Add PMF instrumentation points in TF
In order to quantify the overall time spent in the PSCI software
implementation, an initial collection of PMF instrumentation points
has been added.
Instrumentation has been added to the following code paths:
- Entry to PSCI SMC handler. The timestamp is captured as early
as possible during the runtime exception and stored in memory
before entering the PSCI SMC handler.
- Exit from PSCI SMC handler. The timestamp is captured after
normal return from the PSCI SMC handler or if a low power state
was requested it is captured in the bl31 warm boot path before
return to normal world.
- Entry to low power state. The timestamp is captured before entry
to a low power state which implies either standby or power down.
As these power states are mutually exclusive, only one timestamp
is defined to describe both. It is possible to differentiate between
the two power states using the PSCI STAT interface.
- Exit from low power state. The timestamp is captured after a standby
or power up operation has completed.
To calculate the number of cycles spent running code in Trusted Firmware
one can perform the following calculation:
(exit_psci - enter_psci) - (exit_low_pwr - enter_low_pwr).
The resulting number of cycles can be converted to time given the
frequency of the counter.
Change-Id: Ie3b8f3d16409b6703747093b3a2d5c7429ad0166
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
diff --git a/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index 4c3a515..d14a68d 100644
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -31,6 +31,8 @@
#include <arch.h>
#include <bl_common.h>
#include <el3_common_macros.S>
+#include <pmf_asm_macros.S>
+#include <runtime_instr.h>
#include <xlat_tables.h>
.globl bl31_entrypoint
@@ -141,6 +143,18 @@
* --------------------------------------------------------------------
*/
func bl31_warm_entrypoint
+#if ENABLE_RUNTIME_INSTRUMENTATION
+
+ /*
+ * This timestamp update happens with cache off. The next
+ * timestamp collection will need to do cache maintenance prior
+ * to timestamp update.
+ */
+ pmf_calc_timestamp_addr rt_instr_svc RT_INSTR_EXIT_HW_LOW_PWR
+ mrs x1, cntpct_el0
+ str x1, [x0]
+#endif
+
/*
* On the warm boot path, most of the EL3 initialisations performed by
* 'el3_entrypoint_common' must be skipped:
@@ -188,5 +202,23 @@
bl psci_warmboot_entrypoint
+#if ENABLE_RUNTIME_INSTRUMENTATION
+ pmf_calc_timestamp_addr rt_instr_svc RT_INSTR_EXIT_PSCI
+ mov x19, x0
+
+ /*
+ * Invalidate before updating timestamp to ensure previous timestamp
+ * updates on the same cache line with caches disabled are properly
+ * seen by the same core. Without the cache invalidate, the core might
+ * write into a stale cache line.
+ */
+ mov x1, #PMF_TS_SIZE
+ mov x20, x30
+ bl inv_dcache_range
+ mov x30, x20
+
+ mrs x0, cntpct_el0
+ str x0, [x19]
+#endif
b el3_exit
endfunc bl31_warm_entrypoint
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 799062e..f333bf1 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -31,6 +31,7 @@
#include <arch.h>
#include <asm_macros.S>
#include <context.h>
+#include <cpu_data.h>
#include <interrupt_mgmt.h>
#include <platform_def.h>
#include <runtime_svc.h>
@@ -47,6 +48,21 @@
msr daifclr, #DAIF_ABT_BIT
str x30, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
+
+#if ENABLE_RUNTIME_INSTRUMENTATION
+
+ /*
+ * Read the timestamp value and store it in per-cpu data.
+ * The value will be extracted from per-cpu data by the
+ * C level SMC handler and saved to the PMF timestamp region.
+ */
+ mrs x30, cntpct_el0
+ str x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29]
+ mrs x29, tpidr_el3
+ str x30, [x29, #CPU_DATA_PMF_TS0_OFFSET]
+ ldr x29, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X29]
+#endif
+
mrs x30, esr_el3
ubfx x30, x30, #ESR_EC_SHIFT, #ESR_EC_LENGTH
diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index fae5ee4..85b3ea1 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -36,9 +36,16 @@
#include <context_mgmt.h>
#include <debug.h>
#include <platform.h>
+#include <pmf.h>
+#include <runtime_instr.h>
#include <runtime_svc.h>
#include <string.h>
+#if ENABLE_RUNTIME_INSTRUMENTATION
+PMF_REGISTER_SERVICE_SMC(rt_instr_svc, PMF_RT_INSTR_SVC_ID,
+ RT_INSTR_TOTAL_IDS, PMF_STORE_ENABLE)
+#endif
+
/*******************************************************************************
* This function pointer is used to initialise the BL32 image. It's initialized
* by SPD calling bl31_register_bl32_init after setting up all things necessary