[PATCHv2,13/19] kernel: add ksys_personality()

Message ID 20180601112441.37810-14-mark.rutland@arm.com
State Superseded
Headers show
  • arm64: invoke syscalls with pt_regs
Related show

Commit Message

Mark Rutland June 1, 2018, 11:24 a.m.
Using this helper allows us to avoid the in-kernel call to the
sys_personality() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_personality().

Since ksys_personality is trivial, it is implemented directly in
<linux/syscalls.h>, as we do for ksys_close() and friends.

This helper is necessary to enable conversion of arm64's syscall
handling to use pt_regs wrappers.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Martin <dave.martin@arm.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
 include/linux/syscalls.h | 11 +++++++++++
 1 file changed, 11 insertions(+)



diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 70fcda1a9049..652e166deb64 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -79,6 +79,7 @@  union bpf_attr;
 #include <linux/unistd.h>
 #include <linux/quota.h>
 #include <linux/key.h>
+#include <linux/personality.h>
 #include <trace/syscall.h>
@@ -1268,4 +1269,14 @@  static inline long ksys_truncate(const char __user *pathname, loff_t length)
 	return do_sys_truncate(pathname, length);
+static inline unsigned int ksys_personality(unsigned int personality)
+	unsigned int old = current->personality;
+	if (personality != 0xffffffff)
+		set_personality(personality);
+	return old;