linux: Consolidate sigaction implementation

This patch consolidates all Linux sigaction implementations on the default
sysdeps/unix/sysv/linux/sigaction.c.  The idea is remove redundant code
and simplify new ports addition by following the current generic
Linux User API (UAPI).

The UAPI for new ports defines a generic extensible sigaction struct as:

  struct sigaction
  {
    __sighandler_t sa_handler;
    unsigned long sa_flags;
  #ifdef SA_RESTORER
    void (*sa_restorer) (void);
  #endif
    sigset_t sa_mask;
  };

Where SA_RESTORER is just placed for compatibility reasons (news ports
should not add it).  A similar definition is used on generic
kernel_sigaction.h.

The user exported sigaction definition is not changed, so for most
architectures it requires an adjustment to kernel expected one for the
syscall.

The main changes are:

  - All architectures now define and use a kernel_sigaction struct meant
    for the syscall, even for the architectures where the user sigaction
    has the same layout of the kernel expected one (s390-64 and ia64).
    Although it requires more work for these architectures, it simplifies
    the generic implementation. Also, sigaction is hardly a hotspot where
    micro optimization would play an important role.

  - The generic kernel_sigaction definition is now aligned with expected
    UAPI one for newer ports, where SA_RESTORER and sa_restorer are not
    expected to be defined.  This means adding kernel_sigaction for
    current architectures that does define it (m68k, nios2, powerpc, s390,
    sh, sparc, and tile) and which rely on previous generic definition.

  - Remove old MIPS usage of sa_restorer.  This was removed since 2.6.27
    (2957c9e61ee9c - "[MIPS] IRIX: Goodbye and thanks for all the fish").

  - The remaining arch-specific sigaction.c are to handle ABI idiosyncrasies
    (like SPARC kernel ABI for rt_sigaction that requires an additional
    stub argument).

So for new ports the generic implementation should work if its uses
Linux UAPI.  If SA_RESTORER is still required (due some architecture
limitation), it should define its own kernel_sigaction.h, define it and
include generic header (assuming it still uses the default generic kernel
layout).

Checked on x86_64-linux-gnu, i686-linux-gnu, arm-linux-gnueabihf,
aarch64-linux-gnu, sparc64-linux-gnu, sparcv9-linux-gnu, powerpc-linux-gnu,
powerpc64-linux-gnu, ia64-linux-gnu and alpha-linux-gnu.  I also checked the
build on all remaining affected ABIs.

	* sysdeps/unix/sysv/linux/aarch64/sigaction.c: Use default Linux version
	as base implementation.
	* sysdeps/unix/sysv/linux/arm/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h: Add include guards,
	remove unrequired definitions and update comments.
	* sysdeps/unix/sysv/linux/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/mips/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/ia64/kernel_sigaction.h: New file.
	* sysdeps/unix/sysv/linux/m68k/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/nios2/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/kernel_sigaction: Likewise.
	* sysdeps/unix/sysv/linux/s390/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/sh/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/sparc/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/tile/kernel_sigaction.h: Likewise.
	* sysdeps/unix/sysv/linux/ia64/sigaction.c: Remove file.
	* sysdeps/unix/sysv/linux/mips/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/sigaction.c: Likewise.
	* sysdeps/unix/sysv/linux/sigaction.c: Add STUB, SET_SA_RESTORER,
	and RESET_SA_RESTORER hooks.

22 files changed, 237 insertions, 585 deletions

diff --git a/ChangeLog b/ChangeLog
index 17506be6a9..e7abee53e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,30 @@
+2018-04-05 Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+
+	* sysdeps/unix/sysv/linux/aarch64/sigaction.c: Use default Linux version
+	as base implementation.
+	* sysdeps/unix/sysv/linux/arm/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/i386/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h: Add include guards,
+	remove unrequired definitions and update comments.
+	* sysdeps/unix/sysv/linux/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/mips/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/ia64/kernel_sigaction.h: New file.
+	* sysdeps/unix/sysv/linux/m68k/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/nios2/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/kernel_sigaction: Likewise.
+	* sysdeps/unix/sysv/linux/s390/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/sh/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/sparc/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/tile/kernel_sigaction.h: Likewise.
+	* sysdeps/unix/sysv/linux/ia64/sigaction.c: Remove file.
+	* sysdeps/unix/sysv/linux/mips/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/s390/s390-64/sigaction.c: Likewise.
+	* sysdeps/unix/sysv/linux/sigaction.c: Add STUB, SET_SA_RESTORER,
+	and RESET_SA_RESTORER hooks.
+
 2018-04-05  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
 	* sysdeps/s390/fpu/libm-test-ulps: Regenerated.
diff --git a/sysdeps/unix/sysv/linux/aarch64/sigaction.c b/sysdeps/unix/sysv/linux/aarch64/sigaction.c
index 73f4eb79fc..fef195eefb 100644
--- a/sysdeps/unix/sysv/linux/aarch64/sigaction.c
+++ b/sysdeps/unix/sysv/linux/aarch64/sigaction.c
@@ -1,5 +1,4 @@
 /* Copyright (C) 1997-2018 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
@@ -16,55 +15,16 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
+/* Required for AArch32 compatibility. */
 #define SA_RESTORER	0x04000000
 
