[2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543)

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* [2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543)
@ 2020-03-10 13:34 Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] linux: Clear mode_t padding bits (BZ#25623) Adhemerval Zanella
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-03-10 13:34 UTC (permalink / raw)
  To: libc-stable

GCC has moved from using .gnu.linkonce for i386 setup pic register with
minimum current version (as for binutils minimum binutils that support
comdat).

Trying to pinpoint when binutils has added comdat support for i686, it
seems it was around 2004 [1].  I also checking with some ancient
binutils older than 2.16 I see:

test.o: In function `__x86.get_pc_thunk.bx':
test.o(.text.__x86.get_pc_thunk.bx+0x0): multiple definition of `__x86.get_pc_thunk.bx'
/usr/lib/gcc/x86_64-linux-gnu/5/../../../i386-linux-gnu/crti.o(.gnu.linkonce.t.__x86.get_pc_thunk.bx+0x0): first defined here

Which seems that such version can not handle either comdat at all or
a mix of linkonce and comdat.  For binutils 2.16.1 I am getting a
different issue trying to link a binary with and more recent
ctri.o (unrecognized relocation (0x2b) in section `.init', which is
R_386_GOT32X and old binutils won't generate it anyway).

So I think that either unlikely someone will use an older binutils than
the one used to glibc and even this scenario may fail with some issue
as the R_386_GOT32X.  Also, 2.16.1 is quite old and not really supported
(glibc itself required 2.25).

Checked on i686-linux-gnu.

[1] https://gcc.gnu.org/ml/gcc/2004-05/msg00030.html

(cherry picked from commit 35200fd3892f6caf867bf89bc8048e553906af28)
---
 sysdeps/i386/sysdep.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sysdeps/i386/sysdep.h b/sysdeps/i386/sysdep.h
index b4bcd8fb6c..6094af8fec 100644
--- a/sysdeps/i386/sysdep.h
+++ b/sysdeps/i386/sysdep.h
@@ -61,7 +61,7 @@ lose: SYSCALL_PIC_SETUP							      \

 # define SETUP_PIC_REG(reg) \
   .ifndef GET_PC_THUNK(reg);						      \
-  .section .gnu.linkonce.t.GET_PC_THUNK(reg),"ax",@progbits;		      \
+  .section .text.GET_PC_THUNK(reg),"axG",@progbits,GET_PC_THUNK(reg),comdat;  \
   .globl GET_PC_THUNK(reg);						      \
   .hidden GET_PC_THUNK(reg);						      \
   .p2align 4;								      \
@@ -97,7 +97,8 @@ GET_PC_THUNK(reg):							      \

 # define SETUP_PIC_REG_STR(reg)						\
   ".ifndef " GET_PC_THUNK_STR (reg) "\n"				\
-  ".section .gnu.linkonce.t." GET_PC_THUNK_STR (reg) ",\"ax\",@progbits\n" \
+  ".section .text." GET_PC_THUNK_STR (reg) ",\"axG\",@progbits,"	\
+    GET_PC_THUNK_STR (reg) ",comdat\n"					\
   ".globl " GET_PC_THUNK_STR (reg) "\n"					\
   ".hidden " GET_PC_THUNK_STR (reg) "\n"				\
   ".p2align 4\n"							\
-- 
2.17.1

^ permalink raw reply	[flat|nested] 5+ messages in thread

* [2.31 COMMITTED] linux: Clear mode_t padding bits (BZ#25623)
  2020-03-10 13:34 [2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543) Adhemerval Zanella
@ 2020-03-10 13:34 ` Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] linux/sysipc: Include linux/posix_types.h for __kernel_mode_t Adhemerval Zanella
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-03-10 13:34 UTC (permalink / raw)
  To: libc-stable

The kernel might not clear the padding value for the ipc_perm mode
fields in compat mode (32 bit running on a 64 bit kernel).  It was
fixed on v4.14 when the ipc compat code was refactored to move
(commits 553f770ef71b, 469391684626, c0ebccb6fa1e).

