[v2,04/13] Hugetlb: Migrating libhugetlbfs mprotect

diff --git a/runtest/hugetlb b/runtest/hugetlb
index 8e80db140..8ade3c9ec 100644
--- a/runtest/hugetlb
+++ b/runtest/hugetlb
@@ -24,6 +24,7 @@  hugemmap19 hugemmap19
 hugemmap20 hugemmap20
 hugemmap21 hugemmap21
 hugemmap22 hugemmap22
+hugemmap23 hugemmap23
 hugemmap05_1 hugemmap05 -m
 hugemmap05_2 hugemmap05 -s
 hugemmap05_3 hugemmap05 -s -m
diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
index 0fd01dbce..ffd831f2e 100644
--- a/testcases/kernel/mem/.gitignore
+++ b/testcases/kernel/mem/.gitignore
@@ -23,6 +23,7 @@ 
 /hugetlb/hugemmap/hugemmap20
 /hugetlb/hugemmap/hugemmap21
 /hugetlb/hugemmap/hugemmap22
+/hugetlb/hugemmap/hugemmap23
 /hugetlb/hugeshmat/hugeshmat01
 /hugetlb/hugeshmat/hugeshmat02
 /hugetlb/hugeshmat/hugeshmat03
diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap23.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap23.c
new file mode 100644
index 000000000..dcb9abff7
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap23.c
@@ -0,0 +1,226 @@ 
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/*
+ * Copyright (C) 2005-2006 IBM Corporation.
+ * Author: David Gibson & Adam Litke
+ */
+
+/*\
+ * [Description]
+ *
+ * This test uses mprotect to change protection of hugepage mapping and
+ * perform read/write operation. It checks if the operation results in
+ * expected behaviour as per the protection.
+ */
+#include <setjmp.h>
+#include "hugetlb.h"
+
+#define MNTPOINT "hugetlbfs/"
+#define RANDOM_CONSTANT 0x1234ABCD
+
+static int fd = -1;
+static sigjmp_buf sig_escape;
+static void *sig_expected = MAP_FAILED;
+static long hpage_size;
+static void *addr;
+static struct testcase {
+	char *tname;
+	unsigned long len1;
+	int prot1;
+	char *prot1_str;
+	unsigned long len2;
+	int prot2;
+	char *prot2_str;
+} tcases[] = {
+	{"R->RW", 1, PROT_READ, "PROT_READ",
+		1, PROT_READ|PROT_WRITE, "PROT_READ|PROT_WRITE"},
+
+	{"RW->R", 1, PROT_READ|PROT_WRITE, "PROT_READ|PROT_WRITE",
+		1, PROT_READ, "PROT_READ"},
+
+	{"R->RW 1/2", 2, PROT_READ, "PROT_READ",
+		1, PROT_READ|PROT_WRITE, "PROT_READ|PROT_WRITE"},
+
+	{"RW->R 1/2", 2, PROT_READ|PROT_WRITE, "PROT_READ|PROT_WRITE",
+		1, PROT_READ, "PROT_READ"},
+
+	{"NONE->R", 1, PROT_NONE, "PROT_NONE",
+		1, PROT_READ, "PROT_READ"},
+
+	{"NONE->RW", 1, PROT_NONE, "PROT_NONE",
+		1, PROT_READ|PROT_WRITE, "PROT_READ|PROT_WRITE"},
+};
+
+static void sig_handler(int signum, siginfo_t *si, void *uc)
+{
+	(void)uc;
+	if (signum == SIGSEGV) {
+		tst_res(TINFO, "SIGSEGV at %p (sig_expected=%p)", si->si_addr,
+		       sig_expected);
+		if (si->si_addr == sig_expected)
+			siglongjmp(sig_escape, 1);
+		tst_res(TFAIL, "SIGSEGV somewhere unexpected");
+	} else
+		tst_res(TFAIL, "Unexpected signal %s", strsignal(signum));
+}
+
+static int test_read(void *p)
+{
+	volatile unsigned long *pl = p;
+	unsigned long x;
+
+	if (sigsetjmp(sig_escape, 1)) {
+		/* We got a SEGV */
+		sig_expected = MAP_FAILED;
+		return -1;
+	}
+
+	sig_expected = p;
+	barrier();
+	x = *pl;
+	tst_res(TINFO, "Read back %lu", x);
+	barrier();
+	sig_expected = MAP_FAILED;
+	return 0;
+}
+
+static int test_write(void *p, unsigned long val)
+{
+	volatile unsigned long *pl = p;
+	unsigned long x;
+
+	if (sigsetjmp(sig_escape, 1)) {
+		/* We got a SEGV */
+		sig_expected = MAP_FAILED;
+		return -1;
+	}
+
+	sig_expected = p;
+	barrier();
+	*pl = val;
