Review and link kernel_module/user examples to README

kernel_module/user/anonymous_inode.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#anonymous-inode */
+
 #define _GNU_SOURCE
 #include <errno.h>
 #include <fcntl.h>

kernel_module/user/common.h

@@ -3,13 +3,17 @@
 
 #define _XOPEN_SOURCE 700
 #include <fcntl.h> /* open */
+#include <math.h> /* fabs */
 #include <stdint.h> /* uint64_t  */
 #include <stdlib.h> /* size_t */
+#include <stdio.h> /* snprintf */
+#include <sys/types.h>
 #include <unistd.h> /* pread, sysconf */
+#include <stdbool.h>
 
 /* Format documented at:
  * https://github.com/torvalds/linux/blob/v4.9/Documentation/vm/pagemap.txt
- **/
+ */
 typedef struct {
 	uint64_t pfn : 54;
 	unsigned int soft_dirty : 1;
@@ -33,8 +37,12 @@ int pagemap_get_entry(PagemapEntry *entry, int pagemap_fd, uintptr_t vaddr)
 
 	nread = 0;
 	while (nread < sizeof(data)) {
-		ret = pread(pagemap_fd, &data, sizeof(data),
-				(vaddr / sysconf(_SC_PAGE_SIZE)) * sizeof(data) + nread);
+		ret = pread(
+			pagemap_fd,
+			&data,
+			sizeof(data),
+			(vaddr / sysconf(_SC_PAGE_SIZE)) * sizeof(data) + nread
+		);
 		nread += ret;
 		if (ret <= 0) {
 			return 1;
@@ -74,4 +82,18 @@ int virt_to_phys_user(uintptr_t *paddr, pid_t pid, uintptr_t vaddr)
 	return 0;
 }
 
+bool common_vector_equal(size_t n, double * v1, double * v2, double max_err)
+{
+	double sum = 0.0;
+	double diff;
+	size_t i;
+	for (i = 0; i < n; ++i) {
+		diff = v1[i] - v2[i];
+		sum += diff * diff;
+	}
+	if (sqrt(sum)/n > max_err)
+		return false;
+	return true;
+}
+
 #endif

kernel_module/user/ctrl_alt_del.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#ctrl-alt-del */
+
 #define _XOPEN_SOURCE 700
 #include <signal.h>
 #include <stdio.h>

kernel_module/user/eigen.cpp

@@ -1,4 +1,6 @@
-/* Adapted from: https://eigen.tuxfamily.org/dox/GettingStarted.html */
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#eigen
+ * Adapted from: https://eigen.tuxfamily.org/dox/GettingStarted.html
+ */
 #include <iostream>
 #include <Eigen/Dense>
 int main() {

kernel_module/user/eigen_svd.cpp

@@ -1,24 +0,0 @@
-/* Adapted from: https://eigen.tuxfamily.org/dox/classEigen_1_1JacobiSVD.html */
-
-#include <iostream>
-using std::cout;
-using std::endl;
-
-#include <Eigen/Core>
-#include <Eigen/SVD>
-using Eigen::ComputeThinU;
-using Eigen::ComputeThinV;
-using Eigen::JacobiSVD;
-using Eigen::MatrixXf;
-using Eigen::Vector3f;
-
-int main() {
-	MatrixXf m = MatrixXf::Random(3,2);
-	JacobiSVD<MatrixXf> svd(m, ComputeThinU | ComputeThinV);
-	Vector3f rhs(1, 0, 0);
-	cout << "m = " << endl << m << endl << endl;
-	cout << "svd.singularValues() = " << endl << svd.singularValues() << endl << endl;
-	cout << "svd.MatrixU() = " << endl << svd.matrixU() << endl << endl;
-	cout << "svd.MatrixV() = " << endl << svd.matrixV() << endl << endl;
-	cout << "svd.solve() = " << endl << svd.solve(rhs) << endl << endl;
-}

kernel_module/user/libdrm_modeset.c

@@ -1,4 +1,5 @@
-/* Adapted from: https://github.com/dvdhrm/docs/blob/fad7c3203b14e67053e0fc41d8490138b8ff47dd/drm-howto/modeset.c */
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#drm
+ * Adapted from: https://github.com/dvdhrm/docs/blob/fad7c3203b14e67053e0fc41d8490138b8ff47dd/drm-howto/modeset.c */
 
 /*
  * modeset - DRM Modesetting Example

kernel_module/user/m5ops.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#m5ops-instructions */
+
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>

kernel_module/user/mmap.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#mmap */
+
 #define _XOPEN_SOURCE 700
 #include <assert.h>
 #include <fcntl.h>

kernel_module/user/myinsmod.c

@@ -1,4 +1,4 @@
-/* https://github.com/cirosantilli/linux-kernel-module-cheat#kernel-module-parameters#myinsmod */
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#myinsmod */
 
 #define _GNU_SOURCE
 #include <fcntl.h>

kernel_module/user/myrmmod.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#myinsmod */
+
 #define _GNU_SOURCE
 #include <fcntl.h>
 #include <stdio.h>

kernel_module/user/openblas.c

@@ -1,15 +1,16 @@
-/* Adapted from: https://github.com/xianyi/OpenBLAS/wiki/User-Manual/59b62f98e7400270fb03ad1d85fba5b64ebbff2b#call-cblas-interface */
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#blas
+ * Adapted from: https://github.com/xianyi/OpenBLAS/wiki/User-Manual/59b62f98e7400270fb03ad1d85fba5b64ebbff2b#call-cblas-interface */
 
+#include "common.h"
+
+#include <assert.h>
 #include <cblas.h>
-#include <stdio.h>
 
-int main() {
-	size_t i = 0;
-	double A[6] = {1.0,2.0,1.0,-3.0,4.0,-1.0};
-	double B[6] = {1.0,2.0,1.0,-3.0,4.0,-1.0};
-	double C[9] = {.5,.5,.5,.5,.5,.5,.5,.5,.5};
-	cblas_dgemm(CblasColMajor, CblasNoTrans, CblasTrans,3,3,2,1,A, 3, B, 3,2,C,3);
-	for(i = 0; i < 9; i++)
-		printf("%f ", C[i]);
-	printf("\n");
+int main()
+{
+	double A[6] = {1.0, 2.0, 1.0, -3.0, 4.0, -1.0};
+	double B[6] = {1.0, 2.0, 1.0, -3.0, 4.0, -1.0};
+	double C[9] = {0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5};
+	cblas_dgemm(CblasColMajor, CblasNoTrans, CblasTrans, 3, 3, 2, 1, A, 3, B, 3, 2, C, 3);
+	assert(common_vector_equal(9, C, (double[]){11.0, -9.0, 5.0, -9.0, 21.0, -1.0, 5.0, -1.0, 3.0}, 1e-6));
 }

kernel_module/user/openmp.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#openmp */
+
 #include <omp.h>
 #include <stdio.h>
 #include <stdlib.h>

kernel_module/user/poll.c

@@ -1,3 +1,5 @@
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#poll */
+
 #define _XOPEN_SOURCE 700
 #include <assert.h>
 #include <fcntl.h> /* creat, O_CREAT */

kernel_module/user/rdtsc.c

@@ -1,9 +1,4 @@
-/*
-Only works in x86_64.
-
-- https://en.wikipedia.org/wiki/Time_Stamp_Counter
-- https://stackoverflow.com/questions/9887839/clock-cycle-count-wth-gcc/9887979
-*/
+/* https://github.com/cirosantilli/linux-kernel-module-cheat#rdtsc */
 
 #include <stdint.h>
 #include <stdio.h>