Although it is most likely a kernel issue, it was shown only due
BZ#18231 fix which made all the SysVIPC mode_t 32-bit regardless of
the kABI.

This patch fixes it by explicitly zeroing the upper bits for such
cases.  The __ASSUME_SYSVIPC_BROKEN_MODE_T case already handles
it with the shift.

(The aarch64 ipc_priv.h is superflous since
__ASSUME_SYSVIPC_DEFAULT_IPC_64 is now defined as default).

Checked on i686-linux-gnu on 3.10 and on 4.15 kernel.

(cherry picked from commit 82025bad80429c67a4d75f098155b5e02b5112b4)
---
 sysdeps/unix/sysv/linux/msgctl.c | 9 +++++++--
 sysdeps/unix/sysv/linux/semctl.c | 9 +++++++--
 sysdeps/unix/sysv/linux/shmctl.c | 9 +++++++--
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/msgctl.c b/sysdeps/unix/sysv/linux/msgctl.c
index 27879e76cd..eb28835b3a 100644
--- a/sysdeps/unix/sysv/linux/msgctl.c
+++ b/sysdeps/unix/sysv/linux/msgctl.c
@@ -61,7 +61,6 @@ __new_msgctl (int msqid, int cmd, struct msqid_ds *buf)
 
   int ret = msgctl_syscall (msqid, cmd, buf);
 
-#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
   if (ret >= 0)
     {
       switch (cmd)
@@ -69,10 +68,16 @@ __new_msgctl (int msqid, int cmd, struct msqid_ds *buf)
 	case IPC_STAT:
 	case MSG_STAT:
 	case MSG_STAT_ANY:
+#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
 	  buf->msg_perm.mode >>= 16;
+#else
+	  /* Old Linux kernel versions might not clear the mode padding.  */
+	  if (sizeof ((struct msqid_ds){0}.msg_perm.mode)
+	      != sizeof (__kernel_mode_t))
+	    buf->msg_perm.mode &= 0xFFFF;
+#endif
 	}
     }
-#endif
 
   return ret;
 }
diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
index 0c3eb0932f..0a79e8e4f5 100644
--- a/sysdeps/unix/sysv/linux/semctl.c
+++ b/sysdeps/unix/sysv/linux/semctl.c
@@ -92,7 +92,6 @@ __new_semctl (int semid, int semnum, int cmd, ...)
 
   int ret = semctl_syscall (semid, semnum, cmd, arg);
 
-#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
   if (ret >= 0)
     {
       switch (cmd)
@@ -100,10 +99,16 @@ __new_semctl (int semid, int semnum, int cmd, ...)
         case IPC_STAT:
         case SEM_STAT:
         case SEM_STAT_ANY:
+#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
           arg.buf->sem_perm.mode >>= 16;
+#else
+	  /* Old Linux kernel versions might not clear the mode padding.  */
+	  if (sizeof ((struct semid_ds){0}.sem_perm.mode)
+	      != sizeof (__kernel_mode_t))
+	    arg.buf->sem_perm.mode &= 0xFFFF;
+#endif
 	}
     }
-#endif
 
   return ret;
 }
diff --git a/sysdeps/unix/sysv/linux/shmctl.c b/sysdeps/unix/sysv/linux/shmctl.c
index 39fa861e17..aed9e5260e 100644
--- a/sysdeps/unix/sysv/linux/shmctl.c
+++ b/sysdeps/unix/sysv/linux/shmctl.c
@@ -63,7 +63,6 @@ __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
 
   int ret = shmctl_syscall (shmid, cmd, buf);
 
