib/el3_runtime/aarch64/context.S
@@ -9,7 +9,6 @@
#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
@@ -112,36 +111,6 @@
/* -----------------------------------------------------
* 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
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 479acc9..8f1523f 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -15,6 +15,7 @@
#include <platform_def.h>
#include <pubsub_events.h>
#include <smcc_helpers.h>
+#include <spe.h>
#include <string.h>
#include <utils.h>
@@ -216,6 +217,9 @@
static void enable_extensions_nonsecure(int el2_unused)
{
#if IMAGE_BL31
+#if ENABLE_SPE_FOR_LOWER_ELS
+ spe_enable(el2_unused);
+#endif
#endif
}
@@ -354,13 +358,6 @@
* 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.
@@ -397,22 +394,6 @@
| 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);
/*
@@ -454,7 +435,6 @@
assert(ctx);
el1_sysregs_context_save(get_sysregs_ctx(ctx));
- el1_sysregs_context_save_post_ops();
#if IMAGE_BL31
if (security_state == SECURE)
diff --git a/lib/extensions/spe/spe.c b/lib/extensions/spe/spe.c
new file mode 100644
index 0000000..3b297f2
--- /dev/null
+++ b/lib/extensions/spe/spe.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <pubsub.h>
+
+/*
+ * The assembler does not yet understand the psb csync mnemonic
+ * so use the equivalent hint instruction.
+ */
+#define psb_csync() asm volatile("hint #17")
+
+void spe_enable(int el2_unused)
+{
+ uint64_t features;
+
+ features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_PMS_SHIFT;
+ if ((features & ID_AA64DFR0_PMS_MASK) == 1) {
+ uint64_t v;
+
+ if (el2_unused) {
+ /*
+ * 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.
+ */
+ v = read_mdcr_el2();
+ v &= ~MDCR_EL2_TPMS;
+ v |= MDCR_EL2_E2PB(MDCR_EL2_E2PB_EL1);
+ write_mdcr_el2(v);
+ }
+
+ /*
+ * MDCR_EL2.NSPB (ARM v8.2): SPE enabled in Non-secure state
+ * and disabled in secure state. Accesses to SPE registers at
+ * S-EL1 generate trap exceptions to EL3.
+ */
+ v = read_mdcr_el3();
+ v |= MDCR_NSPB(MDCR_NSPB_EL1);
+ write_mdcr_el3(v);
+ }
+}
+
+void spe_disable(void)
+{
+ uint64_t features;
+
+ features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_PMS_SHIFT;
+ if ((features & ID_AA64DFR0_PMS_MASK) == 1) {
+ uint64_t v;
+
+ /* Drain buffered data */
+ psb_csync();
+ dsbnsh();
+
+ /* Disable profiling buffer */
+ v = read_pmblimitr_el1();
+ v &= ~(1ULL << 0);
+ write_pmblimitr_el1(v);
+ isb();
+ }
+}
+
+static void *spe_drain_buffers_hook(const void *arg)
+{
+ uint64_t features;
+
+ features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_PMS_SHIFT;
+ if ((features & ID_AA64DFR0_PMS_MASK) == 1) {
+ /* Drain buffered data */
+ psb_csync();
+ dsbnsh();
+ }
+
+ return 0;
+}
+
+SUBSCRIBE_TO_EVENT(cm_entering_secure_world, spe_drain_buffers_hook);