selftests: mm: fix build errors on armhf

The __NR_mmap isn't found on armhf.  The mmap() is commonly available
system call and its wrapper is present on all architectures.  So it should
be used directly.  It solves problem for armhf and doesn't create problem
for other architectures.

Remove sys_mmap() functions as they aren't doing anything else other than
calling mmap().  There is no need to set errno = 0 manually as glibc
always resets it.

For reference errors are as following:

  CC       seal_elf
seal_elf.c: In function 'sys_mmap':
seal_elf.c:39:33: error: '__NR_mmap' undeclared (first use in this function)
   39 |         sret = (void *) syscall(__NR_mmap, addr, len, prot,
      |                                 ^~~~~~~~~

mseal_test.c: In function 'sys_mmap':
mseal_test.c:90:33: error: '__NR_mmap' undeclared (first use in this function)
   90 |         sret = (void *) syscall(__NR_mmap, addr, len, prot,
      |                                 ^~~~~~~~~

Link: https://lkml.kernel.org/r/20240809082511.497266-1-usama.anjum@collabora.com
Fixes: 4926c7a ("selftest mm/mseal memory sealing")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/mm/mseal_test.c

@@ -81,17 +81,6 @@ static int sys_mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
 	return sret;
 }
 
-static void *sys_mmap(void *addr, unsigned long len, unsigned long prot,
-	unsigned long flags, unsigned long fd, unsigned long offset)
-{
-	void *sret;
-
-	errno = 0;
-	sret = (void *) syscall(__NR_mmap, addr, len, prot,
-		flags, fd, offset);
-	return sret;
-}
-
 static int sys_munmap(void *ptr, size_t size)
 {
 	int sret;
@@ -172,7 +161,7 @@ static void setup_single_address(int size, void **ptrOut)
 {
 	void *ptr;
 
-	ptr = sys_mmap(NULL, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	ptr = mmap(NULL, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	*ptrOut = ptr;
 }
 
@@ -181,7 +170,7 @@ static void setup_single_address_rw(int size, void **ptrOut)
 	void *ptr;
 	unsigned long mapflags = MAP_ANONYMOUS | MAP_PRIVATE;
 
-	ptr = sys_mmap(NULL, size, PROT_READ | PROT_WRITE, mapflags, -1, 0);
+	ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, mapflags, -1, 0);
 	*ptrOut = ptr;
 }
 
@@ -205,7 +194,7 @@ bool seal_support(void)
 	void *ptr;
 	unsigned long page_size = getpagesize();
 
-	ptr = sys_mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	ptr = mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (ptr == (void *) -1)
 		return false;
 
@@ -481,8 +470,8 @@ static void test_seal_zero_address(void)
 	int prot;
 
 	/* use mmap to change protection. */
-	ptr = sys_mmap(0, size, PROT_NONE,
-			MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+	ptr = mmap(0, size, PROT_NONE,
+		   MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
 	FAIL_TEST_IF_FALSE(ptr == 0);
 
 	size = get_vma_size(ptr, &prot);
@@ -1209,8 +1198,8 @@ static void test_seal_mmap_overwrite_prot(bool seal)
 	}
 
 	/* use mmap to change protection. */
-	ret2 = sys_mmap(ptr, size, PROT_NONE,
-			MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+	ret2 = mmap(ptr, size, PROT_NONE,
+		    MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
 	if (seal) {
 		FAIL_TEST_IF_FALSE(ret2 == MAP_FAILED);
 		FAIL_TEST_IF_FALSE(errno == EPERM);
@@ -1240,8 +1229,8 @@ static void test_seal_mmap_expand(bool seal)
 	}
 
 	/* use mmap to expand. */
-	ret2 = sys_mmap(ptr, size, PROT_READ,
-			MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+	ret2 = mmap(ptr, size, PROT_READ,
+		    MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
 	if (seal) {
 		FAIL_TEST_IF_FALSE(ret2 == MAP_FAILED);
 		FAIL_TEST_IF_FALSE(errno == EPERM);
@@ -1268,8 +1257,8 @@ static void test_seal_mmap_shrink(bool seal)
 	}
 
 	/* use mmap to shrink. */
-	ret2 = sys_mmap(ptr, 8 * page_size, PROT_READ,
-			MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+	ret2 = mmap(ptr, 8 * page_size, PROT_READ,
+		    MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
 	if (seal) {
 		FAIL_TEST_IF_FALSE(ret2 == MAP_FAILED);
 		FAIL_TEST_IF_FALSE(errno == EPERM);
@@ -1650,7 +1639,7 @@ static void test_seal_discard_ro_anon_on_filebacked(bool seal)
 	ret = fallocate(fd, 0, 0, size);
 	FAIL_TEST_IF_FALSE(!ret);
 
-	ptr = sys_mmap(NULL, size, PROT_READ, mapflags, fd, 0);
+	ptr = mmap(NULL, size, PROT_READ, mapflags, fd, 0);
 	FAIL_TEST_IF_FALSE(ptr != MAP_FAILED);
 
 	if (seal) {
@@ -1680,7 +1669,7 @@ static void test_seal_discard_ro_anon_on_shared(bool seal)
 	int ret;
 	unsigned long mapflags = MAP_ANONYMOUS | MAP_SHARED;
 
-	ptr = sys_mmap(NULL, size, PROT_READ, mapflags, -1, 0);
+	ptr = mmap(NULL, size, PROT_READ, mapflags, -1, 0);
 	FAIL_TEST_IF_FALSE(ptr != (void *)-1);
 
 	if (seal) {

tools/testing/selftests/mm/seal_elf.c

@@ -30,17 +30,6 @@ static int sys_mseal(void *start, size_t len)
 	return sret;
 }
 
-static void *sys_mmap(void *addr, unsigned long len, unsigned long prot,
-	unsigned long flags, unsigned long fd, unsigned long offset)
-{
-	void *sret;
-
-	errno = 0;
-	sret = (void *) syscall(__NR_mmap, addr, len, prot,
-		flags, fd, offset);
-	return sret;
-}
-
 static inline int sys_mprotect(void *ptr, size_t size, unsigned long prot)
 {
 	int sret;
@@ -56,7 +45,7 @@ static bool seal_support(void)
 	void *ptr;
 	unsigned long page_size = getpagesize();
 
-	ptr = sys_mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	ptr = mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 	if (ptr == (void *) -1)
 		return false;