-#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
   if (ret >= 0)
     {
       switch (cmd)
@@ -71,10 +70,16 @@ __new_shmctl (int shmid, int cmd, struct shmid_ds *buf)
         case IPC_STAT:
         case SHM_STAT:
         case SHM_STAT_ANY:
+#ifdef __ASSUME_SYSVIPC_BROKEN_MODE_T
           buf->shm_perm.mode >>= 16;
+#else
+	  /* Old Linux kernel versions might not clear the mode padding.  */
+	  if (sizeof ((struct shmid_ds){0}.shm_perm.mode)
+	      != sizeof (__kernel_mode_t))
+	    buf->shm_perm.mode &= 0xFFFF;
+#endif
 	}
     }
-#endif
 
   return ret;
 }
-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [2.31 COMMITTED] linux/sysipc: Include linux/posix_types.h for __kernel_mode_t
  2020-03-10 13:34 [2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543) Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] linux: Clear mode_t padding bits (BZ#25623) Adhemerval Zanella
@ 2020-03-10 13:34 ` Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] arm: Fix softp-fp Implies (BZ #25635) Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] sparc: Move sigreturn stub to assembly Adhemerval Zanella
  3 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-03-10 13:34 UTC (permalink / raw)
  To: libc-stable

The posix_types.h (where __kernel_mode_t is defined) is included
implicitly, which might not happen on older kernels.

(cherry picked from commit 7aec9f4e5e0313772d123ba4daa96ea921a50aec)
---
 sysdeps/unix/sysv/linux/msgctl.c | 1 +
 sysdeps/unix/sysv/linux/semctl.c | 1 +
 sysdeps/unix/sysv/linux/shmctl.c | 1 +
 3 files changed, 3 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/msgctl.c b/sysdeps/unix/sysv/linux/msgctl.c
index eb28835b3a..fd46aec1a0 100644
--- a/sysdeps/unix/sysv/linux/msgctl.c
+++ b/sysdeps/unix/sysv/linux/msgctl.c
@@ -21,6 +21,7 @@
 #include <sysdep.h>
 #include <shlib-compat.h>
 #include <errno.h>
+#include <linux/posix_types.h>  /* For __kernel_mode_t.  */
 
 #ifndef DEFAULT_VERSION
 # ifndef __ASSUME_SYSVIPC_BROKEN_MODE_T
diff --git a/sysdeps/unix/sysv/linux/semctl.c b/sysdeps/unix/sysv/linux/semctl.c
index 0a79e8e4f5..30571af49f 100644
--- a/sysdeps/unix/sysv/linux/semctl.c
+++ b/sysdeps/unix/sysv/linux/semctl.c
@@ -22,6 +22,7 @@
 #include <sysdep.h>
 #include <shlib-compat.h>
 #include <errno.h>
+#include <linux/posix_types.h>  /* For __kernel_mode_t.  */
 
 /* Define a `union semun' suitable for Linux here.  */
 union semun
diff --git a/sysdeps/unix/sysv/linux/shmctl.c b/sysdeps/unix/sysv/linux/shmctl.c
index aed9e5260e..f41b359b8b 100644
--- a/sysdeps/unix/sysv/linux/shmctl.c
+++ b/sysdeps/unix/sysv/linux/shmctl.c
@@ -22,6 +22,7 @@
 #include <sysdep.h>
 #include <shlib-compat.h>
 #include <errno.h>
+#include <linux/posix_types.h>  /* For __kernel_mode_t.  */
 
 #ifndef DEFAULT_VERSION
 # ifndef __ASSUME_SYSVIPC_BROKEN_MODE_T
-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [2.31 COMMITTED] arm: Fix softp-fp Implies (BZ #25635)
  2020-03-10 13:34 [2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543) Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] linux: Clear mode_t padding bits (BZ#25623) Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] linux/sysipc: Include linux/posix_types.h for __kernel_mode_t Adhemerval Zanella
@ 2020-03-10 13:34 ` Adhemerval Zanella
  2020-03-10 13:34 ` [2.31 COMMITTED] sparc: Move sigreturn stub to assembly Adhemerval Zanella
  3 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-03-10 13:34 UTC (permalink / raw)
  To: libc-stable

The commit "arm: Split BE/LE abilist"
(1673ba87fefe019c834c09d33673d1d453ea698d) changed the soft-fp order for
ARM selection when __SOFTFP__ is defined by the compiler.