+	x = *pl;
+	barrier();
+	sig_expected = MAP_FAILED;
+
+	return (x != val);
+}
+
+static int test_prot(void *p, int prot, char *prot_str)
+{
+	int r, w;
+
+	r = test_read(p);
+	tst_res(TINFO, "On Read: %d", r);
+	w = test_write(p, RANDOM_CONSTANT);
+	tst_res(TINFO, "On Write: %d", w);
+
+	if (prot & PROT_READ) {
+		if (r != 0) {
+			tst_res(TFAIL, "read failed on mmap(prot %s)", prot_str);
+			return -1;
+		}
+
+	} else {
+		if (r != -1) {
+			tst_res(TFAIL, "read succeeded on mmap(prot %s)", prot_str);
+			return -1;
+		}
+	}
+
+	if (prot & PROT_WRITE) {
+		switch (w) {
+		case -1:
+			tst_res(TFAIL, "write failed on mmap(prot %s)", prot_str);
+			return -1;
+		case 0:
+			break;
+		case 1:
+			tst_res(TFAIL, "write mismatch on mmap(prot %s)", prot_str);
+			return -1;
+		default:
+			tst_res(TWARN, "Bug in test");
+			return -1;
+		}
+	} else {
+		switch (w) {
+		case -1:
+			break;
+		case 0:
+			tst_res(TFAIL, "write succeeded on mmap(prot %s)", prot_str);
+			return -1;
+		case 1:
+			tst_res(TFAIL, "write mismatch on mmap(prot %s)", prot_str);
+			return -1;
+		default:
+			tst_res(TWARN, "Bug in test");
+			break;
+		}
+	}
+	return 0;
+}
+
+static void run_test(unsigned int num)
+{
+	void *p;
+	int ret;
+
+	tst_res(TINFO, "Test Name: %s", tcases[num].tname);
+
+	p = SAFE_MMAP(NULL, tcases[num].len1*hpage_size,
+			tcases[num].prot1, MAP_SHARED, fd, 0);
+
+	ret = test_prot(p, tcases[num].prot1, tcases[num].prot1_str);
+	if (ret)
+		goto cleanup;
+	ret = mprotect(p, tcases[num].len2*hpage_size, tcases[num].prot2);
+	if (ret != 0) {
+		tst_res(TFAIL|TERRNO, "%s: mprotect(prot %s)",
+				tcases[num].tname, tcases[num].prot2_str);
+		goto cleanup;
+	}
+
+	ret = test_prot(p, tcases[num].prot2, tcases[num].prot2_str);
+	if (ret)
+		goto cleanup;
+	if (tcases[num].len2 < tcases[num].len1)
+		ret = test_prot(p + tcases[num].len2*hpage_size, tcases[num].prot1,
+				tcases[num].prot1_str);
+
+	tst_res(TPASS, "Successfully tested mprotect %s", tcases[num].tname);
+cleanup:
+	SAFE_MUNMAP(p, tcases[num].len1*hpage_size);
+}
+
+static void setup(void)
+{
+	struct sigaction sa = {
+		.sa_sigaction = sig_handler,
+		.sa_flags = SA_SIGINFO,
+	};
+
+	hpage_size = tst_get_hugepage_size();
+	SAFE_SIGACTION(SIGSEGV, &sa, NULL);
+
+	fd = tst_creat_unlinked(MNTPOINT, 0);
+	addr = SAFE_MMAP(NULL, 2*hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	memset(addr, 0, hpage_size);
+	SAFE_MUNMAP(addr, hpage_size);
+}
+
+static void cleanup(void)
+{
+	SAFE_MUNMAP(addr+hpage_size, hpage_size);
+	if (fd >= 0)
+		SAFE_CLOSE(fd);
+}
+
+static struct tst_test test = {
+	.tcnt = ARRAY_SIZE(tcases),
+	.needs_root = 1,
+	.mntpoint = MNTPOINT,
+	.needs_hugetlbfs = 1,
+	.needs_tmpdir = 1,
+	.setup = setup,
+	.cleanup = cleanup,
+	.test = run_test,
+	.hugepages = {2, TST_NEEDS},
+};
diff --git a/testcases/kernel/mem/hugetlb/lib/hugetlb.h b/testcases/kernel/mem/hugetlb/lib/hugetlb.h
index a4300f40f..efca65cd6 100644
--- a/testcases/kernel/mem/hugetlb/lib/hugetlb.h
+++ b/testcases/kernel/mem/hugetlb/lib/hugetlb.h
@@ -30,6 +30,15 @@ 
 #define SHM_HUGETLB	04000	/* segment is mapped via hugetlb */
 #endif
 
+#ifndef barrier
+# ifdef mb
+	/* Redefining the mb() */
+#   define barrier() mb()
+# else
+#   define barrier() __asm__ __volatile__ ("" : : : "memory")
+# endif
+#endif
+
 /*
  * to get the lower nine permission bits
  * from shmid_ds.ipc_perm.mode