diff options
Diffstat (limited to 'libc/sysdeps/linux/xtensa/vfork.S')
| -rw-r--r-- | libc/sysdeps/linux/xtensa/vfork.S | 104 |
1 files changed, 52 insertions, 52 deletions
diff --git a/libc/sysdeps/linux/xtensa/vfork.S b/libc/sysdeps/linux/xtensa/vfork.S index f094ae38f..6aced0a50 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 @@ -19,72 +19,67 @@ #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) */ HIDDEN_ENTRY (__vfork) + .literal .Ljumptable, 0, .L4, .L8, .L12 - 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 - + 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 slli a2, a2, 30 - xor a3, a0, a2 /* remove call-size from return addr */ - 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 + l32i a0, a0, 0 + + xor a3, a3, a2 # remove call-size from return address + or a0, a0, a2 # create temporary return address + retw /* a7: return address */ + .L4: mov a12, a2 mov a13, a3 - SAVE_PID + SAVE_PID(a5,a15,a2,a3) + + /* use syscall 'clone' and set new stack pointer to the same address */ - /* Use syscall 'clone'. Set new stack pointer to the same address. */ - 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(a5,a15,a2) movi a5, -4096 @@ -94,22 +89,24 @@ HIDDEN_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 @@ -120,22 +117,25 @@ HIDDEN_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 @@ -147,18 +147,18 @@ HIDDEN_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: |