On 2.30 the sysdeps order is:

2.30
sysdeps/unix/sysv/linux/arm
sysdeps/arm/nptl
sysdeps/unix/sysv/linux
sysdeps/nptl
sysdeps/pthread
sysdeps/gnu
sysdeps/unix/inet
sysdeps/unix/sysv
sysdeps/unix/arm
sysdeps/unix
sysdeps/posix
sysdeps/arm/nofpu
sysdeps/ieee754/soft-fp
sysdeps/arm
sysdeps/wordsize-32
sysdeps/ieee754/flt-32
sysdeps/ieee754/dbl-64
sysdeps/ieee754
sysdeps/generic

While on master is:

sysdeps/unix/sysv/linux/arm/le
sysdeps/unix/sysv/linux/arm
sysdeps/arm/nptl
sysdeps/unix/sysv/linux
sysdeps/nptl
sysdeps/pthread
sysdeps/gnu
sysdeps/unix/inet
sysdeps/unix/sysv
sysdeps/unix/arm
sysdeps/unix
sysdeps/posix
sysdeps/arm/le
sysdeps/arm
sysdeps/wordsize-32
sysdeps/ieee754/flt-32
sysdeps/ieee754/dbl-64
sysdeps/arm/nofpu
sysdeps/ieee754/soft-fp
sysdeps/ieee754
sysdeps/generic

It make the build select some routines (fadd, fdiv, fmul, fsub, and fma)
on ieee754/flt-32 and ieee754/dbl-64 that requires fenv support to be
correctly rounded which in turns lead to math failures since the
__SOFTFP__ does not have fenv support.

With this patch the order is now:

sysdeps/unix/sysv/linux/arm/le
sysdeps/unix/sysv/linux/arm
sysdeps/arm/nptl
sysdeps/unix/sysv/linux
sysdeps/nptlsysdeps/pthread
sysdeps/gnu
sysdeps/unix/inet
sysdeps/unix/sysv
sysdeps/unix/arm
sysdeps/unix
sysdeps/posix
sysdeps/arm/le/nofpu
sysdeps/arm/nofpu
sysdeps/ieee754/soft-fp
sysdeps/arm/le
sysdeps/arm
sysdeps/wordsize-32
sysdeps/ieee754/flt-32
sysdeps/ieee754/dbl-64
sysdeps/ieee754
sysdeps/generic

Checked on arm-linux-gnuaebi.

(cherry picked from commit af09e5e5d9ec3ca20891e61a6922eac984fcbdc4)
---
 sysdeps/arm/be/nofpu/Implies | 1 +
 sysdeps/arm/le/nofpu/Implies | 1 +
 2 files changed, 2 insertions(+)
 create mode 100644 sysdeps/arm/be/nofpu/Implies
 create mode 100644 sysdeps/arm/le/nofpu/Implies

diff --git a/sysdeps/arm/be/nofpu/Implies b/sysdeps/arm/be/nofpu/Implies
new file mode 100644
index 0000000000..c90dd7fd5c
--- /dev/null
+++ b/sysdeps/arm/be/nofpu/Implies
@@ -0,0 +1 @@
+arm/nofpu
diff --git a/sysdeps/arm/le/nofpu/Implies b/sysdeps/arm/le/nofpu/Implies
new file mode 100644
index 0000000000..c90dd7fd5c
--- /dev/null
+++ b/sysdeps/arm/le/nofpu/Implies
@@ -0,0 +1 @@
+arm/nofpu
-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [2.31 COMMITTED] sparc: Move sigreturn stub to assembly
  2020-03-10 13:34 [2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543) Adhemerval Zanella
                   ` (2 preceding siblings ...)
  2020-03-10 13:34 ` [2.31 COMMITTED] arm: Fix softp-fp Implies (BZ #25635) Adhemerval Zanella
@ 2020-03-10 13:34 ` Adhemerval Zanella
  3 siblings, 0 replies; 5+ messages in thread
From: Adhemerval Zanella @ 2020-03-10 13:34 UTC (permalink / raw)
  To: libc-stable