-/* The difference here is that the sigaction structure used in the
-   kernel is not the same as we use in the libc.  Therefore we must
-   translate it here.  */
-#include <kernel_sigaction.h>
-
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  int result;
-  struct kernel_sigaction kact;
-  struct kernel_sigaction koact;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
-      kact.sa_flags = act->sa_flags;
-#ifdef HAVE_SA_RESTORER
-      if (kact.sa_flags & SA_RESTORER)
-	kact.sa_restorer = act->sa_restorer;
-#endif
-    }
+#define SET_SA_RESTORER(kact, act)		\
+ ({						\
+    if ((kact)->sa_flags & SA_RESTORER)		\
+      (kact)->sa_restorer = (act)->sa_restorer;	\
+ })
 
-  result = INLINE_SYSCALL (rt_sigaction, 4, sig,
-			   act ? &kact : NULL,
-			   oact ? &koact : NULL, _NSIG / 8);
-  if (result >= 0 || errno != ENOSYS)
-    {
-      if (oact && result >= 0)
-	{
-	  oact->sa_handler = koact.k_sa_handler;
-	  memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
-	  oact->sa_flags = koact.sa_flags;
-#ifdef HAVE_SA_RESTORER
-	  oact->sa_restorer = koact.sa_restorer;
-#endif
-	}
-    }
-  return result;
-}
-libc_hidden_def (__libc_sigaction)
+#define RESET_SA_RESTORER(act, kact)		\
+  (act)->sa_restorer = (kact)->sa_restorer;
 
-#include <nptl/sigaction.c>
+#include <sysdeps/unix/sysv/linux/sigaction.c>
diff --git a/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h b/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
index 4c35d969cf..25180ff9c9 100644
--- a/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
+++ b/sysdeps/unix/sysv/linux/alpha/kernel_sigaction.h
@@ -1,15 +1,12 @@
-/* This is the sigaction struction from the Linux 2.1.20 kernel.  */
+#ifndef _KERNEL_SIGACTION_H
+# define _KERNEL_SIGACTION_H
 
-struct old_kernel_sigaction {
-	__sighandler_t k_sa_handler;
-	unsigned long sa_mask;
-	unsigned int sa_flags;
+/* 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;
 };
 
-/* This is the sigaction structure from the Linux 2.1.68 kernel.  */
-
-struct kernel_sigaction {
-	__sighandler_t k_sa_handler;
-	unsigned int sa_flags;
-	sigset_t sa_mask;
-};
+#endif
diff --git a/sysdeps/unix/sysv/linux/arm/sigaction.c b/sysdeps/unix/sysv/linux/arm/sigaction.c
index e4d80de10d..c828250815 100644
--- a/sysdeps/unix/sysv/linux/arm/sigaction.c
+++ b/sysdeps/unix/sysv/linux/arm/sigaction.c
@@ -15,70 +15,25 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* The difference here is that the sigaction structure used in the
-   kernel is not the same as we use in the libc.  Therefore we must
-   translate it here.  */
-#include <kernel_sigaction.h>
-
 #define SA_RESTORER	0x04000000
 
 extern void __default_sa_restorer (void);
 extern void __default_rt_sa_restorer (void);
 
