On Mon, May 14, 2018 at 10:46:34AM +0100, Mark Rutland wrote:
> 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().
>
> This is necessary to enable conversion of arm64's syscall handling to
> use pt_regs wrappers.
>
> Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>
> ---
> include/linux/syscalls.h | 1 +
> kernel/exec_domain.c | 7 ++++++-
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 70fcda1a9049..6723ea51ec99 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -1148,6 +1148,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
> unsigned long prot, unsigned long flags,
> unsigned long fd, unsigned long pgoff);
> ssize_t ksys_readahead(int fd, loff_t offset, size_t count);
> +unsigned int ksys_personality(unsigned int personality);
>
> /*
> * The following kernel syscall equivalents are just wrappers to fs-internal
> diff --git a/kernel/exec_domain.c b/kernel/exec_domain.c
> index a5697119290e..4ba2b404cba2 100644
> --- a/kernel/exec_domain.c
> +++ b/kernel/exec_domain.c
> @@ -47,7 +47,7 @@ static int __init proc_execdomains_init(void)
> module_init(proc_execdomains_init);
> #endif
>
> -SYSCALL_DEFINE1(personality, unsigned int, personality)
> +unsigned int ksys_personality(unsigned int personality)
> {
> unsigned int old = current->personality;
>
> @@ -56,3 +56,8 @@ SYSCALL_DEFINE1(personality, unsigned int, personality)
>
> return old;
> }
> +
> +SYSCALL_DEFINE1(personality, unsigned int, personality)
> +{
> + return ksys_personality(personality);
> +}
> --
> 2.11.0
>
>
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