alpha: Use Linux generic sigaction implementation

Alpha rt_sigaction syscall uses a slight different kernel ABI than
generic one:

arch/alpha/kernel/signal.c

 90 SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act,
 91                 struct sigaction __user *, oact,
 92                 size_t, sigsetsize, void __user *, restorer)

Similar as sparc, the syscall expects a restorer function.  However
different than sparc, alpha defines the restorer as the 5th argument
(sparc defines as the 4th).

This patch removes the arch-specific alpha sigaction implementation,
adapt the Linux generic one to different restore placements (through
STUB macro), and make alpha use the Linux generic kernel_sigaction
definition.

Checked on alpha-linux-gnu and x86_64-linux-gnu (for sanity).

	* sysdeps/unix/sysv/linux/alpha/Makefile: Update comment about
	__syscall_rt_sigaction.
	* sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
	(kernel_sigaction): Use Linux generic defintion.
	(STUB): Define.
	(__syscall_rt_sigreturn, __syscall_sigreturn): Add prototype.
	* sysdeps/unix/sysv/linux/alpha/rt_sigaction.S
	(__syscall_rt_sigaction): Remove implementation.
	(__syscall_sigreturn, __syscall_rt_sigreturn): Define as global and
	hidden.
	* sysdeps/unix/sysv/linux/alpha/sigaction.c: Remove file.
	* sysdeps/unix/sysv/linux/alpha/sysdep.h (INLINE_SYSCALL,
	INTERNAL_SYSCALL): Remove definitions.
	* sysdeps/unix/sysv/linux/sigaction.c: Define STUB to accept both the
	action and signal set size.
	* sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c (STUB): Redefine.
	* sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c (STUB): Likewise.

5 files changed, 14 insertions, 109 deletions

diff --git a/sysdeps/unix/sysv/linux/alpha/Makefile b/sysdeps/unix/sysv/linux/alpha/Makefile
index 50f4fb1183..fdd089af71 100644
--- a/sysdeps/unix/sysv/linux/alpha/Makefile
+++ b/sysdeps/unix/sysv/linux/alpha/Makefile
@@ -31,7 +31,7 @@ libm-routines += multc3 divtc3
 endif   # math
 
 ifeq ($(subdir),nptl)
-# pull in __syscall_error routine, __sigprocmask, __syscall_rt_sigaction
+# pull in __syscall_error routine, __sigprocmask, sigaction stubs.
 libpthread-routines += sysdep sigprocmask rt_sigaction
 libpthread-shared-only-routines += sysdep sigprocmask rt_sigaction
 endif
diff --git a/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h b/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
index 25180ff9c9..679179b563 100644
--- a/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
+++ b/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
@@ -1,12 +1,11 @@
-#ifndef _KERNEL_SIGACTION_H
-# define _KERNEL_SIGACTION_H
+#include <sysdeps/unix/sysv/linux/kernel_sigaction.h>
 
-/* This is the sigaction structure from the Linux 3.2 kernel.  */
-struct kernel_sigaction
-{
-  __sighandler_t k_sa_handler;
-  unsigned int sa_flags;
-  sigset_t sa_mask;
-};
+void __syscall_rt_sigreturn (void) attribute_hidden;
+void __syscall_sigreturn (void) attribute_hidden;
 
-#endif
+#define STUB(act, sigsetsize) \
+  (sigsetsize),						\
+  (act) ? ((unsigned long)((act->sa_flags & SA_SIGINFO)	\
+			    ? &__syscall_rt_sigreturn	\
+			    : &__syscall_sigreturn))	\
+	: 0
diff --git a/sysdeps/unix/sysv/linux/alpha/rt_sigaction.S b/sysdeps/unix/sysv/linux/alpha/rt_sigaction.S
index ca25eee611..17e55239fe 100644
--- a/sysdeps/unix/sysv/linux/alpha/rt_sigaction.S
+++ b/sysdeps/unix/sysv/linux/alpha/rt_sigaction.S
@@ -18,43 +18,6 @@
 