-/* When RT signals are in use we need to use a different return stub.  */
-#define choose_restorer(flags)					\
-  (flags & SA_SIGINFO) ? __default_rt_sa_restorer		\
-  : __default_sa_restorer
-
-/* If ACT is not NULL, change the action for SIG to *ACT.
-   If OACT is not NULL, put the old action for SIG in *OACT.  */
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  int result;
-
-  struct kernel_sigaction kact, koact;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
-      kact.sa_flags = act->sa_flags;
-#ifdef HAVE_SA_RESTORER
-      if (kact.sa_flags & SA_RESTORER)
-	kact.sa_restorer = act->sa_restorer;
-      else
-	{
-	  kact.sa_restorer = choose_restorer (kact.sa_flags);
-	  kact.sa_flags |= SA_RESTORER;
-	}
-#endif
-    }
-
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  result = INLINE_SYSCALL (rt_sigaction, 4, sig,
-			   act ? &kact : NULL,
-			   oact ? &koact : NULL, _NSIG / 8);
-
-  if (oact && result >= 0)
-    {
-      oact->sa_handler = koact.k_sa_handler;
-      memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
-      oact->sa_flags = koact.sa_flags;
-#ifdef HAVE_SA_RESTORER
-      oact->sa_restorer = koact.sa_restorer;
-#endif
-    }
-  return result;
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
+#define SET_SA_RESTORER(kact, act)				\
+ ({								\
+   if ((kact)->sa_flags & SA_RESTORER)				\
+     (kact)->sa_restorer = (act)->sa_restorer;			\
+   else								\
+     {								\
+       (kact)->sa_restorer = ((kact)->sa_flags & SA_SIGINFO)	\
+			     ? __default_rt_sa_restorer		\
+			     : __default_sa_restorer;		\
+       (kact)->sa_flags |= SA_RESTORER;				\
+     }								\
+ })
+
+#define RESET_SA_RESTORER(act, kact)				\
+  (act)->sa_restorer = (kact)->sa_restorer;
+
+#include <sysdeps/unix/sysv/linux/sigaction.c>
diff --git a/sysdeps/unix/sysv/linux/i386/sigaction.c b/sysdeps/unix/sysv/linux/i386/sigaction.c
index 177ff60ee6..df9fa0ca5b 100644
--- a/sysdeps/unix/sysv/linux/i386/sigaction.c
+++ b/sysdeps/unix/sysv/linux/i386/sigaction.c
@@ -16,79 +16,30 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <sysdep.h>
-#include <errno.h>
-#include <stddef.h>
 #include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
 #include <ldsodefs.h>
 
-/* The difference here is that the sigaction structure used in the
-   kernel is not the same as we use in the libc.  Therefore we must
-   translate it here.  */
-#include <kernel_sigaction.h>
-
-/* We do not globally define the SA_RESTORER flag so do it here.  */
 #define SA_RESTORER 0x04000000
 
-
-/* Using the hidden attribute here does not change the code but it
-   helps to avoid warnings.  */
-#ifdef __NR_rt_sigaction
 extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;
-#endif
 extern void restore (void) asm ("__restore") attribute_hidden;
 
-/* If ACT is not NULL, change the action for SIG to *ACT.
-   If OACT is not NULL, put the old action for SIG in *OACT.  */
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  int result;
-
-  struct kernel_sigaction kact, koact;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      kact.sa_flags = act->sa_flags;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
-
-      if (GLRO(dl_sysinfo_dso) == NULL)
-	{
-	  kact.sa_flags |= SA_RESTORER;
-
-	  kact.sa_restorer = ((act->sa_flags & SA_SIGINFO)
-			      ? &restore_rt : &restore);
-	}
-      else
-	kact.sa_restorer = NULL;
-    }
+#define SET_SA_RESTORER(kact, act)				\
+  ({								\
+     if (GLRO(dl_sysinfo_dso) == NULL)				\
+       {							\
+	 (kact)->sa_flags |= SA_RESTORER;			\
+         (kact)->sa_restorer = (((act)->sa_flags & SA_SIGINFO)	\
+			       ? &restore_rt : &restore);	\
+       }							\
+     else							\
+       (kact)->sa_restorer = NULL;				\
+  })
 
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  INTERNAL_SYSCALL_DECL (err);
-  result = INTERNAL_SYSCALL (rt_sigaction, err, 4,
-			     sig, act ? &kact : NULL,
-			     oact ? &koact : NULL, _NSIG / 8);
-  if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
-     return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result,
-								       err));
-  else if (oact && result >= 0)
-    {
-      oact->sa_handler = koact.k_sa_handler;
-      memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
-      oact->sa_flags = koact.sa_flags;
-      oact->sa_restorer = koact.sa_restorer;
-    }
-  return result;
-}
-libc_hidden_def (__libc_sigaction)
+#define RESET_SA_RESTORER(act, kact) \
+  (act)->sa_restorer = (kact)->sa_restorer
 
-#include <nptl/sigaction.c>
+#include <sysdeps/unix/sysv/linux/sigaction.c>
 
 /* NOTE: Please think twice before making any changes to the bits of
    code below.  GDB needs some intimate knowledge about it to
@@ -109,10 +60,8 @@ asm						\
    "	int  $0x80"				\
    );
 
-#ifdef __NR_rt_sigaction
 /* The return code for realtime-signals.  */
 RESTORE (restore_rt, __NR_rt_sigreturn)
-#endif
 
