[PATCH] selftests/powerpc: use MAP_FAILED instead of (void *)-1 in tm-signal-context-force-tm

mmap() is documented to return MAP_FAILED on error, but
tm-signal-context-force-tm.c compares the return value against
(void *)-1. Replace these with the standard MAP_FAILED macro for
better readability and type safety.

Signed-off-by: longlong yan <redacted>
---
 .../testing/selftests/powerpc/tm/tm-signal-context-force-tm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c b/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
index 0a4bc479ae39..5dc0f12f467d 100644
--- a/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c

@@ -60,7 +60,7 @@ void usr_signal_handler(int signo, siginfo_t *si, void *uc)
 	ucp->uc_link = mmap(NULL, sizeof(ucontext_t),
 			    PROT_READ | PROT_WRITE,
 			    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
-	if (ucp->uc_link == (void *)-1) {
+	if (ucp->uc_link == MAP_FAILED) {
 		perror("Mmap failed");
 		exit(-1);
 	}

@@ -129,7 +129,7 @@ void tm_trap_test(void)
 		ss.ss_size = SIGSTKSZ;
 		ss.ss_flags = 0;
 
-		if (ss.ss_sp == (void *)-1) {
+		if (ss.ss_sp == MAP_FAILED) {
 			perror("mmap error\n");
 			exit(-1);
 		}

-- 
2.43.0

On 2026/07/22 10:34 AM, longlong yan wrote:

mmap() is documented to return MAP_FAILED on error, but
tm-signal-context-force-tm.c compares the return value against
(void *)-1. Replace these with the standard MAP_FAILED macro for
better readability and type safety.

The mmap man page does confirm:

  RETURN VALUE
         On success, mmap() returns a pointer to the mapped area.  On
         error, the value MAP_FAILED (that is, (void *) -1) is returned,
         and errno is set to indicate the error.

So, the MAP_FAILED substitution looks correct. Please feel free to add:

Reviewed-by: Amit Machhiwal <redacted>

Thanks,
Amit

On 22 Jul 2026, at 8:04 AM, longlong yan [off-list ref] wrote:

mmap() is documented to return MAP_FAILED on error, but
tm-signal-context-force-tm.c compares the return value against
(void *)-1. Replace these with the standard MAP_FAILED macro for
better readability and type safety.

Signed-off-by: longlong yan <redacted>
---

Tested this patch, by applying on top of mainline.

Tested-by: Venkat Rao Bagalkote <redacted>

# timeout set to 0
# selftests: powerpc/tm: tm-signal-context-force-tm
# test: tm_signal_context_force_tm
# tags: git_version:v7.3-rc2-28-g5572a2d442d5
# success: tm_signal_context_force_tm
ok 18 selftests: powerpc/tm: tm-signal-context-force-tm

Regards,
Venkat.

On Wed, 22 Jul 2026 10:34:28 +0800, longlong yan wrote:

mmap() is documented to return MAP_FAILED on error, but
tm-signal-context-force-tm.c compares the return value against
(void *)-1. Replace these with the standard MAP_FAILED macro for
better readability and type safety.

Applied to powerpc/fixes.

[1/1] selftests/powerpc: use MAP_FAILED instead of (void *)-1 in tm-signal-context-force-tm
      https://git.kernel.org/powerpc/c/bf1d8287816194457c1a936056ad2d1e1e478944

cheers