On Mon, Oct 12, 2015 at 4:20 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> This patch removes i386 assembly implementation for epoll_wait, mmap,
> mmap64, semtimeop now that i386 have 6 argument syscall support from
> C code and GCC 5 can inline syscalls with 6 argument. We also compile
> epoll_pwait.c, mmap.c, mmap64.c and semtimedop.c with -fomit-frame-pointer
> since %ebp may be used to pass the 6th argument to syscall.
>
> Fo sysdeps/unix/sysv/linux/i386/mmap.c, with -O2 -march=i686
> -mtune=generic, GCC 5.2 now generates:
>
> <__mmap>:
> 0: sub $0x10,%esp
> 3: mov 0x28(%esp),%eax
> 7: mov %ebx,(%esp)
> a: mov 0x18(%esp),%ecx
> e: mov %esi,0x4(%esp)
> 12: mov 0x14(%esp),%ebx
> 16: mov %edi,0x8(%esp)
> 1a: mov 0x1c(%esp),%edx
> 1e: test $0xfff,%eax
> 23: mov 0x20(%esp),%esi
> 27: mov %ebp,0xc(%esp)
> 2b: mov 0x24(%esp),%edi
> 2f: jne 60 <__mmap+0x60>
> 31: shr $0xc,%eax
> 34: mov %eax,%ebp
> 36: mov $0xc0,%eax
> 3b: call *%gs:0x10
> 42: cmp $0xfffff000,%eax
> 47: ja 65 <__mmap+0x65>
> 49: mov (%esp),%ebx
> 4c: mov 0x4(%esp),%esi
> 50: mov 0x8(%esp),%edi
> 54: mov 0xc(%esp),%ebp
> 58: add $0x10,%esp
> 5b: ret
> 5c: lea 0x0(%esi,%eiz,1),%esi
> 60: mov $0xffffffea,%eax
> 65: mov (%esp),%ebx
> 68: mov 0x4(%esp),%esi
> 6c: mov 0x8(%esp),%edi
> 70: mov 0xc(%esp),%ebp
> 74: add $0x10,%esp
> 77: jmp 78 <__mmap+0x78>
>
> vs sysdeps/unix/sysv/linux/i386/mmap.S:
>
> <__mmap>:
> 0: push %ebp
> 1: push %ebx
> 2: push %esi
> 3: push %edi
> 4: mov 0x14(%esp),%ebx
> 8: mov 0x18(%esp),%ecx
> c: mov 0x1c(%esp),%edx
> 10: mov 0x20(%esp),%esi
> 14: mov 0x24(%esp),%edi
> 18: mov 0x28(%esp),%ebp
> 1c: test $0xfff,%ebp
> 22: mov $0xffffffea,%eax
> 27: jne 38 <__mmap+0x38>
> 29: shr $0xc,%ebp
> 2c: mov $0xc0,%eax
> 31: call *%gs:0x10
> 38: pop %edi
> 39: pop %esi
> 3a: pop %ebx
> 3b: pop %ebp
> 3c: cmp $0xfffff000,%eax
> 41: ja 44 <__mmap+0x44>
> 43: ret
> 44: call 45 <__mmap+0x45> 45: R_386_PC32 __x86.get_pc_thunk.cx
> 49: add $0x2,%ecx 4b: R_386_GOTPC _GLOBAL_OFFSET_TABLE_
> 4f: mov 0x0(%ecx),%ecx 51: R_386_TLS_GOTIE __libc_errno
> 55: neg %eax
> 57: mov %eax,%gs:(%ecx)
> 5a: or $0xffffffff,%eax
> 5d: ret
>
> The C version has:
>
> 3: mov 0x28(%esp),%eax
> ...
> 1e: test $0xfff,%eax
> ...