 /* For the boring old signals.  */
 #undef RESTORE2
diff --git a/sysdeps/unix/sysv/linux/ia64/kernel_sigaction.h b/sysdeps/unix/sysv/linux/ia64/kernel_sigaction.h
new file mode 100644
index 0000000000..fc9f29603c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/ia64/kernel_sigaction.h
@@ -0,0 +1,7 @@
+/* This is the sigaction structure from the Linux 3.2 kernel.  */
+struct kernel_sigaction
+{
+  __sighandler_t k_sa_handler;
+  unsigned long sa_flags;
+  sigset_t sa_mask;               /* mask last for extensibility */
+};
diff --git a/sysdeps/unix/sysv/linux/ia64/sigaction.c b/sysdeps/unix/sysv/linux/ia64/sigaction.c
deleted file mode 100644
index e7fb8cd2e0..0000000000
--- a/sysdeps/unix/sysv/linux/ia64/sigaction.c
+++ /dev/null
@@ -1,45 +0,0 @@
-/* Copyright (C) 1997-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Linux/IA64 specific sigaction
-   Written by Jes Sorensen, <Jes.Sorensen@cern.ch>, April 1999.
-
-   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/>.  */
-
-/* Linux/ia64 only has rt signals, thus we do not even want to try falling
-   back to the old style signals as the default Linux handler does. */
-
-#include <errno.h>
-#include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* The variable is shared between all wrappers around signal handling
-   functions which have RT equivalents.  This is the definition.  */
-
-
-/* If ACT is not NULL, change the action for SIG to *ACT.
-   If OACT is not NULL, put the old action for SIG in *OACT.  */
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  return INLINE_SYSCALL (rt_sigaction, 4, sig, act, oact, _NSIG / 8);
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
diff --git a/sysdeps/unix/sysv/linux/kernel_sigaction.h b/sysdeps/unix/sysv/linux/kernel_sigaction.h
index d005cbce98..2dbec08099 100644
--- a/sysdeps/unix/sysv/linux/kernel_sigaction.h
+++ b/sysdeps/unix/sysv/linux/kernel_sigaction.h
@@ -1,19 +1,20 @@
-/* This is the sigaction structure from the Linux 2.1.20 kernel.  */
+#ifndef _KERNEL_SIGACTION_H
+# define _KERNEL_SIGACTION_H
 
-#define HAVE_SA_RESTORER
-
-struct old_kernel_sigaction {
-	__sighandler_t k_sa_handler;
-	unsigned long sa_mask;
-	unsigned long sa_flags;
-	void (*sa_restorer) (void);
+/* This is the sigaction structure from the Linux 3.2 kernel.  */
+struct kernel_sigaction
+{
+  __sighandler_t k_sa_handler;
+  unsigned long sa_flags;
+#ifdef SA_RESTORER
+  void (*sa_restorer) (void);
+#endif
+  sigset_t sa_mask;
 };
 
-/* This is the sigaction structure from the Linux 2.1.68 kernel.  */
+#ifndef SA_RESTORER
+# define SET_SA_RESTORER(kact, act)
+# define RESET_SA_RESTORER(act, kact)
+#endif
 
-struct kernel_sigaction {
-	__sighandler_t k_sa_handler;
-	unsigned long sa_flags;
-	void (*sa_restorer) (void);
-	sigset_t sa_mask;
-};
+#endif
diff --git a/sysdeps/unix/sysv/linux/m68k/kernel_sigaction.h b/sysdeps/unix/sysv/linux/m68k/kernel_sigaction.h
new file mode 100644
index 0000000000..54972feb13
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/m68k/kernel_sigaction.h
@@ -0,0 +1,22 @@
+#ifndef _KERNEL_SIGACTION_H
+# define _KERNEL_SIGACTION_H
+
+#include <signal.h>
+
+#define SA_RESTORER 0x04000000
+
+/* This is the sigaction structure from the Linux 3.2 kernel.  */
+struct kernel_sigaction
+{
+  __sighandler_t k_sa_handler;
+  sigset_t sa_mask;
+  unsigned long sa_flags;
+  void (*sa_restorer) (void);
+};
+
+#define SET_SA_RESTORER(kact, act)			\
+  (kact)->sa_restorer = (act)->sa_restorer
+#define RESET_SA_RESTORER(act, kact)			\
+  (act)->sa_restorer = (kact)->sa_restorer
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/mips/kernel_sigaction.h b/sysdeps/unix/sysv/linux/mips/kernel_sigaction.h
index b6f52cc9c9..beef976cc3 100644
--- a/sysdeps/unix/sysv/linux/mips/kernel_sigaction.h
+++ b/sysdeps/unix/sysv/linux/mips/kernel_sigaction.h
@@ -1,40 +1,12 @@
-/* This is the sigaction structure from the Linux 2.1.24 kernel.  */
-
-#include <sgidefs.h>
-
-#define HAVE_SA_RESTORER
-
-struct old_kernel_sigaction {
-	unsigned int	sa_flags;
-	__sighandler_t	k_sa_handler;
-	unsigned long	sa_mask;
-	unsigned int    __pad0[3]; /* reserved, keep size constant */
-
-	/* Abi says here follows reserved int[2] */
-	void		(*sa_restorer)(void);
-#if (_MIPS_SZPTR < 64)
-	/*
-	 * For 32 bit code we have to pad struct sigaction to get
-	 * constant size for the ABI
-	 */
-	int		pad1[1]; /* reserved */
-#endif
+#ifndef _KERNEL_SIGACTION_H
+# define _KERNEL_SIGACTION_H
+
+/* This is the sigaction structure from the Linux 3.2 kernel.  */
+struct kernel_sigaction
+{
+  unsigned int    sa_flags;
+  __sighandler_t  k_sa_handler;
+  sigset_t        sa_mask;
 };
 