It seems that some gcc versions might generates a stack frame for the
sigreturn stub requires on sparc signal handling.  For instance:

  $ cat test.c
  #define _GNU_SOURCE
  #include <sys/syscall.h>

  __attribute__ ((__optimize__ ("-fno-stack-protector")))
  void
  __sigreturn_stub (void)
  {
    __asm__ ("mov %0, %%g1\n\t"
            "ta  0x10\n\t"
            : /* no outputs */
            : "i" (SYS_rt_sigreturn));
  }
  $ gcc -v
  [...]
  gcc version 9.2.1 20200224 (Debian 9.2.1-30)
  $ gcc -O2 -m64 test.c -S -o -
  [...]
    __sigreturn_stub:
          save    %sp, -176, %sp
  #APP
  ! 9 "t.c" 1
          mov 101, %g1
          ta  0x10

  ! 0 "" 2
  #NO_APP
          .size   __sigreturn_stub, .-__sigreturn_stub

As indicated by kernel developers [1], the sigreturn stub can not change
the register window or the stack pointer since the kernel has setup the
restore frame at a precise location relative to the stack pointer when
the stub is invoked.

I tried to play with some compiler flags and even with _Noreturn and
__builtin_unreachable after the asm does not help (and Sparc does not
support naked functions).

To avoid similar issues, as the stack-protector support also have
stumbled, this patch moves the implementation of the sigreturn stubs to
assembly.

Checked on sparcv9-linux-gnu and sparc64-linux-gnu with gcc 9.2.1
and gcc 7.5.0.

[1] https://lkml.org/lkml/2016/5/27/465
---
 sysdeps/unix/sysv/linux/sparc/Makefile        |  8 +++--
 .../unix/sysv/linux/sparc/sparc32/sigaction.c | 26 ++------------
 .../sysv/linux/sparc/sparc32/sigreturn_stub.S | 34 +++++++++++++++++++
 .../unix/sysv/linux/sparc/sparc64/sigaction.c | 14 ++------
 .../sysv/linux/sparc/sparc64/sigreturn_stub.S | 29 ++++++++++++++++
 5 files changed, 73 insertions(+), 38 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S
 create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/sigreturn_stub.S

diff --git a/sysdeps/unix/sysv/linux/sparc/Makefile b/sysdeps/unix/sysv/linux/sparc/Makefile
index b0d182a439..1475039677 100644
--- a/sysdeps/unix/sysv/linux/sparc/Makefile
+++ b/sysdeps/unix/sysv/linux/sparc/Makefile
@@ -11,8 +11,12 @@ ifeq ($(subdir),sysvipc)
 sysdep_routines += getshmlba
 endif
 
+ifeq ($(subdir),signal)
+sysdep_routines += sigreturn_stub
+endif
+
 ifeq ($(subdir),nptl)
 # pull in __syscall_error routine
-libpthread-routines += sysdep
-libpthread-shared-only-routines += sysdep
+libpthread-routines += sysdep sigreturn_stub
+libpthread-shared-only-routines += sysdep sigreturn_stub
 endif
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c b/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
index 6b2f664226..938aa7aa8c 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
@@ -24,8 +24,8 @@
 #include <kernel_sigaction.h>
 #include <sysdep.h>
 
-static void __rt_sigreturn_stub (void);
-static void __sigreturn_stub (void);
+void __rt_sigreturn_stub (void);
+void __sigreturn_stub (void);
 
