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-rw-r--r--libc/sysdeps/linux/x86_64/sysdep.h352
1 files changed, 352 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/x86_64/sysdep.h b/libc/sysdeps/linux/x86_64/sysdep.h
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--- /dev/null
+++ b/libc/sysdeps/linux/x86_64/sysdep.h
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+/* Copyright (C) 2001-2005, 2007 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _LINUX_X86_64_SYSDEP_H
+#define _LINUX_X86_64_SYSDEP_H 1
+
+/* There is some commonality. */
+#include <sys/syscall.h>
+#include <common/sysdep.h>
+
+#ifdef __ASSEMBLER__
+
+/* Syntactic details of assembler. */
+
+#ifdef HAVE_ELF
+
+/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
+#define ALIGNARG(log2) 1<<log2
+/* For ELF we need the `.type' directive to make shared libs work right. */
+#define ASM_TYPE_DIRECTIVE(name,typearg) .type name,typearg;
+#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
+
+/* In ELF C symbols are asm symbols. */
+#undef NO_UNDERSCORES
+#define NO_UNDERSCORES
+
+#else
+
+#define ALIGNARG(log2) log2
+#define ASM_TYPE_DIRECTIVE(name,type) /* Nothing is specified. */
+#define ASM_SIZE_DIRECTIVE(name) /* Nothing is specified. */
+
+#endif
+
+
+/* Define an entry point visible from C. */
+#define ENTRY(name) \
+ ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name); \
+ ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),@function) \
+ .align ALIGNARG(4); \
+ C_LABEL(name) \
+ cfi_startproc; \
+ CALL_MCOUNT
+
+#undef END
+#define END(name) \
+ cfi_endproc; \
+ ASM_SIZE_DIRECTIVE(name)
+
+/* If compiled for profiling, call `mcount' at the start of each function. */
+#ifdef PROF
+/* The mcount code relies on a normal frame pointer being on the stack
+ to locate our caller, so push one just for its benefit. */
+#define CALL_MCOUNT \
+ pushq %rbp; \
+ cfi_adjust_cfa_offset(8); \
+ movq %rsp, %rbp; \
+ cfi_def_cfa_register(%rbp); \
+ call JUMPTARGET(mcount); \
+ popq %rbp; \
+ cfi_def_cfa(rsp,8);
+#else
+#define CALL_MCOUNT /* Do nothing. */
+#endif
+
+#ifdef NO_UNDERSCORES
+/* Since C identifiers are not normally prefixed with an underscore
+ on this system, the asm identifier `syscall_error' intrudes on the
+ C name space. Make sure we use an innocuous name. */
+#define syscall_error __syscall_error
+#define mcount _mcount
+#endif
+
+#define PSEUDO(name, syscall_name, args) \
+lose: \
+ jmp JUMPTARGET(syscall_error) \
+ .globl syscall_error; \
+ ENTRY (name) \
+ DO_CALL (syscall_name, args); \
+ jb lose
+
+#undef PSEUDO_END
+#define PSEUDO_END(name) \
+ END (name)
+
+#undef JUMPTARGET
+#ifdef __PIC__
+#define JUMPTARGET(name) name##@PLT
+#else
+#define JUMPTARGET(name) name
+#endif
+
+/* Local label name for asm code. */
+#ifndef L
+# ifdef HAVE_ELF
+/* ELF-like local names start with `.L'. */
+# define L(name) .L##name
+# else
+# define L(name) name
+# endif
+#endif
+
+#endif /* __ASSEMBLER__ */
+#ifdef IS_IN_rtld
+# include <dl-sysdep.h> /* Defines RTLD_PRIVATE_ERRNO. */
+#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
+
+/* This is a kludge to make syscalls.list find these under the names
+ pread and pwrite, since some kernel headers define those names
+ and some define the *64 names for the same system calls. */
+#if !defined __NR_pread && defined __NR_pread64
+# define __NR_pread __NR_pread64
+#endif
+#if !defined __NR_pwrite && defined __NR_pwrite64
+# define __NR_pwrite __NR_pwrite64
+#endif
+
+/* This is to help the old kernel headers where __NR_semtimedop is not
+ available. */
+#ifndef __NR_semtimedop
+# define __NR_semtimedop 220
+#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); \
+ cmpq $-4095, %rax; \
+ 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
+
+# undef PSEUDO_ERRVAL
+# define PSEUDO_ERRVAL(name, syscall_name, args) \
+ .text; \
+ ENTRY (name) \
+ DO_CALL (syscall_name, args); \
+ negq %rax
+
+# 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. */
+# elif defined(RTLD_PRIVATE_ERRNO)
+# define SYSCALL_ERROR_HANDLER \
+0: \
+ leaq rtld_errno(%rip), %rcx; \
+ xorl %edx, %edx; \
+ subq %rax, %rdx; \
+ movl %edx, (%rcx); \
+ orq $-1, %rax; \
+ jmp L(pseudo_end);
+# elif USE___THREAD
+# ifndef NOT_IN_libc
+# define SYSCALL_ERROR_ERRNO __libc_errno
+# else
+# define SYSCALL_ERROR_ERRNO errno
+# endif
+# define SYSCALL_ERROR_HANDLER \
+0: \
+ movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
+ xorl %edx, %edx; \
+ subq %rax, %rdx; \
+ movl %edx, %fs:(%rcx); \
+ orq $-1, %rax; \
+ jmp L(pseudo_end);
+# elif defined _LIBC_REENTRANT
+/* Store (- %rax) into errno through the GOT.