-
-#define _KERNEL_NSIG	       128
-#define _KERNEL_NSIG_BPW       _MIPS_SZLONG
-#define _KERNEL_NSIG_WORDS     (_KERNEL_NSIG / _KERNEL_NSIG_BPW)
-
-typedef struct {
-	unsigned long sig[_KERNEL_NSIG_WORDS];
-} kernel_sigset_t;
-
-/* This is the sigaction structure from the Linux 2.1.68 kernel.  */
-struct kernel_sigaction {
-	unsigned int	sa_flags;
-	__sighandler_t	k_sa_handler;
-	kernel_sigset_t	sa_mask;
-	void		(*sa_restorer)(void);
-	int		s_resv[1]; /* reserved */
-};
+#endif
diff --git a/sysdeps/unix/sysv/linux/mips/sigaction.c b/sysdeps/unix/sysv/linux/mips/sigaction.c
deleted file mode 100644
index 008b688977..0000000000
--- a/sysdeps/unix/sysv/linux/mips/sigaction.c
+++ /dev/null
@@ -1,116 +0,0 @@
-/* Copyright (C) 1997-2018 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 <errno.h>
-#include <sgidefs.h>
-#include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-#include <sgidefs.h>
-
-/* The difference here is that the sigaction structure used in the
-   kernel is not the same as we use in the libc.  Therefore we must
-   translate it here.  */
-#include <kernel_sigaction.h>
-
-#if _MIPS_SIM != _ABIO32
-
-# ifdef __NR_rt_sigreturn
-static void restore_rt (void) asm ("__restore_rt");
-# endif
-# ifdef __NR_sigreturn
-static void restore (void) asm ("__restore");
-# endif
-#endif
-
-/* If ACT is not NULL, change the action for SIG to *ACT.
-   If OACT is not NULL, put the old action for SIG in *OACT.  */
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  int result;
-
-  struct kernel_sigaction kact, koact;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (kernel_sigset_t));
-      kact.sa_flags = act->sa_flags;
-#ifdef HAVE_SA_RESTORER
-# if _MIPS_SIM == _ABIO32
-      kact.sa_restorer = act->sa_restorer;
-# else
-      kact.sa_restorer = &restore_rt;
-# endif
-#endif
-    }
-
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.	*/
-  result = INLINE_SYSCALL (rt_sigaction, 4, sig,
-			   act ? &kact : NULL,
-			   oact ? &koact : NULL,
-			   sizeof (kernel_sigset_t));
-
-  if (oact && result >= 0)
-    {
-      oact->sa_handler = koact.k_sa_handler;
-      memcpy (&oact->sa_mask, &koact.sa_mask,
-	      sizeof (kernel_sigset_t));
-      oact->sa_flags = koact.sa_flags;
-#ifdef HAVE_SA_RESTORER
-      oact->sa_restorer = koact.sa_restorer;
-#endif
-    }
-  return result;
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
-
-
-/* NOTE: Please think twice before making any changes to the bits of
-   code below.  GDB needs some intimate knowledge about it to
-   recognize them as signal trampolines, and make backtraces through
-   signal handlers work right.  Important are both the names
-   (__restore_rt) and the exact instruction sequence.
-   If you ever feel the need to make any changes, please notify the
-   appropriate GDB maintainer.  */
-
-#define RESTORE(name, syscall) RESTORE2 (name, syscall)
-#define RESTORE2(name, syscall) \
-asm						\
-  (						\
-   ".align 4\n"					\
-   "__" #name ":\n"				\
-   "	li $2, " #syscall "\n"			\
-   "	syscall\n"				\
-   );
-
-/* The return code for realtime-signals.  */
-#if _MIPS_SIM != _ABIO32
-# ifdef __NR_rt_sigreturn
-RESTORE (restore_rt, __NR_rt_sigreturn)
-# endif
-# ifdef __NR_sigreturn
-RESTORE (restore, __NR_sigreturn)
-# endif
-#endif
diff --git a/sysdeps/unix/sysv/linux/nios2/kernel_sigaction.h b/sysdeps/unix/sysv/linux/nios2/kernel_sigaction.h
new file mode 100644
index 0000000000..4ada322104
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/nios2/kernel_sigaction.h
@@ -0,0 +1,8 @@
+/* NIOS2 uses the generic Linux UAPI but defines SA_RESTORER.  */
+#define SA_RESTORER 0x04000000
+#include <sysdeps/unix/sysv/linux/kernel_sigaction.h>
+
