Using this helper allows us to avoid the in-kernel call to the compat_sys_sigaltstack() syscall. This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> --- kernel/signal.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 985c61749bcf..f04466655238 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3573,9 +3573,8 @@ int __save_altstack(stack_t __user *uss, unsigned long sp) } #ifdef CONFIG_COMPAT -COMPAT_SYSCALL_DEFINE2(sigaltstack, - const compat_stack_t __user *, uss_ptr, - compat_stack_t __user *, uoss_ptr) +static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr, + compat_stack_t __user *uoss_ptr) { stack_t uss, uoss; int ret; @@ -3602,9 +3601,16 @@ COMPAT_SYSCALL_DEFINE2(sigaltstack, return ret; } +COMPAT_SYSCALL_DEFINE2(sigaltstack, + const compat_stack_t __user *, uss_ptr, + compat_stack_t __user *, uoss_ptr) +{ + return do_compat_sigaltstack(uss_ptr, uoss_ptr); +} + int compat_restore_altstack(const compat_stack_t __user *uss) { - int err = compat_sys_sigaltstack(uss, NULL); + int err = do_compat_sigaltstack(uss, NULL); /* squash all but -EFAULT for now */ return err == -EFAULT ? err : 0; } -- 2.16.3
