Commit bf1c77b4 authored Jul 11, 2018 by Mark Rutland Committed by Will Deacon Jul 12, 2018

kernel: add ksys_personality()



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>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Martin <dave.martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent 80d63bc3

include/linux/syscalls.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -80,6 +80,7 @@ union bpf_attr;
		#include <linux/unistd.h>
		#include <linux/quota.h>
		#include <linux/key.h>
		#include <linux/personality.h>
		#include <trace/syscall.h>

		#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
		@@ -1281,4 +1282,14 @@ 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;
		}

		#endif