+#define SET_SA_RESTORER(kact, act)             \
+  (kact)->sa_restorer = (act)->sa_restorer
+#define RESET_SA_RESTORER(act, kact)           \
+  (act)->sa_restorer = (kact)->sa_restorer
diff --git a/sysdeps/unix/sysv/linux/powerpc/kernel_sigaction.h b/sysdeps/unix/sysv/linux/powerpc/kernel_sigaction.h
new file mode 100644
index 0000000000..aef3d5a3b3
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/kernel_sigaction.h
@@ -0,0 +1,9 @@
+/* powerpc kernel sigaction is similar to generic Linux UAPI one,
+   but the architecture also defines SA_RESTORER.  */
+#define SA_RESTORER 0x04000000
+#include <sysdeps/unix/sysv/linux/kernel_sigaction.h>
+
+#define SET_SA_RESTORER(kact, act)             \
+  (kact)->sa_restorer = (act)->sa_restorer
+#define RESET_SA_RESTORER(act, kact)           \
+  (act)->sa_restorer = (kact)->sa_restorer
diff --git a/sysdeps/unix/sysv/linux/s390/kernel_sigaction.h b/sysdeps/unix/sysv/linux/s390/kernel_sigaction.h
new file mode 100644
index 0000000000..a8beaf7347
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/s390/kernel_sigaction.h
@@ -0,0 +1,28 @@
+#include <bits/types/siginfo_t.h>
+
+#define SA_RESTORER	0x04000000
+
+/* This is the sigaction structure from the Linux 3.2 kernel.  */
+struct kernel_sigaction
+{
+  union
+  {
+    __sighandler_t _sa_handler;
+    void (*_sa_sigaction)(int, siginfo_t *, void *);
+  } _u;
+#define k_sa_handler _u._sa_handler
+#ifndef __s390x__
+  sigset_t sa_mask;
+  unsigned long sa_flags;
+  void (*sa_restorer)(void);
+#else
+  unsigned long sa_flags;
+  void (*sa_restorer)(void);
+  sigset_t sa_mask;
+#endif
+};
+
+#define SET_SA_RESTORER(kact, act)             \
+  (kact)->sa_restorer = (act)->sa_restorer
+#define RESET_SA_RESTORER(act, kact)           \
+  (act)->sa_restorer = (kact)->sa_restorer
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/sigaction.c b/sysdeps/unix/sysv/linux/s390/s390-64/sigaction.c
deleted file mode 100644
index c13927ce9b..0000000000
--- a/sysdeps/unix/sysv/linux/s390/s390-64/sigaction.c
+++ /dev/null
@@ -1,43 +0,0 @@
-/* Copyright (C) 2001-2018 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/>.  */
-
-/* 64 bit Linux for S/390 only has rt signals, thus we do not even want to try
-   falling back to the old style signals as the default Linux handler does. */
-
-#include <errno.h>
-#include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* The variable is shared between all wrappers around signal handling
-   functions which have RT equivalents.  This is the definition.  */
-
-
-/* If ACT is not NULL, change the action for SIG to *ACT.
-   If OACT is not NULL, put the old action for SIG in *OACT.  */
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  return INLINE_SYSCALL (rt_sigaction, 4, sig, act, oact, _NSIG / 8);
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
diff --git a/sysdeps/unix/sysv/linux/sh/kernel_sigaction.h b/sysdeps/unix/sysv/linux/sh/kernel_sigaction.h
new file mode 100644
index 0000000000..7ebcd08d62
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sh/kernel_sigaction.h
@@ -0,0 +1,8 @@
+/* SH uses the generic Linux UAPI but defines SA_RESTORER.  */
+#define SA_RESTORER 0x04000000
+#include <sysdeps/unix/sysv/linux/kernel_sigaction.h>
+
+#define SET_SA_RESTORER(kact, act)             \
+  (kact)->sa_restorer = (act)->sa_restorer
+#define RESET_SA_RESTORER(act, kact)           \
+  (act)->sa_restorer = (kact)->sa_restorer
diff --git a/sysdeps/unix/sysv/linux/sigaction.c b/sysdeps/unix/sysv/linux/sigaction.c
index 40a311a3b3..0e6851a148 100644
--- a/sysdeps/unix/sysv/linux/sigaction.c
+++ b/sysdeps/unix/sysv/linux/sigaction.c
@@ -22,11 +22,19 @@
 #include <sysdep.h>
 #include <sys/syscall.h>
 
