Re: [PATCH] selftests: mm: Fix build errors on armhf

Hi Muhammad

On Fri, Aug 9, 2024 at 1:25 AM Muhammad Usama Anjum usama.anjum@collabora.com wrote:

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

The mseal_test should't have dependency on libc, and mmap() is implemented by glibc, right ?

I just fixed a bug to switch mremap() to sys_mremap to address an issue that different glibc version's behavior is slightly different for mremap().

What is the reason that __NR_mmap not available in armhf ? (maybe it is another name ?) there must be a way to call syscall directly on armhf, can we use that instead ?

Thanks -Jeff

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, | ^~~~~~~~~

Cc: stable@vger.kernel.org Fixes: 4926c7a52de7 ("selftest mm/mseal memory sealing") Signed-off-by: Muhammad Usama Anjum usama.anjum@collabora.com

---

tools/testing/selftests/mm/mseal_test.c | 37 +++++++++---------------- tools/testing/selftests/mm/seal_elf.c | 13 +-------- 2 files changed, 14 insertions(+), 36 deletions(-)

diff --git a/tools/testing/selftests/mm/mseal_test.c b/tools/testing/selftests/mm/mseal_test.c index a818f010de479..bfcea5cf9a484 100644 --- a/tools/testing/selftests/mm/mseal_test.c +++ b/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) {
  

diff --git a/tools/testing/selftests/mm/seal_elf.c b/tools/testing/selftests/mm/seal_elf.c index 7aa1366063e4e..d9f8ba8d5050b 100644 --- a/tools/testing/selftests/mm/seal_elf.c +++ b/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;
  
  

-- 2.39.2