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-rw-r--r--libc/sysdeps/linux/i386/sysdep.h336
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diff --git a/libc/sysdeps/linux/i386/sysdep.h b/libc/sysdeps/linux/i386/sysdep.h
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+++ b/libc/sysdeps/linux/i386/sysdep.h
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+/* Copyright (C) 1992,1993,1995-2000,2002-2006,2007
+ Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper, <drepper@gnu.org>, August 1995.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _LINUX_I386_SYSDEP_H
+#define _LINUX_I386_SYSDEP_H 1
+
+#include <sys/syscall.h>
+#include <sysdeps/i386/sysdep.h>
+
+#ifndef offsetof
+# define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
+#endif
+
+/* For Linux we can use the system call table in the header file
+ /usr/include/asm/unistd.h
+ of the kernel. But these symbols do not follow the SYS_* syntax
+ so we have to redefine the `SYS_ify' macro here. */
+#undef SYS_ify
+#define SYS_ify(syscall_name) __NR_##syscall_name
+
+#if defined USE_DL_SYSINFO \
+ && (!defined NOT_IN_libc || defined IS_IN_libpthread)
+# define I386_USE_SYSENTER 1
+#else
+# undef I386_USE_SYSENTER
+#endif
+
+#ifdef __ASSEMBLER__
+
+/* Linux uses a negative return value to indicate syscall errors,
+ unlike most Unices, which use the condition codes' carry flag.
+
+ Since version 2.1 the return value of a system call might be
+ negative even if the call succeeded. E.g., the `lseek' system call
+ might return a large offset. Therefore we must not anymore test
+ for < 0, but test for a real error by making sure the value in %eax
+ is a real error number. Linus said he will make sure the no syscall
+ returns a value in -1 .. -4095 as a valid result so we can savely
+ test with -4095. */
+
+/* We don't want the label for the error handle to be global when we define
+ it here. */
+#ifdef __PIC__
+# define SYSCALL_ERROR_LABEL 0f
+#else
+# define SYSCALL_ERROR_LABEL syscall_error
+#endif
+
+#undef PSEUDO
+#define PSEUDO(name, syscall_name, args) \
+ .text; \
+ ENTRY (name) \
+ DO_CALL (syscall_name, args); \
+ cmpl $-4095, %eax; \
+ jae SYSCALL_ERROR_LABEL; \
+ L(pseudo_end):
+
+#undef PSEUDO_END
+#define PSEUDO_END(name) \
+ SYSCALL_ERROR_HANDLER \
+ END (name)
+
+#undef PSEUDO_NOERRNO
+#define PSEUDO_NOERRNO(name, syscall_name, args) \
+ .text; \
+ ENTRY (name) \
+ DO_CALL (syscall_name, args)
+
+#undef PSEUDO_END_NOERRNO
+#define PSEUDO_END_NOERRNO(name) \
+ END (name)
+
+#define ret_NOERRNO ret
+
+/* The function has to return the error code. */
+#undef PSEUDO_ERRVAL
+#define PSEUDO_ERRVAL(name, syscall_name, args) \
+ .text; \
+ ENTRY (name) \
+ DO_CALL (syscall_name, args); \
+ negl %eax
+
+#undef PSEUDO_END_ERRVAL
+#define PSEUDO_END_ERRVAL(name) \
+ END (name)
+
+#define ret_ERRVAL ret
+
+#ifndef __PIC__
+# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
+#else
+
+# ifdef RTLD_PRIVATE_ERRNO
+# define SYSCALL_ERROR_HANDLER \
+0:SETUP_PIC_REG(cx); \
+ addl $_GLOBAL_OFFSET_TABLE_, %ecx; \
+ xorl %edx, %edx; \
+ subl %eax, %edx; \
+ movl %edx, rtld_errno@GOTOFF(%ecx); \
+ orl $-1, %eax; \
+ jmp L(pseudo_end);
+
+# elif defined _LIBC_REENTRANT
