Commit c7142aea authored Dec 12, 2016 by Heiko Carstens Committed by Linus Torvalds Dec 12, 2016

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>

parent c3352cbb

mm/mprotect.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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 */