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The following commit(s) were added to refs/heads/master by this push:
new 63aefd9975b arch/armv7-r: userspace PMU access
63aefd9975b is described below
commit 63aefd9975b926ebf28e7b383eb332423a883463
Author: hujun5 <[email protected]>
AuthorDate: Sun Sep 7 10:35:03 2025 +0800
arch/armv7-r: userspace PMU access
This change enables performance monitoring unit (PMU) access from userspace
on ARMv7-R architecture by adding CONFIG_ARCH_HAVE_PERF_EVENTS_USER_ACCESS
support and building PMU code for userspace when needed.
Signed-off-by: hujun5 <[email protected]>
---
.../arm/qemu/boards/qemu-armv7r/index.rst | 95 +++++++++++++++++++++-
arch/arm/Kconfig | 1 +
arch/arm/src/armv7-r/CMakeLists.txt | 5 ++
arch/arm/src/armv7-r/Make.defs | 4 +
arch/arm/src/armv7-r/arm_perf.c | 13 +--
sched/clock/clock_perf.c | 4 +-
6 files changed, 112 insertions(+), 10 deletions(-)
diff --git a/Documentation/platforms/arm/qemu/boards/qemu-armv7r/index.rst
b/Documentation/platforms/arm/qemu/boards/qemu-armv7r/index.rst
index 8b417aa8ed2..39800ee33fc 100644
--- a/Documentation/platforms/arm/qemu/boards/qemu-armv7r/index.rst
+++ b/Documentation/platforms/arm/qemu/boards/qemu-armv7r/index.rst
@@ -41,7 +41,7 @@ NSH (Flat Build)
Configuring NuttX and compile::
$ ./tools/configure.sh -l qemu-armv7r:nsh
- $ make -j`nproc`
+ $ make -j$(nproc)
Running with qemu::
@@ -58,7 +58,7 @@ with MPU support::
$ cd nuttx
$ ./tools/configure.sh qemu-armv7r:pnsh
- $ make -j`nproc`
+ $ make -j$(nproc)
Running with qemu (note: both nuttx and nuttx_user must be loaded)::
@@ -106,4 +106,93 @@ The nuttx ELF image can be debugged with QEMU.
$ arm-none-eabi-gdb -tui --eval-command='target remote localhost:1234'
nuttx
(gdb) add-symbol-file nuttx_user
- (gdb) c
\ No newline at end of file
+ (gdb) c
+
+=====================
+Userspace PMU Access
+=====================
+
+Overview
+========
+
+This document describes how to enable and use Performance Monitoring Unit (PMU)
+access from userspace applications on the ARM v7-R QEMU board. The PMU provides
+hardware performance counters that can be used to analyze and profile
application
+performance.
+
+1. ARM v7-R QEMU board support
+2. NuttX kernel with PMU support enabled
+3. User-space access permissions configured
+
+Kernel Configuration
+--------------------
+
+To enable PMU support and userspace access, add the following configuration
+options to your defconfig::
+
+ +CONFIG_ARCH_PERF_EVENTS_USER_ACCESS=y
+ +CONFIG_ARCH_PERF_EVENTS=y
+
+
+Userspace API
+
+**perf_gettime**
+================
+
+Basic Usage
+-----------
+
+.. code-block:: c
+
+ clock_t start, end;
+ unsigned long frequency;
+ unsigned long cycles;
+
+ frequency = perf_getfreq();
+ if (frequency == 0) {
+ printf("ERROR: Performance frequency not available\n");
+ return;
+ }
+
+ printf("Operation Profiling Results:\n");
+ printf("CPU Frequency: %lu Hz\n\n", frequency);
+ printf("%-40s | %-12s | %-12s\n", "Operation", "Cycles", "Time (us)");
+ printf("%-40s-+-%-12s-+-%-12s\n",
+ "----------------------------------------",
+ "------------", "------------");
+
+ start = perf_gettime();
+ result = 1;
+ for (int i = 1; i < 1000; i++) {
+ result *= i;
+ }
+
+ end = perf_gettime();
+ cycles = end - start;
+ printf("%-40s | %12lu | %12lu\n", "Multiplication (1K times)", cycles,
(cycles * 1000000UL) / frequency);
+
+ start = perf_gettime();
+ result = 1000000;
+ for (int i = 1; i < 1000; i++) {