+
+# if USE___THREAD
+# ifndef NOT_IN_libc
+# define SYSCALL_ERROR_ERRNO __libc_errno
+# else
+# define SYSCALL_ERROR_ERRNO errno
+# endif
+# define SYSCALL_ERROR_HANDLER \
+0:SETUP_PIC_REG (cx); \
+ addl $_GLOBAL_OFFSET_TABLE_, %ecx; \
+ movl SYSCALL_ERROR_ERRNO@GOTNTPOFF(%ecx), %ecx; \
+ xorl %edx, %edx; \
+ subl %eax, %edx; \
+ SYSCALL_ERROR_HANDLER_TLS_STORE (%edx, %ecx); \
+ orl $-1, %eax; \
+ jmp L(pseudo_end);
+# ifndef NO_TLS_DIRECT_SEG_REFS
+# define SYSCALL_ERROR_HANDLER_TLS_STORE(src, destoff) \
+ movl src, %gs:(destoff)
+# else
+# define SYSCALL_ERROR_HANDLER_TLS_STORE(src, destoff) \
+ addl %gs:0, destoff; \
+ movl src, (destoff)
+# endif
+# else
+# define SYSCALL_ERROR_HANDLER \
+0:pushl %ebx; \
+ cfi_adjust_cfa_offset (4); \
+ cfi_rel_offset (ebx, 0); \
+ SETUP_PIC_REG (bx); \
+ addl $_GLOBAL_OFFSET_TABLE_, %ebx; \
+ xorl %edx, %edx; \
+ subl %eax, %edx; \
+ pushl %edx; \
+ cfi_adjust_cfa_offset (4); \
+ call __errno_location@PLT; \
+ popl %ecx; \
+ cfi_adjust_cfa_offset (-4); \
+ popl %ebx; \
+ cfi_adjust_cfa_offset (-4); \
+ cfi_restore (ebx); \
+ movl %ecx, (%eax); \
+ orl $-1, %eax; \
+ jmp L(pseudo_end);
+/* A quick note: it is assumed that the call to `__errno_location' does
+ not modify the stack! */
+# endif
+# else
+/* Store (- %eax) into errno through the GOT. */
+# define SYSCALL_ERROR_HANDLER \
+0:SETUP_PIC_REG(cx); \
+ addl $_GLOBAL_OFFSET_TABLE_, %ecx; \
+ xorl %edx, %edx; \
+ subl %eax, %edx; \
+ movl errno@GOT(%ecx), %ecx; \
+ movl %edx, (%ecx); \
+ orl $-1, %eax; \
+ jmp L(pseudo_end);
+# endif /* _LIBC_REENTRANT */
+#endif /* __PIC__ */
+
+
+/* The original calling convention for system calls on Linux/i386 is
+ to use int $0x80. */
+#ifdef I386_USE_SYSENTER
+# ifdef SHARED
+# define ENTER_KERNEL call *%gs:SYSINFO_OFFSET
+# else
+# define ENTER_KERNEL call *_dl_sysinfo
+# endif
+#else
+# define ENTER_KERNEL int $0x80
+#endif
+
+/* Linux takes system call arguments in registers:
+
+ syscall number %eax call-clobbered
+ arg 1 %ebx call-saved
+ arg 2 %ecx call-clobbered
+ arg 3 %edx call-clobbered
+ arg 4 %esi call-saved
+ arg 5 %edi call-saved
+ arg 6 %ebp call-saved
+
+ The stack layout upon entering the function is:
+
+ 24(%esp) Arg# 6
+ 20(%esp) Arg# 5
+ 16(%esp) Arg# 4
+ 12(%esp) Arg# 3
+ 8(%esp) Arg# 2
+ 4(%esp) Arg# 1
+ (%esp) Return address
+
+ (Of course a function with say 3 arguments does not have entries for
+ arguments 4, 5, and 6.)
+
+ The following code tries hard to be optimal. A general assumption
+ (which is true according to the data books I have) is that
+
+ 2 * xchg is more expensive than pushl + movl + popl
+
+ Beside this a neat trick is used. The calling conventions for Linux
+ tell that among the registers used for parameters %ecx and %edx need
+ not be saved. Beside this we may clobber this registers even when
+ they are not used for parameter passing.
+
+ As a result one can see below that we save the content of the %ebx
+ register in the %edx register when we have less than 3 arguments
+ (2 * movl is less expensive than pushl + popl).
+
+ Second unlike for the other registers we don't save the content of
+ %ecx and %edx when we have more than 1 and 2 registers resp.
