From 270520b4a2eac8725c8575c3180964289722e191 Mon Sep 17 00:00:00 2001
From: John Ogness <john.ogness@linutronix.de>
Date: Tue, 19 Dec 2017 10:59:40 +0100
Subject: 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>
---
 schulung_tools/matrix/main.c | 91 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 schulung_tools/matrix/main.c

(limited to 'schulung_tools/matrix/main.c')

diff --git a/schulung_tools/matrix/main.c b/schulung_tools/matrix/main.c
new file mode 100644
index 0000000..9a6f2fa
--- /dev/null
+++ b/schulung_tools/matrix/main.c
@@ -0,0 +1,91 @@
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <errno.h>
+
+/* matrix dimension */
+static size_t dim;
+
+/* options */
+static struct option long_opts[] = {
+    { "dim", required_argument, NULL, 'd' },
+    { "1",   no_argument, NULL,       '1' },
+    { "2",   no_argument, NULL,       '2' },
+    { NULL,  0,                 NULL,  0  },
+};
+
+static int visit_every_element_1(const int *matrix, size_t dim)
+{
+    int sum = 0;
+
+    /* row by row */
+    for (int i = 0; i < dim; ++i) {
+        for (int j = 0; j < dim; ++j) {
+            sum += matrix[i * dim + j];
+        }
+    }
+
+    return sum;
+}
+
+static int visit_every_element_2(const int *matrix, size_t dim)
+{
+    int sum = 0;
+
+    /* column by column */
+    for (int j = 0; j < dim; ++j) {
+        for (int i = 0; i < dim; ++i) {
+            sum += matrix[i * dim + j];
+        }
+    }
+
+    return sum;
+}
+
+static inline void print_usage_and_die(void)
+{
+    fprintf(stderr, "usage: matrix [-1|-2] [-d <size>]\n");
+    exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv)
+{
+    int *matrix, sum;
+    char *end;
+    int c, choice = 1;
+
+    dim = 10000;
+    while ((c = getopt_long(argc, argv, "d:12", long_opts, NULL)) != -1) {
+        switch (c) {
+        case 'd':
+            dim = strtoull(optarg, &end, 10);
+            if (end == optarg || *end != '\0' || errno == ERANGE) {
+                fprintf(stderr, "given dim is not valid\n");
+                return EXIT_FAILURE;
+            }
+            break;
+        case '1':
+            choice = 1;
+            break;
+        case '2':
+            choice = 2;
+            break;
+        default:
+            print_usage_and_die();
+        }
+    }
+
+    matrix = (int *)calloc(dim * dim, sizeof(int));
+    if (!matrix) {
+        perror("malloc() failed");
+        return EXIT_FAILURE;
+    }
+
+    sum = choice == 1 ? visit_every_element_1(matrix, dim) :
+        visit_every_element_2(matrix, dim);
+    printf("Bogus result: %d\n", sum);
+
+    return EXIT_SUCCESS;
+}
-- 
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