diff options
Diffstat (limited to 'libc/sysdeps/linux/xtensa/vfork.S')
| -rw-r--r-- | libc/sysdeps/linux/xtensa/vfork.S | 137 |
1 files changed, 80 insertions, 57 deletions
diff --git a/libc/sysdeps/linux/xtensa/vfork.S b/libc/sysdeps/linux/xtensa/vfork.S index 830a0cd4d..8058fb057 100644 --- a/libc/sysdeps/linux/xtensa/vfork.S +++ b/libc/sysdeps/linux/xtensa/vfork.S @@ -1,4 +1,4 @@ -/* Copyright (C) 2005, 2007 Free Software Foundation, Inc. +/* Copyright (C) 2005-2013 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 @@ -12,80 +12,78 @@ 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., 51 Franklin Street - Fifth Floor, - Boston, MA 02110-1301, USA. */ + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ #include "sysdep.h" #include <sys/syscall.h> #define _SIGNAL_H #include <bits/signum.h> +#define __ASSEMBLY__ +#include <linux/sched.h> -/* Clone the calling process, but without copying the whole address space. +/* + Clone the calling process, but without copying the whole address space. The calling process is suspended until the new process exits or is replaced by a call to `execve'. Return -1 for errors, 0 to the new process, and the process ID of the new process to the old process. Note that it is important that we don't create a new stack frame for the - caller. */ + caller. - -/* The following are defined in linux/sched.h, which unfortunately - is not safe for inclusion in an assembly file. */ -#define CLONE_VM 0x00000100 /* set if VM shared between processes */ -#define CLONE_VFORK 0x00004000 /* set if the parent wants the child to - wake it up on mm_release */ +*/ #ifndef SAVE_PID -#define SAVE_PID +#define SAVE_PID(a,b,c,d) #endif - #ifndef RESTORE_PID -#define RESTORE_PID +#define RESTORE_PID(a,b,c) +#endif +#ifndef RESTORE_PID12 +#define RESTORE_PID12(a,b,c) #endif +/* + pid_t vfork(void); + Implemented as __clone_syscall(CLONE_VFORK | CLONE_VM | SIGCHLD, 0) + */ -/* pid_t vfork(void); - Implemented as __clone_syscall(CLONE_VFORK | CLONE_VM | SIGCHLD, 0) */ -ENTRY (__vfork) +HIDDEN_ENTRY (__vfork) - movi a6, .Ljumptable - extui a2, a0, 30, 2 // call-size: call4/8/12 = 1/2/3 - addx4 a4, a2, a6 // find return address in jumptable - l32i a4, a4, 0 - add a4, a4, a6 +#if defined(__XTENSA_WINDOWED_ABI__) + .literal .Ljumptable, 0, .L4, .L8, .L12 + mov a3, a0 # move return address out of the way + movi a0, .Ljumptable + extui a2, a3, 30, 2 # call-size: call4/8/12 = 1/2/3 + addx4 a0, a2, a0 # find return address in jumptable + l32i a0, a0, 0 + # exchange top 2 bits of a0 and a3: + xor a2, a0, a3 + extui a2, a2, 30, 2 slli a2, a2, 30 - xor a3, a0, a2 // remove call-size from return address - extui a5, a4, 30, 2 // get high bits of jump target - slli a5, a5, 30 - or a3, a3, a5 // stuff them into the return address - xor a4, a4, a5 // clear high bits of jump target - or a0, a4, a2 // create temporary return address - retw // "return" to .L4, .L8, or .L12 - - .align 4 -.Ljumptable: - .word 0 - .word .L4 - .Ljumptable - .word .L8 - .Ljumptable - .word .L12 - .Ljumptable + xor a0, a0, a2 + xor a3, a3, a2 + retw /* a7: return address */ + .L4: mov a12, a2 mov a13, a3 - SAVE_PID + SAVE_PID(a5,a15,a2,a3) - /* Use syscall 'clone'. Set new stack pointer to the same address. */ - movi a2, SYS_ify (clone) - movi a3, 0 + /* use syscall 'clone' and set new stack pointer to the same address */ + + movi a2, SYS_ify(clone) + movi a3, 0 movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD + syscall - RESTORE_PID + RESTORE_PID(a5,a15,a2) movi a5, -4096 @@ -95,22 +93,24 @@ ENTRY (__vfork) bgeu a6, a5, 1f jx a7 -1: call4 .Lerr // returns to original caller +1: call4 .Lerr /* a11: return address */ + .L8: mov a12, a2 mov a13, a3 mov a14, a6 - SAVE_PID + SAVE_PID(a9,a15,a2,a3) - movi a2, SYS_ify (clone) + movi a2, SYS_ify(clone) movi a3, 0 movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD + syscall - RESTORE_PID + RESTORE_PID(a9,a15,a2) movi a9, -4096 @@ -121,22 +121,25 @@ ENTRY (__vfork) bgeu a10, a9, 1f jx a11 -1: call8 .Lerr // returns to original caller + +1: call8 .Lerr /* a15: return address */ + .L12: mov a12, a2 mov a13, a3 mov a14, a6 - SAVE_PID + SAVE_PID (a2,a3,a2,a6) - movi a2, SYS_ify (clone) + movi a2, SYS_ify(clone) movi a3, 0 movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD + syscall - RESTORE_PID + RESTORE_PID12(a3,a6,a15) mov a3, a13 movi a13, -4096 @@ -148,23 +151,43 @@ ENTRY (__vfork) bgeu a14, a13, 1f jx a15 -1: call12 .Lerr // returns to original caller +1: call12 .Lerr .align 4 + .Lerr: entry a1, 16 - /* Restore the return address. */ - extui a4, a0, 30, 2 // get the call-size bits + /* Restore return address */ + + extui a4, a0, 30, 2 slli a4, a4, 30 - slli a3, a3, 2 // clear high bits of target address - srli a3, a3, 2 - or a0, a3, a4 // combine them + or a0, a3, a4 PSEUDO_END (__vfork) .Lpseudo_end: retw +#elif defined(__XTENSA_CALL0_ABI__) + SAVE_PID(a5, a8, a3, a4) + + /* Use syscall 'clone'. Set new stack pointer to the same address. */ + movi a2, SYS_ify (clone) + movi a3, 0 + movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD + syscall + + RESTORE_PID(a5, a8, a2) -libc_hidden_def (__vfork) + movi a3, -4096 + bgeu a2, a3, 1f + ret +1: + PSEUDO_END (__vfork) +.Lpseudo_end: + ret +#else +#error Unsupported Xtensa ABI +#endif weak_alias (__vfork, vfork) +libc_hidden_def(vfork) |