[PATCH] linux: Also check pkey_get for ENOSYS on tst-pkey (BZ 31996)

[Yury Khrustalev]

From: Adhemerval Zanella <adhemerval.zanella@linaro.org>

The powerpc pkey_get/pkey_set support was only added for 64-bit [1],
and tst-pkey only checks if the support was present with pkey_alloc
(which does not fail on powerpc32, at least running a 64-bit kernel).

Checked on powerpc-linux-gnu.

[1] https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a803367bab167f5ec4fde1f0d0ec447707c29520
Reviewed-By: Andreas K. Huettel <dilfridge@gentoo.org>

(cherry picked from commit 6b7e2e1d6139b1fb61b911ab897a956042bf7f89)

---

* Adhemerval

Would you be OK with backporting this from 2.40 into 2.39?

---
 sysdeps/unix/sysv/linux/tst-pkey.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sysdeps/unix/sysv/linux/tst-pkey.c b/sysdeps/unix/sysv/linux/tst-pkey.c
index d9083daab9..46f55666da 100644
--- a/sysdeps/unix/sysv/linux/tst-pkey.c
+++ b/sysdeps/unix/sysv/linux/tst-pkey.c
@@ -205,7 +205,13 @@ do_test (void)
            " protection keys");
       FAIL_EXIT1 ("pkey_alloc: %m");
     }
-  TEST_COMPARE (pkey_get (keys[0]), 0);
+  if (pkey_get (keys[0]) < 0)
+    {
+      if (errno == ENOSYS)
+	FAIL_UNSUPPORTED
+	  ("glibc does not support memory protection keys");
+      FAIL_EXIT1 ("pkey_alloc: %m");
+    }
   for (int i = 1; i < key_count; ++i)
     {
       keys[i] = pkey_alloc (0, i);
-- 
2.47.3