-/* The difference here is that the sigaction structure used in the
-   kernel is not the same as we use in the libc.  Therefore we must
-   translate it here.  */
+/* New ports should not define the obsolete SA_RESTORER, however some
+   architecture requires for compat mode and/or due old ABI.  */
 #include <kernel_sigaction.h>
 
+#ifndef SA_RESTORER
+# define SET_SA_RESTORER(kact, act)
+# define RESET_SA_RESTORER(act, kact)
+#endif
+
+/* SPARC passes the restore function as an argument to rt_sigaction.  */
+#ifndef STUB
+# define STUB(act)
+#endif
 
 /* If ACT is not NULL, change the action for SIG to *ACT.
    If OACT is not NULL, put the old action for SIG in *OACT.  */
@@ -42,25 +50,21 @@ __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
       kact.k_sa_handler = act->sa_handler;
       memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
       kact.sa_flags = act->sa_flags;
-#ifdef HAVE_SA_RESTORER
-      kact.sa_restorer = act->sa_restorer;
-#endif
+      SET_SA_RESTORER (&kact, act);
     }
 
   /* XXX The size argument hopefully will have to be changed to the
      real size of the user-level sigset_t.  */
-  result = INLINE_SYSCALL (rt_sigaction, 4, sig,
-			   act ? &kact : NULL,
-			   oact ? &koact : NULL, _NSIG / 8);
+  result = INLINE_SYSCALL_CALL (rt_sigaction, sig,
+				act ? &kact : NULL,
+				oact ? &koact : NULL, STUB(act) _NSIG / 8);
 
   if (oact && result >= 0)
     {
       oact->sa_handler = koact.k_sa_handler;
       memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
       oact->sa_flags = koact.sa_flags;
-#ifdef HAVE_SA_RESTORER
-      oact->sa_restorer = koact.sa_restorer;
-#endif
+      RESET_SA_RESTORER (oact, &koact);
     }
   return result;
 }
diff --git a/sysdeps/unix/sysv/linux/sparc/kernel_sigaction.h b/sysdeps/unix/sysv/linux/sparc/kernel_sigaction.h
new file mode 100644
index 0000000000..bee7e9cd03
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/kernel_sigaction.h
@@ -0,0 +1,10 @@
+/* SPARC 'struct __new_sigaction' is similar to generic Linux UAPI with
+   a sa_restorer field, even though function is passed as an argument
+   to rt_sigaction syscall.  */
+#define SA_RESTORER 0x04000000
+#include <sysdeps/unix/sysv/linux/kernel_sigaction.h>
+
+#define SET_SA_RESTORER(kact, act)             \
+  (kact)->sa_restorer = NULL
+#define RESET_SA_RESTORER(act, kact)           \
+  (act)->sa_restorer = (kact)->sa_restorer
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c b/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
index 204a5d88c6..191f58729e 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
@@ -27,43 +27,13 @@
 static void __rt_sigreturn_stub (void);
 static void __sigreturn_stub (void);
 
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  struct kernel_sigaction kact, koact;
-  unsigned long stub = 0;
-  int ret;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
-      if (((kact.sa_flags = act->sa_flags) & SA_SIGINFO) != 0)
-	stub = (unsigned long) &__rt_sigreturn_stub;
-      else
-	stub = (unsigned long) &__sigreturn_stub;
-      stub -= 8;
-      kact.sa_restorer = NULL;
-    }
-
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  ret = INLINE_SYSCALL (rt_sigaction, 5, sig, act ? &kact : 0,
-			oact ? &koact : 0, stub, _NSIG / 8);
-
-  if (oact && ret >= 0)
-    {
-      oact->sa_handler = koact.k_sa_handler;
-      memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
-      oact->sa_flags = koact.sa_flags;
-      oact->sa_restorer = koact.sa_restorer;
-    }
-  return ret;
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
+#define STUB(act) \
+  (act) ? ((unsigned long)((act->sa_flags & SA_SIGINFO)	\
+			    ? &__rt_sigreturn_stub	\
+			    : &__sigreturn_stub) - 8)	\
+	: 0,
 
+#include <sysdeps/unix/sysv/linux/sigaction.c>
 
 static
 inhibit_stack_protector
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c b/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
index 73cda4c6e4..cfbbc6e7b4 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
@@ -21,50 +21,13 @@
 #include <string.h>
 #include <syscall.h>
 #include <sysdep.h>
-#include <sys/signal.h>
-#include <errno.h>
-
-#include <kernel_sigaction.h>
-
-/* SPARC 64bit userland requires a kernel that has rt signals anyway. */
 
 static void __rt_sigreturn_stub (void);
 