> 31: sar $0xc,%eax
> 34: mov %eax,%ebp
>
> is due to missing $ebx register constraint for inline asm. We have
> to use "r" constraint with
>
> register unsigned int _a6 asm ("ebp") = (unsigned int) (arg6);
>
> and compiler chose %eax for offset (arg6) in
>
> if (offset & (MMAP_PAGE_UNIT - 1))
>
> * sysdeps/unix/sysv/linux/i386/Makefile (CFLAGS-epoll_pwait.c):
> Add -fomit-frame-pointer.
> (CFLAGS-mmap.c): Likewise.
> (CFLAGS-mmap64.c): Likewise.
> (CFLAGS-semtimedop.c): Likewise.
> * sysdeps/unix/sysv/linux/i386/mmap.c: New file.
> * sysdeps/unix/sysv/linux/i386/epoll_pwait.S: Remove file.
> * sysdeps/unix/sysv/linux/i386/mmap.S: Likewise.
> * sysdeps/unix/sysv/linux/i386/mmap64.S: Likewise.
> * sysdeps/unix/sysv/linux/i386/semtimedop.S: Likewise.
3 of 6 patches have been checked in. Here is the updated patch.
OK for master?
Thanks.
From aa65e03df89596fef1d249573779692681f638a6 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 12 Aug 2015 12:10:06 -0700
Subject: [PATCH 3/3] i386: Remove syscall assembly codes with 6 arguments
This patch removes i386 assembly implementation for epoll_wait, mmap,
mmap64, semtimeop now that i386 have 6 argument syscall support from
C code and GCC 5 can inline syscalls with 6 argument. We also compile
epoll_pwait.c, mmap.c, mmap64.c and semtimedop.c with -fomit-frame-pointer
since %ebp may be used to pass the 6th argument to syscall.
Fo sysdeps/unix/sysv/linux/i386/mmap.c, with -O2 -march=i686
-mtune=generic, GCC 5.2 now generates:
<__mmap>:
0: sub $0x10,%esp
3: mov 0x28(%esp),%eax
7: mov %ebx,(%esp)
a: mov 0x18(%esp),%ecx
e: mov %esi,0x4(%esp)
12: mov 0x14(%esp),%ebx
16: mov %edi,0x8(%esp)
1a: mov 0x1c(%esp),%edx
1e: test $0xfff,%eax
23: mov 0x20(%esp),%esi
27: mov %ebp,0xc(%esp)
2b: mov 0x24(%esp),%edi
2f: jne 60 <__mmap+0x60>
31: shr $0xc,%eax
34: mov %eax,%ebp
36: mov $0xc0,%eax
3b: call *%gs:0x10
42: cmp $0xfffff000,%eax
47: ja 65 <__mmap+0x65>
49: mov (%esp),%ebx
4c: mov 0x4(%esp),%esi
50: mov 0x8(%esp),%edi
54: mov 0xc(%esp),%ebp
58: add $0x10,%esp
5b: ret
5c: lea 0x0(%esi,%eiz,1),%esi
60: mov $0xffffffea,%eax
65: mov (%esp),%ebx
68: mov 0x4(%esp),%esi
6c: mov 0x8(%esp),%edi
70: mov 0xc(%esp),%ebp
74: add $0x10,%esp
77: jmp 78 <__mmap+0x78>
vs sysdeps/unix/sysv/linux/i386/mmap.S:
<__mmap>:
0: push %ebp
1: push %ebx
2: push %esi
3: push %edi
4: mov 0x14(%esp),%ebx
8: mov 0x18(%esp),%ecx
c: mov 0x1c(%esp),%edx
10: mov 0x20(%esp),%esi
14: mov 0x24(%esp),%edi
18: mov 0x28(%esp),%ebp
1c: test $0xfff,%ebp
22: mov $0xffffffea,%eax
27: jne 38 <__mmap+0x38>
29: shr $0xc,%ebp
2c: mov $0xc0,%eax
31: call *%gs:0x10
38: pop %edi
39: pop %esi
3a: pop %ebx
3b: pop %ebp
3c: cmp $0xfffff000,%eax
41: ja 44 <__mmap+0x44>
43: ret
44: call 45 <__mmap+0x45> 45: R_386_PC32 __x86.get_pc_thunk.cx
49: add $0x2,%ecx 4b: R_386_GOTPC _GLOBAL_OFFSET_TABLE_
4f: mov 0x0(%ecx),%ecx 51: R_386_TLS_GOTIE __libc_errno
55: neg %eax
57: mov %eax,%gs:(%ecx)
5a: or $0xffffffff,%eax
5d: ret
The C version has:
3: mov 0x28(%esp),%eax
...
