schulung_tools: add various demos and tools

Different tools have been used by various trainers as demos. Put
all these into master so they are available to all trainers.

ipc_pipe: ipc demo using pipes
ipc_shm: ipc demo using shared memory
libduma: source and instructions for compiling libduma
matrix: demo of good and bad cache access
mtrace: patch and infos for using mtrace with ASLR
rtex: demo of handling page faults

Signed-off-by: John Ogness <john.ogness@linutronix.de>

3 files changed, 137 insertions, 0 deletions

diff --git a/schulung_tools/ipc_pipe/Makefile b/schulung_tools/ipc_pipe/Makefile
new file mode 100644
index 0000000..a5c8404
--- /dev/null
+++ b/schulung_tools/ipc_pipe/Makefile
@@ -0,0 +1,12 @@
+CFLAGS=-O0 -g -Wall -pedantic -lpthread -std=gnu99
+LDFLAGS=-lpthread
+
+all: main
+
+main.o: main.c
+main: main.o
+
+clean:
+	rm -rf main *.o
+
+.PHONY: clean
diff --git a/schulung_tools/ipc_pipe/README b/schulung_tools/ipc_pipe/README
new file mode 100644
index 0000000..c0fccac
--- /dev/null
+++ b/schulung_tools/ipc_pipe/README
@@ -0,0 +1,10 @@
+#!/bin/sh
+
+# run test program
+sudo trace-cmd record \
+	-e sched:sched_switch \
+	-e sched:sched_wakeup \
+	taskset 1 chrt -f 80 ./main -s 1000000
+
+# view results
+kernelshark
diff --git a/schulung_tools/ipc_pipe/main.c b/schulung_tools/ipc_pipe/main.c
new file mode 100644
index 0000000..bda2da7
--- /dev/null
+++ b/schulung_tools/ipc_pipe/main.c
@@ -0,0 +1,115 @@
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <errno.h>
+
+/* pipe file descriptors */
+static int fd[2];
+
+/* send/write size */
+static size_t size;
+
+/* options */
+static struct option long_opts[] = {
+	{ "size", required_argument, NULL, 's' },
+	{ NULL,   0,                 NULL,  0  },
+};
+
+static void *reader(void *arg)
+{
+	unsigned char buf[size];
+	ssize_t read_ = 0;
+
+	while (read_ < size) {
+		ssize_t ret;
+
+		ret = read(fd[0], buf + read_, size - read_);
+		if (ret < 0) {
+			perror("read() failed");
+			exit(EXIT_FAILURE);
+		}
+		read_ += ret;
+	}
+
+	printf("Reader: got data\n");
+	return NULL;
+}
+
+static void *writer(void *arg)
+{
+	unsigned char buf[size];
+	ssize_t written = 0;
+
+	sleep(1);
+
+	while (written < size) {
+		ssize_t ret;
+
+		ret = write(fd[1], buf + written, size - written);
+		if (ret < 0) {
+			perror("write() failed");
+			exit(EXIT_FAILURE);
+		}
+
+		written += ret;
+	}
+
+	printf("Writer: sent data\n");
+
+	sleep(1);
+
+	return NULL;
+}
+
+static inline void print_usage_and_die(void)
+{
+	fprintf(stderr, "usage: pipedemo [-s <size>]\n");
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+	pthread_t tid1, tid2;
+	char *end;
+	int c;
+
+	size = 4 << 10;
+	while ((c = getopt_long(argc, argv, "s:", long_opts, NULL)) != -1) {
+		switch (c) {
+		case 's':
+			size = strtoull(optarg, &end, 10);
+			if (end == optarg || *end != '\0' || errno == ERANGE) {
+				fprintf(stderr, "given size is not valid\n");
+				return EXIT_FAILURE;
+			}
+			break;
+		default:
+			print_usage_and_die();
+		}
+	}
+
+	if (pipe(fd) < 0) {
+		perror("pipe() failed");
+		return EXIT_FAILURE;
+	}
+
+	if (pthread_create(&tid1, NULL, reader, NULL) ||
+	    pthread_create(&tid2, NULL, writer, NULL)) {
+		fprintf(stderr, "pthread_create() failed\n");
+		return EXIT_FAILURE;
+	}
+
+	if (pthread_setname_np(tid1, "pipedemo-reader") ||
+	    pthread_setname_np(tid2, "pipedemo-writer")) {
+		fprintf(stderr, "pthread_create() failed\n");
+		return EXIT_FAILURE;
+	}
+
+	pthread_join(tid1, NULL);
+	pthread_join(tid2, NULL);
+
+	return EXIT_SUCCESS;
+}