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  int ret;
-  struct kernel_sigaction kact, koact;
-  unsigned long stub = ((unsigned long) &__rt_sigreturn_stub) - 8;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
-      kact.sa_flags = act->sa_flags;
-      kact.sa_restorer = NULL;
-    }
-
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  ret = INLINE_SYSCALL (rt_sigaction, 5, sig,
-			act ? &kact : 0,
-			oact ? &koact : 0, stub, _NSIG / 8);
-
-  if (oact && ret >= 0)
-    {
-      oact->sa_handler = koact.k_sa_handler;
-      memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
-      oact->sa_flags = koact.sa_flags;
-      oact->sa_restorer = koact.sa_restorer;
-    }
-
-  return ret;
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
+#define STUB(act) \
+  (((unsigned long) &__rt_sigreturn_stub) - 8),
 
+#include <sysdeps/unix/sysv/linux/sigaction.c>
 
 static
 inhibit_stack_protector
diff --git a/sysdeps/unix/sysv/linux/tile/kernel_sigaction.h b/sysdeps/unix/sysv/linux/tile/kernel_sigaction.h
new file mode 100644
index 0000000000..a943d520ce
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tile/kernel_sigaction.h
@@ -0,0 +1,9 @@
+/* tile kernel sigaction is similar to generic Linux UAPI one
+   and SA_RESTORER is used only for binary compatibility.  */
+#define SA_RESTORER 0x04000000
+#include <sysdeps/unix/sysv/linux/kernel_sigaction.h>
+
+#define SET_SA_RESTORER(kact, act)             \
+  (kact)->sa_restorer = (act)->sa_restorer
+#define RESET_SA_RESTORER(act, kact)           \
+  (act)->sa_restorer = (kact)->sa_restorer
diff --git a/sysdeps/unix/sysv/linux/x86_64/sigaction.c b/sysdeps/unix/sysv/linux/x86_64/sigaction.c
index 2f7459f6fc..4e6d9cc32e 100644
--- a/sysdeps/unix/sysv/linux/x86_64/sigaction.c
+++ b/sysdeps/unix/sysv/linux/x86_64/sigaction.c
@@ -16,65 +16,20 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <sysdep.h>
-#include <errno.h>
-#include <stddef.h>
 #include <signal.h>
-#include <string.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* The difference here is that the sigaction structure used in the
-   kernel is not the same as we use in the libc.  Therefore we must
-   translate it here.  */
-#include <kernel_sigaction.h>
-
-#include "ucontext_i.h"
-
-/* We do not globally define the SA_RESTORER flag so do it here.  */
 #define SA_RESTORER 0x04000000
+#include <kernel_sigaction.h>
 
-/* Using the hidden attribute here does not change the code but it
-   helps to avoid warnings.  */
 extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;
 
+#define SET_SA_RESTORER(kact, act)			\
+  (kact)->sa_flags = (act)->sa_flags | SA_RESTORER;	\
+  (kact)->sa_restorer = &restore_rt
 
-/* If ACT is not NULL, change the action for SIG to *ACT.
-   If OACT is not NULL, put the old action for SIG in *OACT.  */
-int
-__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
-{
-  int result;
-  struct kernel_sigaction kact, koact;
-
-  if (act)
-    {
-      kact.k_sa_handler = act->sa_handler;
-      memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
-      kact.sa_flags = act->sa_flags | SA_RESTORER;
-
-      kact.sa_restorer = &restore_rt;
-    }
-
-  /* XXX The size argument hopefully will have to be changed to the
-     real size of the user-level sigset_t.  */
-  result = INLINE_SYSCALL (rt_sigaction, 4,
-			   sig, act ? &kact : NULL,
-			   oact ? &koact : NULL, _NSIG / 8);
-  if (oact && result >= 0)
-    {
-      oact->sa_handler = koact.k_sa_handler;
-      memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
-      oact->sa_flags = koact.sa_flags;
-      oact->sa_restorer = koact.sa_restorer;
-    }
-  return result;
-}
-libc_hidden_def (__libc_sigaction)
-
-#include <nptl/sigaction.c>
+#define RESET_SA_RESTORER(act, kact) 			\
+  (act)->sa_restorer = (kact)->sa_restorer
 
+#include <sysdeps/unix/sysv/linux/sigaction.c>
 
 /* NOTE: Please think twice before making any changes to the bits of
    code below.  GDB needs some intimate knowledge about it to
@@ -93,6 +48,8 @@ libc_hidden_def (__libc_sigaction)
    a bit tricky.  We don't use the gas cfi directives, so that we can
    reliably add .cfi_signal_frame.  */
 
+#include "ucontext_i.h"
+
 #define do_cfa_expr						\
   "	.byte 0x0f\n"		/* DW_CFA_def_cfa_expression */	\
   "	.uleb128 2f-1f\n"	/* length */			\