 #include <sysdep.h>
 
-/* On Alpha we desparately want to avoid having to issue an imb.  Ordinarily
-   the kernel would have to issue one after setting up the signal return
-   stack, but the Linux rt_sigaction syscall is prepared to accept a pointer
-   to the sigreturn syscall, instead of inlining it on the stack.
-
-   This just about halves signal delivery time.  */
-
-	.text
-
-ENTRY(__syscall_rt_sigaction)
-	cfi_startproc
-	ldgp	gp,0(pv)
-#ifdef PROF
-	.set noat
-	lda	AT, _mcount
-	jsr	AT, (AT), _mcount
-	.set at
-#endif
-	.prologue 1
-
-	beq	a1, 0f
-	ldl	t0, 8(a1)				# sa_flags
-
-	ldah	a4, __syscall_sigreturn(gp)		!gprelhigh
-	ldah	t1, __syscall_rt_sigreturn(gp)		!gprelhigh
-	lda	a4, __syscall_sigreturn(a4)		!gprellow
-	lda	t1, __syscall_rt_sigreturn(t1)		!gprellow
-	and	t0, 0x40, t0				# SA_SIGINFO
-	cmovne	t0, t1, a4
-
-0:	ldi	v0, __NR_rt_sigaction
-	callsys
-	bne	a3, SYSCALL_ERROR_LABEL
-	ret
-	cfi_endproc
-PSEUDO_END(__syscall_rt_sigaction)
-
 /* To enable unwinding through the signal frame without special hackery
    elsewhere, describe the entire struct sigcontext with unwind info.
 
@@ -104,6 +67,8 @@ __syscall_sigreturn:
 	callsys
 	.size	__syscall_sigreturn, .-__syscall_sigreturn
 	.type	__syscall_sigreturn, @function
+	.global __syscall_sigreturn;
+	.hidden __syscall_sigreturn;
 
 	/* See above wrt including the nop.  */
 	cfi_def_cfa_offset (176 + 648)
@@ -116,5 +81,7 @@ __syscall_rt_sigreturn:
 	callsys
 	.size	__syscall_rt_sigreturn, .-__syscall_rt_sigreturn
 	.type	__syscall_rt_sigreturn, @function
+	.global __syscall_rt_sigreturn;
+	.hidden __syscall_rt_sigreturn;
 
 	cfi_endproc
diff --git a/sysdeps/unix/sysv/linux/alpha/sigaction.c b/sysdeps/unix/sysv/linux/alpha/sigaction.c
deleted file mode 100644
index 8051043587..0000000000
--- a/sysdeps/unix/sysv/linux/alpha/sigaction.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/* Copyright (C) 2003-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library.  If not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#include <sysdep.h>
-#include <sys/cdefs.h>
-#include <stddef.h>
-
-/*
- * In order to get the hidden arguments for rt_sigaction set up
- * properly, we need to call the assembly version.  Detect this in the
- * INLINE_SYSCALL macro, and fail to expand inline in that case.
- */
-
-#undef INLINE_SYSCALL
-#define INLINE_SYSCALL(name, nr, args...)       \
-        (__NR_##name == __NR_rt_sigaction       \
-         ? __syscall_rt_sigaction(args)         \
-         : INLINE_SYSCALL1(name, nr, args))
-
-struct kernel_sigaction;
-extern int __syscall_rt_sigaction (int, const struct kernel_sigaction *,
-				   struct kernel_sigaction *, size_t);
-
-#include <sysdeps/unix/sysv/linux/sigaction.c>
diff --git a/sysdeps/unix/sysv/linux/alpha/sysdep.h b/sysdeps/unix/sysv/linux/alpha/sysdep.h
index 080405021f..9148b4793b 100644
--- a/sysdeps/unix/sysv/linux/alpha/sysdep.h
+++ b/sysdeps/unix/sysv/linux/alpha/sysdep.h
@@ -72,27 +72,4 @@
 
 #define SINGLE_THREAD_BY_GLOBAL 1
 
-/*
- * In order to get the hidden arguments for rt_sigaction set up
- * properly, we need to call the assembly version.  This shouldn't
- * happen except for inside sigaction.c, where we handle this
- * specially.  Catch other uses and error.
- */
-
-#undef INLINE_SYSCALL
-#define INLINE_SYSCALL(name, nr, args...)				\
-({									\
-	extern char ChEcK[__NR_##name == __NR_rt_sigaction ? -1 : 1]	\
-	  __attribute__((unused));					\
-	INLINE_SYSCALL1(name, nr, args);				\
-})
-
-#undef INTERNAL_SYSCALL
-#define INTERNAL_SYSCALL(name, err_out, nr, args...)			\
-({									\
-	extern char ChEcK[__NR_##name == __NR_rt_sigaction ? -1 : 1]	\
-	  __attribute__((unused));					\
-	INTERNAL_SYSCALL1(name, err_out, nr, args);			\
-})
-
 #endif /* _LINUX_ALPHA_SYSDEP_H */