 #define STUB(act, sigsetsize) \
   (act) ? ((unsigned long)((act->sa_flags & SA_SIGINFO)	\
@@ -35,25 +35,3 @@ static void __sigreturn_stub (void);
   (sigsetsize)
 
 #include <sysdeps/unix/sysv/linux/sigaction.c>
-
-static
-inhibit_stack_protector
-void
-__rt_sigreturn_stub (void)
-{
-  __asm__ ("mov %0, %%g1\n\t"
-	   "ta	0x10\n\t"
-	   : /* no outputs */
-	   : "i" (__NR_rt_sigreturn));
-}
-
-static
-inhibit_stack_protector
-void
-__sigreturn_stub (void)
-{
-  __asm__ ("mov %0, %%g1\n\t"
-	   "ta	0x10\n\t"
-	   : /* no outputs */
-	   : "i" (__NR_sigreturn));
-}
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S b/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S
new file mode 100644
index 0000000000..727cc94737
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/sigreturn_stub.S
@@ -0,0 +1,34 @@
+/* Sigreturn stub function used on sa_restore field.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+/* These functions must not change the register window or the stack
+   pointer [1].
+
+   [1] https://lkml.org/lkml/2016/5/27/465  */
+
+ENTRY (__rt_sigreturn_stub)
+	mov	__NR_rt_sigreturn, %g1
+	ta	0x10
+END (__rt_sigreturn_stub)
+
+ENTRY (__sigreturn_stub)
+	mov	__NR_sigreturn, %g1
+	ta	0x10
+END (__sigreturn_stub)
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c b/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
index 9c0dc2a630..4e26172321 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/sigaction.c
@@ -22,21 +22,11 @@
 #include <syscall.h>
 #include <sysdep.h>
 
-static void __rt_sigreturn_stub (void);
+/* Defined on sigreturn_stub.S.  */
+void __rt_sigreturn_stub (void);
 
 #define STUB(act, sigsetsize) \
   (((unsigned long) &__rt_sigreturn_stub) - 8),	\
   (sigsetsize)
 
 #include <sysdeps/unix/sysv/linux/sigaction.c>
-
-static
-inhibit_stack_protector
-void
-__rt_sigreturn_stub (void)
-{
-  __asm__ ("mov %0, %%g1\n\t"
-	   "ta	0x6d\n\t"
-	   : /* no outputs */
-	   : "i" (__NR_rt_sigreturn));
-}
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/sigreturn_stub.S b/sysdeps/unix/sysv/linux/sparc/sparc64/sigreturn_stub.S
new file mode 100644
index 0000000000..add4766831
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/sigreturn_stub.S
@@ -0,0 +1,29 @@
+/* Sigreturn stub function used on sa_restore field.
+   Copyright (C) 2020 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+
+/* This function must not change the register window or the stack
+   pointer [1].
+
+   [1] https://lkml.org/lkml/2016/5/27/465  */
+
+ENTRY (__rt_sigreturn_stub)
+	mov	__NR_rt_sigreturn, %g1
+	ta	0x6d
+END (__rt_sigreturn_stub)
-- 
2.17.1


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2020-03-10 13:35 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-10 13:34 [2.31 COMMITTED] i386: Use comdat instead of .gnu.linkonce for i386 setup pic register (BZ #20543) Adhemerval Zanella
2020-03-10 13:34 ` [2.31 COMMITTED] linux: Clear mode_t padding bits (BZ#25623) Adhemerval Zanella
2020-03-10 13:34 ` [2.31 COMMITTED] linux/sysipc: Include linux/posix_types.h for __kernel_mode_t Adhemerval Zanella
2020-03-10 13:34 ` [2.31 COMMITTED] arm: Fix softp-fp Implies (BZ #25635) Adhemerval Zanella
2020-03-10 13:34 ` [2.31 COMMITTED] sparc: Move sigreturn stub to assembly Adhemerval Zanella

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