Migrating the libhugetlbfs/testcases/shm-gettest.c test

Test Description: This testcase creates shared memory segments
backed by hugepages, writes  specific patterns to each segment,
verifies pattern and detaches a shared memory segments in a loop.

This looping test was added to verify the functionality of
large page backed shared memory segments. A segment is created,
written, verified, and detached a specified number of times.

Signed-off-by: Sachin P Bappalige <[email protected]>
Reviewed-by: Cyril Hrubis <[email protected]>

runtest/hugetlb

@@ -55,3 +55,4 @@ hugeshmget01 hugeshmget01 -i 10
 hugeshmget02 hugeshmget02 -i 10
 hugeshmget03 hugeshmget03 -i 10
 hugeshmget05 hugeshmget05 -i 10
+hugeshmget06 hugeshmget06 -i 10

testcases/kernel/mem/.gitignore

@@ -47,6 +47,7 @@
 /hugetlb/hugeshmget/hugeshmget02
 /hugetlb/hugeshmget/hugeshmget03
 /hugetlb/hugeshmget/hugeshmget05
+/hugetlb/hugeshmget/hugeshmget06
 /ksm/ksm01
 /ksm/ksm02
 /ksm/ksm03

testcases/kernel/mem/hugetlb/hugeshmget/hugeshmget06.c

@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2005-2006, IBM Corporation.
+ * Author: David Gibson & Adam Litke
+ */
+
+/*\
+ * [Description]
+ *
+ * This testcase creates shared memory segments backed by hugepages,
+ * writes specific patterns to each segment, verifies pattern,
+ * and detaches a shared memory segments in a loop.
+ * It ensures that the hugepage backed shared memory functionalities
+ * works correctly by validating the data written to segment.
+ */
+
+#include "hugetlb.h"
+#include "tst_safe_sysv_ipc.h"
+
+#define NR_HUGEPAGES 4
+
+static long hpage_size;
+static int shmid = -1;
+
+static void run_test(void)
+{
+	size_t i, j;
+	char pattern;
+	char *shmaddr;
+
+	shmaddr = SAFE_SHMAT(shmid, 0, SHM_RND);
+	tst_res(TINFO, "shmaddr: %p", shmaddr);
+
+	for (i = 0; i < NR_HUGEPAGES; i++) {
+		pattern = 65 + (i % 26);
+		tst_res(TDEBUG, "Touching %p with %c",
+		shmaddr + (i * hpage_size), pattern);
+		memset(shmaddr + (i * hpage_size), pattern, hpage_size);
+	}
+
+	for (i = 0; i < NR_HUGEPAGES; i++) {
+		pattern = 65 + (i % 26);
+		tst_res(TDEBUG, "Verifying %p", (shmaddr + (i * hpage_size)));
+		for (j = 0; j < (size_t)hpage_size; j++)
+			if (*(shmaddr + (i * hpage_size) + j) != pattern) {
+				tst_res(TFAIL, "Got wrong byte 0x%02x expected 0x%02x",
+						*(shmaddr + (i * hpage_size) + j),
+						pattern);
+				return;
+			}
+	}
+	SAFE_SHMDT((const void *)shmaddr);
+	tst_res(TPASS, "shm hugepages works correctly");
+}
+
+static void setup(void)
+{
+	hpage_size = tst_get_hugepage_size();
+	tst_res(TINFO, "hugepage size is %ld", hpage_size);
+	shmid = SAFE_SHMGET(IPC_PRIVATE, NR_HUGEPAGES * hpage_size, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
+	tst_res(TINFO, "shmid: 0x%x", shmid);
+}
+
+static void cleanup(void)
+{
+	if (shmid >= 0)
+		SAFE_SHMCTL(shmid, IPC_RMID, NULL);
+}
+
+static struct tst_test test = {
+	.needs_root = 1,
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run_test,
+	.hugepages = {NR_HUGEPAGES, TST_NEEDS},
+};