| /* 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 |
| |
| /* There is some commonality. */ |
| #include <sysdeps/unix/i386/sysdep.h> |
| #include <bp-sym.h> |
| #include <bp-asm.h> |
| /* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO. */ |
| #include <dl-sysdep.h> |
| #include <tls.h> |
| |
| |
| /* 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 |
| |
| # if 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); \ |
| PUSH_ERRNO_LOCATION_RETURN; \ |
| call BP_SYM (__errno_location)@PLT; \ |
| POP_ERRNO_LOCATION_RETURN; \ |
| 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): |
| |
| #else /* !__ASSEMBLER__ */ |
| |
| /* We need some help from the assembler to generate optimal code. We |
| define some macros here which later will be used. */ |
| asm (".L__X'%ebx = 1\n\t" |
| ".L__X'%ecx = 2\n\t" |
| ".L__X'%edx = 2\n\t" |
| ".L__X'%eax = 3\n\t" |
| ".L__X'%esi = 3\n\t" |
| ".L__X'%edi = 3\n\t" |
| ".L__X'%ebp = 3\n\t" |
| ".L__X'%esp = 3\n\t" |
| ".macro bpushl name reg\n\t" |
| ".if 1 - \\name\n\t" |
| ".if 2 - \\name\n\t" |
| "error\n\t" |
| ".else\n\t" |
| "xchgl \\reg, %ebx\n\t" |
| ".endif\n\t" |
| ".endif\n\t" |
| ".endm\n\t" |
| ".macro bpopl name reg\n\t" |
| ".if 1 - \\name\n\t" |
| ".if 2 - \\name\n\t" |
| "error\n\t" |
| ".else\n\t" |
| "xchgl \\reg, %ebx\n\t" |
| ".endif\n\t" |
| ".endif\n\t" |
| ".endm\n\t"); |
| |
| /* Define a macro which expands inline into the wrapper code for a system |
| call. */ |
| #undef INLINE_SYSCALL |
| #define INLINE_SYSCALL(name, nr, args...) \ |
| ({ \ |
| unsigned int resultvar = INTERNAL_SYSCALL (name, , nr, args); \ |
| if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0)) \ |
| { \ |
| __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \ |
| resultvar = 0xffffffff; \ |
| } \ |
| (int) resultvar; }) |
| |
| /* Define a macro which expands inline into the wrapper code for a system |
| call. This use is for internal calls that do not need to handle errors |
| normally. It will never touch errno. This returns just what the kernel |
| gave back. |
| |
| The _NCS variant allows non-constant syscall numbers but it is not |
| possible to use more than four parameters. */ |
| #undef INTERNAL_SYSCALL |
| #ifdef I386_USE_SYSENTER |
| # ifdef SHARED |
| # define INTERNAL_SYSCALL(name, err, nr, args...) \ |
| ({ \ |
| register unsigned int resultvar; \ |
| EXTRAVAR_##nr \ |
| asm volatile ( \ |
| LOADARGS_##nr \ |
| "movl %1, %%eax\n\t" \ |
| "call *%%gs:%P2\n\t" \ |
| RESTOREARGS_##nr \ |
| : "=a" (resultvar) \ |
| : "i" (__NR_##name), "i" (offsetof (tcbhead_t, sysinfo)) \ |
| ASMFMT_##nr(args) : "memory", "cc"); \ |
| (int) resultvar; }) |
| # define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \ |
| ({ \ |
| register unsigned int resultvar; \ |
| EXTRAVAR_##nr \ |
| asm volatile ( \ |
| LOADARGS_##nr \ |
| "call *%%gs:%P2\n\t" \ |
| RESTOREARGS_##nr \ |
| : "=a" (resultvar) \ |
| : "0" (name), "i" (offsetof (tcbhead_t, sysinfo)) \ |
| ASMFMT_##nr(args) : "memory", "cc"); \ |
| (int) resultvar; }) |
| # else |
| # define INTERNAL_SYSCALL(name, err, nr, args...) \ |
| ({ \ |
| register unsigned int resultvar; \ |
| EXTRAVAR_##nr \ |
| asm volatile ( \ |
| LOADARGS_##nr \ |
| "movl %1, %%eax\n\t" \ |
| "call *_dl_sysinfo\n\t" \ |
| RESTOREARGS_##nr \ |
| : "=a" (resultvar) \ |
| : "i" (__NR_##name) ASMFMT_##nr(args) : "memory", "cc"); \ |
| (int) resultvar; }) |
| # define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \ |
| ({ \ |
| register unsigned int resultvar; \ |
| EXTRAVAR_##nr \ |
| asm volatile ( \ |
| LOADARGS_##nr \ |
| "call *_dl_sysinfo\n\t" \ |
| RESTOREARGS_##nr \ |
| : "=a" (resultvar) \ |
| : "0" (name) ASMFMT_##nr(args) : "memory", "cc"); \ |
| (int) resultvar; }) |
| # endif |
| #else |
| # define INTERNAL_SYSCALL(name, err, nr, args...) \ |
| ({ \ |
| register unsigned int resultvar; \ |
| EXTRAVAR_##nr \ |
| asm volatile ( \ |
| LOADARGS_##nr \ |
| "movl %1, %%eax\n\t" \ |