1e: test $0xfff,%eax
...
31: sar $0xc,%eax
34: mov %eax,%ebp
is due to missing $ebx register constraint for inline asm. We have
to use "r" constraint with
register unsigned int _a6 asm ("ebp") = (unsigned int) (arg6);
and compiler chose %eax for offset (arg6) in
if (offset & (MMAP_PAGE_UNIT - 1))
* sysdeps/unix/sysv/linux/i386/Makefile (CFLAGS-epoll_pwait.c):
Add -fomit-frame-pointer.
(CFLAGS-mmap.c): Likewise.
(CFLAGS-mmap64.c): Likewise.
(CFLAGS-semtimedop.c): Likewise.
* sysdeps/unix/sysv/linux/i386/mmap.c: New file.
* sysdeps/unix/sysv/linux/i386/epoll_pwait.S: Remove file.
* sysdeps/unix/sysv/linux/i386/mmap.S: Likewise.
* sysdeps/unix/sysv/linux/i386/mmap64.S: Likewise.
* sysdeps/unix/sysv/linux/i386/semtimedop.S: Likewise.
---
sysdeps/unix/sysv/linux/i386/Makefile | 9 +++
sysdeps/unix/sysv/linux/i386/epoll_pwait.S | 78 -------------------
sysdeps/unix/sysv/linux/i386/mmap.S | 79 --------------------
sysdeps/unix/sysv/linux/i386/mmap.c | 36 +++++++++
sysdeps/unix/sysv/linux/i386/mmap64.S | 116 -----------------------------
sysdeps/unix/sysv/linux/i386/semtimedop.S | 73 ------------------
6 files changed, 45 insertions(+), 346 deletions(-)
delete mode 100644 sysdeps/unix/sysv/linux/i386/epoll_pwait.S
delete mode 100644 sysdeps/unix/sysv/linux/i386/mmap.S
create mode 100644 sysdeps/unix/sysv/linux/i386/mmap.c
delete mode 100644 sysdeps/unix/sysv/linux/i386/mmap64.S
delete mode 100644 sysdeps/unix/sysv/linux/i386/semtimedop.S
@@ -3,6 +3,15 @@ default-abi := 32
ifeq ($(subdir),misc)
sysdep_routines += ioperm iopl vm86
+# %ebp may be used to pass the 6th argument to syscall.
+CFLAGS-epoll_pwait.c += -fomit-frame-pointer
+CFLAGS-mmap.c += -fomit-frame-pointer
+CFLAGS-mmap64.c += -fomit-frame-pointer
+endif
+
+ifeq ($(subdir),sysvipc)
+# %ebp may be used to pass the 6th argument to syscall.
