selftests/vm: add a test for virtual address range mapping

This verifies virtual address mapping below and above the 128TB range
and makes sure that address returned are within the expected range
depending upon the hint passed from the user space.

Link: http://lkml.kernel.org/r/20170418095252.20533-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/vm/Makefile

@@ -16,6 +16,7 @@ TEST_GEN_FILES += thuge-gen
 TEST_GEN_FILES += transhuge-stress
 TEST_GEN_FILES += userfaultfd
 TEST_GEN_FILES += mlock-random-test
+TEST_GEN_FILES += virtual_address_range
 
 TEST_PROGS := run_vmtests
 

tools/testing/selftests/vm/run_vmtests

@@ -165,4 +165,15 @@ else
 	echo "[PASS]"
 fi
 
+echo "-----------------------------"
+echo "running virtual_address_range"
+echo "-----------------------------"
+./virtual_address_range
+if [ $? -ne 0 ]; then
+	echo "[FAIL]"
+	exitcode=1
+else
+	echo "[PASS]"
+fi
+
 exit $exitcode

tools/testing/selftests/vm/virtual_address_range.c

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2017, Anshuman Khandual, IBM Corp.
+ * Licensed under GPLv2.
+ *
+ * Works on architectures which support 128TB virtual
+ * address range and beyond.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <numaif.h>
+#include <sys/mman.h>
+#include <sys/time.h>
+
+/*
+ * Maximum address range mapped with a single mmap()
+ * call is little bit more than 16GB. Hence 16GB is
+ * chosen as the single chunk size for address space
+ * mapping.
+ */
+#define MAP_CHUNK_SIZE   17179869184UL /* 16GB */
+
+/*
+ * Address space till 128TB is mapped without any hint
+ * and is enabled by default. Address space beyond 128TB
+ * till 512TB is obtained by passing hint address as the
+ * first argument into mmap() system call.
+ *
+ * The process heap address space is divided into two
+ * different areas one below 128TB and one above 128TB
+ * till it reaches 512TB. One with size 128TB and the
+ * other being 384TB.
+ */
+#define NR_CHUNKS_128TB   8192UL /* Number of 16GB chunks for 128TB */
+#define NR_CHUNKS_384TB  24576UL /* Number of 16GB chunks for 384TB */
+
+#define ADDR_MARK_128TB  (1UL << 47) /* First address beyond 128TB */
+
+static char *hind_addr(void)
+{
+	int bits = 48 + rand() % 15;
+
+	return (char *) (1UL << bits);
+}
+
+static int validate_addr(char *ptr, int high_addr)
+{
+	unsigned long addr = (unsigned long) ptr;
+
+	if (high_addr) {
+		if (addr < ADDR_MARK_128TB) {
+			printf("Bad address %lx\n", addr);
+			return 1;
+		}
+		return 0;
+	}
+
+	if (addr > ADDR_MARK_128TB) {
+		printf("Bad address %lx\n", addr);
+		return 1;
+	}
+	return 0;
+}
+
+static int validate_lower_address_hint(void)
+{
+	char *ptr;
+
+	ptr = mmap((void *) (1UL << 45), MAP_CHUNK_SIZE, PROT_READ |
+			PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+	if (ptr == MAP_FAILED)
+		return 0;
+
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	char *ptr[NR_CHUNKS_128TB];
+	char *hptr[NR_CHUNKS_384TB];
+	char *hint;
+	unsigned long i, lchunks, hchunks;
+
+	for (i = 0; i < NR_CHUNKS_128TB; i++) {
+		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+		if (ptr[i] == MAP_FAILED) {
+			if (validate_lower_address_hint())
+				return 1;
+			break;
+		}
+
+		if (validate_addr(ptr[i], 0))
+			return 1;
+	}
+	lchunks = i;
+
+	for (i = 0; i < NR_CHUNKS_384TB; i++) {
+		hint = hind_addr();
+		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+		if (hptr[i] == MAP_FAILED)
+			break;
+
+		if (validate_addr(hptr[i], 1))
+			return 1;
+	}
+	hchunks = i;
+
+	for (i = 0; i < lchunks; i++)
+		munmap(ptr[i], MAP_CHUNK_SIZE);
+
+	for (i = 0; i < hchunks; i++)
+		munmap(hptr[i], MAP_CHUNK_SIZE);
+
+	return 0;
+}