| "int $0x80\n\t" \ |
| RESTOREARGS_##nr \ |
| : "=a" (resultvar) \ |
| : "i" (__NR_##name) ASMFMT_##nr(args) : "memory", "cc"); \ |
| (int) resultvar; }) |
| # define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \ |
| ({ \ |
| register unsigned int resultvar; \ |
| EXTRAVAR_##nr \ |
| asm volatile ( \ |
| LOADARGS_##nr \ |
| "int $0x80\n\t" \ |
| RESTOREARGS_##nr \ |
| : "=a" (resultvar) \ |
| : "0" (name) ASMFMT_##nr(args) : "memory", "cc"); \ |
| (int) resultvar; }) |
| #endif |
| |
| #undef INTERNAL_SYSCALL_DECL |
| #define INTERNAL_SYSCALL_DECL(err) do { } while (0) |
| |
| #undef INTERNAL_SYSCALL_ERROR_P |
| #define INTERNAL_SYSCALL_ERROR_P(val, err) \ |
| ((unsigned int) (val) >= 0xfffff001u) |
| |
| #undef INTERNAL_SYSCALL_ERRNO |
| #define INTERNAL_SYSCALL_ERRNO(val, err) (-(val)) |
| |
| #define LOADARGS_0 |
| #ifdef __PIC__ |
| # if defined I386_USE_SYSENTER && defined SHARED |
| # define LOADARGS_1 \ |
| "bpushl .L__X'%k3, %k3\n\t" |
| # define LOADARGS_5 \ |
| "movl %%ebx, %4\n\t" \ |
| "movl %3, %%ebx\n\t" |
| # else |
| # define LOADARGS_1 \ |
| "bpushl .L__X'%k2, %k2\n\t" |
| # define LOADARGS_5 \ |
| "movl %%ebx, %3\n\t" \ |
| "movl %2, %%ebx\n\t" |
| # endif |
| # define LOADARGS_2 LOADARGS_1 |
| # define LOADARGS_3 \ |
| "xchgl %%ebx, %%edi\n\t" |
| # define LOADARGS_4 LOADARGS_3 |
| #else |
| # define LOADARGS_1 |
| # define LOADARGS_2 |
| # define LOADARGS_3 |
| # define LOADARGS_4 |
| # define LOADARGS_5 |
| #endif |
| |
| #define RESTOREARGS_0 |
| #ifdef __PIC__ |
| # if defined I386_USE_SYSENTER && defined SHARED |
| # define RESTOREARGS_1 \ |
| "bpopl .L__X'%k3, %k3\n\t" |
| # define RESTOREARGS_5 \ |
| "movl %4, %%ebx" |
| # else |
| # define RESTOREARGS_1 \ |
| "bpopl .L__X'%k2, %k2\n\t" |
| # define RESTOREARGS_5 \ |
| "movl %3, %%ebx" |
| # endif |
| # define RESTOREARGS_2 RESTOREARGS_1 |
| # define RESTOREARGS_3 \ |
| "xchgl %%edi, %%ebx\n\t" |
| # define RESTOREARGS_4 RESTOREARGS_3 |
| #else |
| # define RESTOREARGS_1 |
| # define RESTOREARGS_2 |
| # define RESTOREARGS_3 |
| # define RESTOREARGS_4 |
| # define RESTOREARGS_5 |
| #endif |
| |
| #define ASMFMT_0() |
| #ifdef __PIC__ |
| # define ASMFMT_1(arg1) \ |
| , "cd" (arg1) |
| # define ASMFMT_2(arg1, arg2) \ |
| , "d" (arg1), "c" (arg2) |
| # define ASMFMT_3(arg1, arg2, arg3) \ |
| , "D" (arg1), "c" (arg2), "d" (arg3) |
| # define ASMFMT_4(arg1, arg2, arg3, arg4) \ |
| , "D" (arg1), "c" (arg2), "d" (arg3), "S" (arg4) |
| # define ASMFMT_5(arg1, arg2, arg3, arg4, arg5) \ |
| , "0" (arg1), "m" (_xv), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5) |
| #else |
| # define ASMFMT_1(arg1) \ |
| , "b" (arg1) |
| # define ASMFMT_2(arg1, arg2) \ |
| , "b" (arg1), "c" (arg2) |
| # define ASMFMT_3(arg1, arg2, arg3) \ |
| , "b" (arg1), "c" (arg2), "d" (arg3) |
| # define ASMFMT_4(arg1, arg2, arg3, arg4) \ |
| , "b" (arg1), "c" (arg2), "d" (arg3), "S" (arg4) |
| # define ASMFMT_5(arg1, arg2, arg3, arg4, arg5) \ |
| , "b" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5) |
| #endif |
| |
| #define EXTRAVAR_0 |
| #define EXTRAVAR_1 |
| #define EXTRAVAR_2 |
| #define EXTRAVAR_3 |
| #define EXTRAVAR_4 |
| #ifdef __PIC__ |
| # define EXTRAVAR_5 int _xv; |
| #else |
| # define EXTRAVAR_5 |
| #endif |
| |
| /* Consistency check for position-independent code. */ |
| #ifdef __PIC__ |
| # define check_consistency() \ |
| ({ int __res; \ |
| __asm__ __volatile__ \ |
| ("call __i686.get_pc_thunk.cx;" \ |
| "addl $_GLOBAL_OFFSET_TABLE_, %%ecx;" \ |
| "subl %%ebx, %%ecx;" \ |
| "je 1f;" \ |
| "ud2;" \ |
| "1:\n" \ |
| ".section .gnu.linkonce.t.__i686.get_pc_thunk.cx,\"ax\",@progbits;" \ |
| ".globl __i686.get_pc_thunk.cx;" \ |
| ".hidden __i686.get_pc_thunk.cx;" \ |
| ".type __i686.get_pc_thunk.cx,@function;" \ |
| "__i686.get_pc_thunk.cx:" \ |
| "movl (%%esp), %%ecx;" \ |
| "ret;" \ |
| ".previous" \ |
| : "=c" (__res)); \ |
| __res; }) |
| #endif |
| |
| #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 */ |