+
+ The code below might look a bit long but we have to take care for
+ the pipelined processors (i586). Here the `pushl' and `popl'
+ instructions are marked as NP (not pairable) but the exception is
+ two consecutive of these instruction. This gives no penalty on
+ other processors though. */
+
+#undef DO_CALL
+#define DO_CALL(syscall_name, args) \
+ PUSHARGS_##args \
+ DOARGS_##args \
+ movl $SYS_ify (syscall_name), %eax; \
+ ENTER_KERNEL \
+ POPARGS_##args
+
+#define PUSHARGS_0 /* No arguments to push. */
+#define DOARGS_0 /* No arguments to frob. */
+#define POPARGS_0 /* No arguments to pop. */
+#define _PUSHARGS_0 /* No arguments to push. */
+#define _DOARGS_0(n) /* No arguments to frob. */
+#define _POPARGS_0 /* No arguments to pop. */
+
+#define PUSHARGS_1 movl %ebx, %edx; L(SAVEBX1): PUSHARGS_0
+#define DOARGS_1 _DOARGS_1 (4)
+#define POPARGS_1 POPARGS_0; movl %edx, %ebx; L(RESTBX1):
+#define _PUSHARGS_1 pushl %ebx; cfi_adjust_cfa_offset (4); \
+ cfi_rel_offset (ebx, 0); L(PUSHBX1): _PUSHARGS_0
+#define _DOARGS_1(n) movl n(%esp), %ebx; _DOARGS_0(n-4)
+#define _POPARGS_1 _POPARGS_0; popl %ebx; cfi_adjust_cfa_offset (-4); \
+ cfi_restore (ebx); L(POPBX1):
+
+#define PUSHARGS_2 PUSHARGS_1
+#define DOARGS_2 _DOARGS_2 (8)
+#define POPARGS_2 POPARGS_1
+#define _PUSHARGS_2 _PUSHARGS_1
+#define _DOARGS_2(n) movl n(%esp), %ecx; _DOARGS_1 (n-4)
+#define _POPARGS_2 _POPARGS_1
+
+#define PUSHARGS_3 _PUSHARGS_2
+#define DOARGS_3 _DOARGS_3 (16)
+#define POPARGS_3 _POPARGS_3
+#define _PUSHARGS_3 _PUSHARGS_2
+#define _DOARGS_3(n) movl n(%esp), %edx; _DOARGS_2 (n-4)
+#define _POPARGS_3 _POPARGS_2
+
+#define PUSHARGS_4 _PUSHARGS_4
+#define DOARGS_4 _DOARGS_4 (24)
+#define POPARGS_4 _POPARGS_4
+#define _PUSHARGS_4 pushl %esi; cfi_adjust_cfa_offset (4); \
+ cfi_rel_offset (esi, 0); L(PUSHSI1): _PUSHARGS_3
+#define _DOARGS_4(n) movl n(%esp), %esi; _DOARGS_3 (n-4)
+#define _POPARGS_4 _POPARGS_3; popl %esi; cfi_adjust_cfa_offset (-4); \
+ cfi_restore (esi); L(POPSI1):
+
+#define PUSHARGS_5 _PUSHARGS_5
+#define DOARGS_5 _DOARGS_5 (32)
+#define POPARGS_5 _POPARGS_5
+#define _PUSHARGS_5 pushl %edi; cfi_adjust_cfa_offset (4); \
+ cfi_rel_offset (edi, 0); L(PUSHDI1): _PUSHARGS_4
+#define _DOARGS_5(n) movl n(%esp), %edi; _DOARGS_4 (n-4)
+#define _POPARGS_5 _POPARGS_4; popl %edi; cfi_adjust_cfa_offset (-4); \
+ cfi_restore (edi); L(POPDI1):
+
+#define PUSHARGS_6 _PUSHARGS_6
+#define DOARGS_6 _DOARGS_6 (40)
+#define POPARGS_6 _POPARGS_6
+#define _PUSHARGS_6 pushl %ebp; cfi_adjust_cfa_offset (4); \
+ cfi_rel_offset (ebp, 0); L(PUSHBP1): _PUSHARGS_5
+#define _DOARGS_6(n) movl n(%esp), %ebp; _DOARGS_5 (n-4)
+#define _POPARGS_6 _POPARGS_5; popl %ebp; cfi_adjust_cfa_offset (-4); \
+ cfi_restore (ebp); L(POPBP1):
+
+#endif /* __ASSEMBLER__ */
+
+
+/* Pointer mangling support. */
+#if defined NOT_IN_libc && defined IS_IN_rtld
+/* We cannot use the thread descriptor because in ld.so we use setjmp
+ earlier than the descriptor is initialized. Using a global variable
+ is too complicated here since we have no PC-relative addressing mode. */
+#else
+# ifdef __ASSEMBLER__
+# define PTR_MANGLE(reg) xorl %gs:POINTER_GUARD, reg; \
+ roll $9, reg
+# define PTR_DEMANGLE(reg) rorl $9, reg; \
+ xorl %gs:POINTER_GUARD, reg
+# else
+# define PTR_MANGLE(var) __asm__ ("xorl %%gs:%c2, %0\n" \
+ "roll $9, %0" \
+ : "=r" (var) \
+ : "0" (var), \
+ "i" (offsetof (tcbhead_t, \
+ pointer_guard)))
+# define PTR_DEMANGLE(var) __asm__ ("rorl $9, %0\n" \
+ "xorl %%gs:%c2, %0" \
+ : "=r" (var) \
+ : "0" (var), \
+ "i" (offsetof (tcbhead_t, \
+ pointer_guard)))
+# endif
+#endif
+
+#endif /* linux/i386/sysdep.h */