+CFLAGS-semtimedop.c += -fomit-frame-pointer
endif
ifeq ($(subdir),elf)
deleted file mode 100644
@@ -1,78 +0,0 @@
-/* Copyright (C) 2007-2015 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>
-#define _ERRNO_H
-#include <bits/errno.h>
-#define _SIGNAL_H
-#include <bits/signum.h>
-
-
- .text
-ENTRY (epoll_pwait)
-
-#ifdef __NR_epoll_pwait
-
- /* Save registers. */
- pushl %ebp
- cfi_adjust_cfa_offset (4)
- pushl %ebx
- cfi_adjust_cfa_offset (4)
- pushl %esi
- cfi_adjust_cfa_offset (4)
- pushl %edi
- cfi_adjust_cfa_offset (4)
- cfi_rel_offset (edi, 0)
- cfi_rel_offset (esi, 4)
- cfi_rel_offset (ebx, 8)
- cfi_rel_offset (ebp, 12)
-
- movl 20(%esp), %ebx
- movl 24(%esp), %ecx
- movl 28(%esp), %edx
- movl 32(%esp), %esi
- movl 36(%esp), %edi
- movl $_NSIG/8, %ebp
- movl $__NR_epoll_pwait, %eax
-
- ENTER_KERNEL
-
- /* Restore registers. */
- popl %edi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (edi)
- popl %esi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (esi)
- popl %ebx
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebx)
- popl %ebp
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebp)
-
- /* If 0 > %eax > -4096 there was an error. */
- cmpl $-4096, %eax
- ja SYSCALL_ERROR_LABEL
-
- /* Successful; return the syscall's value. */
-#else
- movl $-ENOSYS, %eax
- jmp SYSCALL_ERROR_LABEL
-#endif
- ret
-PSEUDO_END (epoll_pwait)
deleted file mode 100644
@@ -1,79 +0,0 @@
-/* Copyright (C) 1995-2015 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>
-
-#define EINVAL 22
-
- .text
-
-ENTRY (__mmap)
-
- /* Save registers. */
- pushl %ebp
- cfi_adjust_cfa_offset (4)
- pushl %ebx
- cfi_adjust_cfa_offset (4)
- pushl %esi
- cfi_adjust_cfa_offset (4)
- pushl %edi
- cfi_adjust_cfa_offset (4)
-
- movl 20(%esp), %ebx
- cfi_rel_offset (ebx, 8)
- movl 24(%esp), %ecx
- movl 28(%esp), %edx
- movl 32(%esp), %esi
- cfi_rel_offset (esi, 4)
- movl 36(%esp), %edi
- cfi_rel_offset (edi, 0)
- movl 40(%esp), %ebp
- cfi_rel_offset (ebp, 12)
- testl $0xfff, %ebp
- movl $-EINVAL, %eax
- jne L(skip)
- shrl $12, %ebp /* mmap2 takes the offset in pages. */
-
- movl $SYS_ify(mmap2), %eax /* System call number in %eax. */
-
- /* Do the system call trap. */
- ENTER_KERNEL
-L(skip):
- /* Restore registers. */
- popl %edi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (edi)
- popl %esi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (esi)
- popl %ebx
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebx)
- popl %ebp
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebp)
-
- /* If 0 > %eax > -4096 there was an error. */
- cmpl $-4096, %eax
- ja SYSCALL_ERROR_LABEL
-
- /* Successful; return the syscall's value. */
- ret
-
-PSEUDO_END (__mmap)
-
-weak_alias (__mmap, mmap)
new file mode 100644
@@ -0,0 +1,36 @@
+/* Copyright (C) 2015 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 <sys/types.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include <sysdep.h>
+
+#ifndef MMAP_PAGE_UNIT
+# define MMAP_PAGE_UNIT 4096UL
+#endif
+
+__ptr_t
+__mmap (__ptr_t addr, size_t len, int prot, int flags, int fd, off_t offset)
+{
+ if (offset & (MMAP_PAGE_UNIT - 1))
+ return (__ptr_t) INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
+ return (__ptr_t) INLINE_SYSCALL (mmap2, 6, addr, len, prot, flags, fd,
+ offset / MMAP_PAGE_UNIT);
+}
+
+weak_alias (__mmap, mmap)
deleted file mode 100644
@@ -1,116 +0,0 @@