+ result /= (i + 1);
+ }
+ end = perf_gettime();
+ cycles = end - start;
+
+ printf("%-40s | %12lu | %12lu\n", "Division (1K times)", cycles, (cycles *
1000000UL) / frequency);
+
+Testing with QEMU
+=================
+
+PNSH (Protected) Configuration
+-------------------------------
+
+For protected build with userspace PMU access::
+
+ $ ./tools/configure.sh qemu-armv7r:pnsh
+ $ make -j$(nproc)
+
+2. Run QEMU (load both kernel and userspace)::
+
+ $ qemu-system-arm -M virt -semihosting -nographic -cpu cortex-r5f -device
loader,file=nuttx_user -device loader,file=nuttx
+
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 68c44b660cb..b555909041c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1005,6 +1005,7 @@ config ARCH_ARMV7R
default n
select ARCH_HAVE_CPUINFO
select ARCH_HAVE_PERF_EVENTS
+ select ARCH_HAVE_PERF_EVENTS_USER_ACCESS
config ARCH_CORTEXR4
bool
diff --git a/arch/arm/src/armv7-r/CMakeLists.txt
b/arch/arm/src/armv7-r/CMakeLists.txt
index f127f628ae4..7db5e42d837 100644
--- a/arch/arm/src/armv7-r/CMakeLists.txt
+++ b/arch/arm/src/armv7-r/CMakeLists.txt
@@ -81,3 +81,8 @@ if(CONFIG_SMP)
endif()
target_sources(arch PRIVATE ${SRCS})
+
+if(NOT CONFIG_BUILD_FLAT AND CONFIG_ARCH_HAVE_PERF_EVENTS_USER_ACCESS)
+ target_sources(arch_interface PRIVATE arm_perf.c)
+ target_include_directories(arch_interface PRIVATE ${NUTTX_CHIP_ABS_DIR})
+endif()
diff --git a/arch/arm/src/armv7-r/Make.defs b/arch/arm/src/armv7-r/Make.defs
index 70480712b2b..0a9bebcb496 100644
--- a/arch/arm/src/armv7-r/Make.defs
+++ b/arch/arm/src/armv7-r/Make.defs
@@ -67,3 +67,7 @@ ifeq ($(CONFIG_SMP),y)
CMN_CSRCS += arm_cpustart.c arm_smpcall.c
CMN_CSRCS += arm_cpuidlestack.c arm_scu.c
endif
+
+ifeq ($(CONFIG_ARCH_HAVE_PERF_EVENTS_USER_ACCESS),y)
+ CMN_UCSRCS += arm_perf.c
+endif
diff --git a/arch/arm/src/armv7-r/arm_perf.c b/arch/arm/src/armv7-r/arm_perf.c
index d32a7a365e1..7f96b6b0075 100644
--- a/arch/arm/src/armv7-r/arm_perf.c
+++ b/arch/arm/src/armv7-r/arm_perf.c
@@ -33,6 +33,7 @@
#ifdef CONFIG_ARCH_HAVE_PERF_EVENTS
+#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
/****************************************************************************
* Private Data
****************************************************************************/
@@ -84,11 +85,6 @@ unsigned long up_perf_getfreq(void)
return g_cpu_freq;
}
-clock_t up_perf_gettime(void)
-{
- return cp15_pmu_rdccr();
-}
-
void up_perf_convert(clock_t elapsed, struct timespec *ts)
{
clock_t left;
@@ -97,4 +93,11 @@ void up_perf_convert(clock_t elapsed, struct timespec *ts)
left = elapsed - ts->tv_sec * g_cpu_freq;
ts->tv_nsec = NSEC_PER_SEC * (uint64_t)left / g_cpu_freq;
}
+#endif /* CONFIG_BUILD_FLAT || __KERNEL__ */
+
+clock_t up_perf_gettime(void)
+{
+ return cp15_pmu_rdccr();
+}
+
#endif
diff --git a/sched/clock/clock_perf.c b/sched/clock/clock_perf.c
index 33c8398410c..8d0a6347073 100644
--- a/sched/clock/clock_perf.c
+++ b/sched/clock/clock_perf.c
@@ -31,7 +31,7 @@
#include <nuttx/spinlock.h>
#include <nuttx/wdog.h>
-#ifndef CONFIG_ARCH_HAVE_PERF_EVENTS_USER_ACCESS
+#ifndef CONFIG_ARCH_PERF_EVENTS_USER_ACCESS
/****************************************************************************
* Preprocessors
@@ -134,7 +134,7 @@ clock_t perf_gettime(void)
}
# endif
-#endif /* !CONFIG_ARCH_HAVE_PERF_EVENTS_USER_ACCESS */
+#endif /* !CONFIG_ARCH_PERF_EVENTS_USER_ACCESS */
#if defined(CONFIG_ALARM_ARCH) || defined (CONFIG_TIMER_ARCH) || \
defined(CONFIG_ARCH_PERF_EVENTS)
