[PATCH v2 17/23] linux: Use generic __syscall_error for m68k

Adhemerval Zanella adhemerval.zanella@linaro.org
Fri Nov 13 16:58:31 GMT 2020


Although the auto-generated syscall sets errno directly for dynamic
case, using a function call generates more compact code:

--- sizes-m68k-linux-gnu.inline
+++ sizes-m68k-linux-gnu.outline
    text           data     bss     dec     hex filename
-1283686          20376    9304 1313366  140a56 libc.so
- 119206           5960     184  125350   1e9a6 elf/ld.so
-  87078           1456    8360   96894   17a7e nptl/libpthread.so
-  23918            888     160   24966    6186 rt/librt.so
+1277602          20376    9304 1307282  13f292 libc.so
+ 119174           5960     184  125318   1e986 elf/ld.so
+  86314           1456    8360   96130   17782 nptl/libpthread.so
+  23562            888     160   24610    6022 rt/librt.so

Checked with some basic tests to see if errno is set correctly
on both static and dynamic binaries with auto-generated syscals
and C implementation (which uses INTERNAL_SYSCALL_CALL).
---
 sysdeps/unix/sysv/linux/m68k/syscall_error.h | 25 ++++++++++
 sysdeps/unix/sysv/linux/m68k/sysdep.S        | 50 --------------------
 sysdeps/unix/sysv/linux/m68k/sysdep.h        |  9 ++--
 3 files changed, 29 insertions(+), 55 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/m68k/syscall_error.h
 delete mode 100644 sysdeps/unix/sysv/linux/m68k/sysdep.S

diff --git a/sysdeps/unix/sysv/linux/m68k/syscall_error.h b/sysdeps/unix/sysv/linux/m68k/syscall_error.h
new file mode 100644
index 0000000000..4ea7cbdad5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/m68k/syscall_error.h
@@ -0,0 +1,25 @@
+/* Linux wrappers for setting errno.  m68k version.
+   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/>.  */
+
+#ifndef _SYSCALL_ERROR_H
+#define _SYSCALL_ERROR_H
+
+#define SYSCALL_ERROR_FUNC        1
+#define SYSCALL_ERROR_FUNC_ATTR
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/m68k/sysdep.S b/sysdeps/unix/sysv/linux/m68k/sysdep.S
deleted file mode 100644
index 1313ab17c3..0000000000
--- a/sysdeps/unix/sysv/linux/m68k/sysdep.S
+++ /dev/null
@@ -1,50 +0,0 @@
-/* Copyright (C) 1996-2020 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>
-
-
-/* The following code is only used in the shared library when we
-   compile the reentrant version.  Otherwise each system call defines
-   each own version.  */
-
-#ifndef	PIC
-
-/* The syscall stubs jump here when they detect an error.  */
-
-#undef CALL_MCOUNT
-#define CALL_MCOUNT /* Don't insert the profiling call, it clobbers %d0.  */
-
-	.text
-ENTRY (__syscall_error)
-	neg.l %d0
-#ifndef _LIBC_REENTRANT
-	move.l %d0, errno
-#else
-	move.l %d0, -(%sp)
-	cfi_adjust_cfa_offset (4)
-	jbsr __errno_location
-	move.l (%sp)+, (%a0)
-	cfi_adjust_cfa_offset (-4)
-#endif
-	move.l #-1, %d0
-	/* Copy return value to %a0 for syscalls that are declared to
-	   return a pointer.  */
-	move.l %d0, %a0
-	rts
-END (__syscall_error)
-#endif /* PIC */
diff --git a/sysdeps/unix/sysv/linux/m68k/sysdep.h b/sysdeps/unix/sysv/linux/m68k/sysdep.h
index 3e0ab605de..24835be910 100644
--- a/sysdeps/unix/sysv/linux/m68k/sysdep.h
+++ b/sysdeps/unix/sysv/linux/m68k/sysdep.h
@@ -45,11 +45,7 @@
 /* We don't want the label for the error handler to be visible in the symbol
    table when we define it here.  */
 #undef SYSCALL_ERROR_LABEL
-#ifdef PIC
 #define SYSCALL_ERROR_LABEL .Lsyscall_error
-#else
-#define SYSCALL_ERROR_LABEL __syscall_error
-#endif
 
 #undef PSEUDO
 #define	PSEUDO(name, syscall_name, args)				      \
@@ -137,7 +133,10 @@ SYSCALL_ERROR_LABEL:							      \
     rts;
 # endif /* _LIBC_REENTRANT */
 #else
-# define SYSCALL_ERROR_HANDLER	/* Nothing here; code in sysdep.S is used.  */
+# define SYSCALL_ERROR_HANDLER						      \
+SYSCALL_ERROR_LABEL:							      \
+    move.l %d0,4(%sp);							      \
+    bra.l __syscall_error
 #endif /* PIC */
 
 /* Linux takes system call arguments in registers:
-- 
2.25.1



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