From c7142aead87aa5026e4b57671c7dbb1706b02606 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Mon, 12 Dec 2016 16:43:09 -0800
Subject: [PATCH] mm/pkeys: generate pkey system call code only if
ARCH_HAS_PKEYS is selected
Having code for the pkey_mprotect, pkey_alloc and pkey_free system calls
makes only sense if ARCH_HAS_PKEYS is selected. If not selected these
system calls will always return -ENOSPC or -EINVAL.
To simplify things and have less code generate the pkey system call code
only if ARCH_HAS_PKEYS is selected.
For architectures which have already wired up the system calls, but do
not select ARCH_HAS_PKEYS this will result in less generated code and a
different return code: the three system calls will now always return
-ENOSYS, using the cond_syscall mechanism.
For architectures which have not wired up the system calls less
unreachable code will be generated.
Link: http://lkml.kernel.org/r/20161114111251.70084-1-heiko.carstens@de.ibm.com
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/mprotect.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/mprotect.c b/mm/mprotect.c
index c5ba2aae0f542..cc2459c57f608 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -497,6 +497,8 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
return do_mprotect_pkey(start, len, prot, -1);
}
+#ifdef CONFIG_ARCH_HAS_PKEYS
+
SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
unsigned long, prot, int, pkey)
{
@@ -547,3 +549,5 @@ SYSCALL_DEFINE1(pkey_free, int, pkey)
*/
return ret;
}
+
+#endif /* CONFIG_ARCH_HAS_PKEYS */
--
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