-/* Copyright (C) 1995-2015 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>
-
-#define EINVAL 22
-#define ENOSYS 38
-
-#define SVRSP 16 /* saved register space */
-#define PARMS 4+SVRSP /* space for 4 saved regs */
-#define ADDR PARMS
-#define LEN ADDR+4
-#define PROT LEN+4
-#define FLAGS PROT+4
-#define FD FLAGS+4
-#define OFFLO FD+4
-#define OFFHI OFFLO+4
-
- .text
-ENTRY (__mmap64)
-
- /* Save registers. */
- pushl %ebp
- cfi_adjust_cfa_offset (4)
- pushl %ebx
- cfi_adjust_cfa_offset (4)
- pushl %esi
- cfi_adjust_cfa_offset (4)
- pushl %edi
- cfi_adjust_cfa_offset (4)
-
- movl OFFLO(%esp), %edx
- movl OFFHI(%esp), %ecx
- testl $0xfff, %edx
- jne L(einval)
- shrdl $12, %ecx, %edx /* mmap2 takes the offset in pages. */
- shrl $12, %ecx
- jne L(einval)
- movl %edx, %ebp
- cfi_rel_offset (ebp, 12)
-
- movl ADDR(%esp), %ebx
- cfi_rel_offset (ebx, 8)
- movl LEN(%esp), %ecx
- movl PROT(%esp), %edx
- movl FLAGS(%esp), %esi
- cfi_rel_offset (esi, 4)
- movl FD(%esp), %edi
- cfi_rel_offset (edi, 0)
-
- movl $SYS_ify(mmap2), %eax /* System call number in %eax. */
-
- /* Do the system call trap. */
-L(do_syscall):
- ENTER_KERNEL
-
- /* Restore registers. */
- popl %edi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (edi)
- popl %esi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (esi)
- popl %ebx
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebx)
- popl %ebp
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebp)
-
- /* If 0 > %eax > -4096 there was an error. */
- cmpl $-4096, %eax
- ja SYSCALL_ERROR_LABEL
-
- /* Successful; return the syscall's value. */
- ret
-
- cfi_adjust_cfa_offset (16)
- cfi_rel_offset (ebp, 12)
- cfi_rel_offset (ebx, 8)
- cfi_rel_offset (esi, 4)
- cfi_rel_offset (edi, 0)
- /* This means the offset value is too large. */
-L(einval):
- popl %edi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (edi)
- popl %esi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (esi)
- popl %ebx
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebx)
- popl %ebp
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebp)
- movl $-EINVAL, %eax
- jmp SYSCALL_ERROR_LABEL
-
-PSEUDO_END (__mmap64)
-
-weak_alias (__mmap64, mmap64)
deleted file mode 100644
@@ -1,73 +0,0 @@
-/* Copyright (C) 2003-2015 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
-
- 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>
-
-#define SYSOP_semtimedop 4
-
-#define SVRSP 12 /* saved register space */
-#define PARMS 4+SVRSP /* space for 3 saved regs */
-#define SEMID PARMS
-#define SOPS SEMID+4
-#define NSOPS SOPS+4
-#define TIMEOUT NSOPS+4
-
- .text
-ENTRY (semtimedop)
-
- pushl %ebp
- cfi_adjust_cfa_offset (4)
- pushl %ebx
- cfi_adjust_cfa_offset (4)
- pushl %edi
- cfi_adjust_cfa_offset (4)
-
- movl $SYSOP_semtimedop, %ebx
- cfi_rel_offset (ebx, 4)
- movl SEMID(%esp), %ecx
- movl NSOPS(%esp), %edx
- movl SOPS(%esp), %edi
- cfi_rel_offset (edi, 0)
- movl TIMEOUT(%esp), %ebp
- cfi_rel_offset (ebp, 8)
- movl $__NR_ipc, %eax
-
- ENTER_KERNEL
-
- /* Restore registers. */
- popl %edi
- cfi_adjust_cfa_offset (-4)
- cfi_restore (edi)
- popl %ebx
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebx)
- popl %ebp
- cfi_adjust_cfa_offset (-4)
- cfi_restore (ebp)
-
- /* If 0 > %eax > -4096 there was an error. */
- cmpl $-4096, %eax
- ja SYSCALL_ERROR_LABEL
-
- /* Successful; return the syscall's value. */
- ret
-
-#ifdef PIC
- .align 4
-#endif
-PSEUDO_END (semtimedop)
--
2.4.3