+ Note that errno occupies only 4 bytes. */
+# define SYSCALL_ERROR_HANDLER \
+0: \
+ xorl %edx, %edx; \
+ subq %rax, %rdx; \
+ pushq %rdx; \
+ cfi_adjust_cfa_offset(8); \
+ call __errno_location@PLT; \
+ popq %rdx; \
+ cfi_adjust_cfa_offset(-8); \
+ movl %edx, (%rax); \
+ orq $-1, %rax; \
+ jmp L(pseudo_end);
+
+/* A quick note: it is assumed that the call to `__errno_location' does
+ not modify the stack! */
+# else /* Not _LIBC_REENTRANT. */
+# define SYSCALL_ERROR_HANDLER \
+0:movq errno@GOTPCREL(%RIP), %rcx; \
+ xorl %edx, %edx; \
+ subq %rax, %rdx; \
+ movl %edx, (%rcx); \
+ orq $-1, %rax; \
+ jmp L(pseudo_end);
+# endif /* __PIC__ */
+
+/* The Linux/x86-64 kernel expects the system call parameters in
+ registers according to the following table:
+
+ syscall number rax
+ arg 1 rdi
+ arg 2 rsi
+ arg 3 rdx
+ arg 4 r10
+ arg 5 r8
+ arg 6 r9
+
+ The Linux kernel uses and destroys internally these registers:
+ return address from
+ syscall rcx
+ eflags from syscall r11
+
+ Normal function call, including calls to the system call stub
+ functions in the libc, get the first six parameters passed in
+ registers and the seventh parameter and later on the stack. The
+ register use is as follows:
+
+ system call number in the DO_CALL macro
+ arg 1 rdi
+ arg 2 rsi
+ arg 3 rdx
+ arg 4 rcx
+ arg 5 r8
+ arg 6 r9
+
+ We have to take care that the stack is aligned to 16 bytes. When
+ called the stack is not aligned since the return address has just
+ been pushed.
+
+
+ Syscalls of more than 6 arguments are not supported. */
+
+# undef DO_CALL
+# define DO_CALL(syscall_name, args) \
+ DOARGS_##args \
+ movl $SYS_ify (syscall_name), %eax; \
+ syscall;
+
+# define DOARGS_0 /* nothing */
+# define DOARGS_1 /* nothing */
+# define DOARGS_2 /* nothing */
+# define DOARGS_3 /* nothing */
+# define DOARGS_4 movq %rcx, %r10;
+# define DOARGS_5 DOARGS_4
+# define DOARGS_6 DOARGS_5
+
+#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. */
+# ifdef __ASSEMBLER__
+# define PTR_MANGLE(reg) xorq __pointer_chk_guard_local(%rip), reg; \
+ rolq $17, reg
+# define PTR_DEMANGLE(reg) rorq $17, reg; \
+ xorq __pointer_chk_guard_local(%rip), reg
+# else
+# define PTR_MANGLE(reg) asm ("xorq __pointer_chk_guard_local(%%rip), %0\n" \
+ "rolq $17, %0" \
+ : "=r" (reg) : "0" (reg))
+# define PTR_DEMANGLE(reg) asm ("rorq $17, %0\n" \
+ "xorq __pointer_chk_guard_local(%%rip), %0" \
+ : "=r" (reg) : "0" (reg))
+# endif
+#else
+# ifdef __ASSEMBLER__
+# define PTR_MANGLE(reg) xorq %fs:POINTER_GUARD, reg; \
+ rolq $17, reg
+# define PTR_DEMANGLE(reg) rorq $17, reg; \
+ xorq %fs:POINTER_GUARD, reg
+# else
+# define PTR_MANGLE(var) asm ("xorq %%fs:%c2, %0\n" \
+ "rolq $17, %0" \
+ : "=r" (var) \
+ : "0" (var), \
+ "i" (offsetof (tcbhead_t, \
+ pointer_guard)))
+# define PTR_DEMANGLE(var) asm ("rorq $17, %0\n" \
+ "xorq %%fs:%c2, %0" \
+ : "=r" (var) \
+ : "0" (var), \
+ "i" (offsetof (tcbhead_t, \
+ pointer_guard)))
+# endif
+#endif
+
+#endif /* linux/x86_64/sysdep.h */