diff options
Diffstat (limited to 'libc/sysdeps/linux/metag/clone.S')
| -rw-r--r-- | libc/sysdeps/linux/metag/clone.S | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/metag/clone.S b/libc/sysdeps/linux/metag/clone.S new file mode 100644 index 000000000..8fff56710 --- /dev/null +++ b/libc/sysdeps/linux/metag/clone.S @@ -0,0 +1,65 @@ +! Copyright (C) 2013 Imagination Technologies Ltd. + +! Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball. + +! clone() is even more special than fork() as it mucks with stacks +! and invokes a function in the right context after its all over. + +#include <asm/errno.h> +#include <asm/unistd.h> + +/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */ + + .text + .global __clone + .type __clone,function +__clone: + ! sanity check args + MOV D0Re0, #-EINVAL + CMP D1Ar1, #0 + BEQ ___error + CMP D0Ar2, #0 + BEQ ___error + + ! save function pointer + MOV D0FrT, D1Ar1 + + ! do the system call + ! get flags + MOV D1Ar1, D1Ar3 + ! new sp is already in D0Ar2 + MOV D1Re0, #__NR_clone + SWITCH #0x440001 + CMP D0Re0,#0 + ! Error on -1 + BLT ___error + ! If non-zero we are the parent + MOVNE PC, D1RtP + ! BRKPNT + + ! We are the child + ! pick the function arg and call address off the stack and execute + MOV D0Ar2, D0FrT + MOV D1Ar1, D0Ar4 + MOV D1RtP, PC + ADD D1RtP, D1RtP, #8 + MOV PC, D0Ar2 + + ! and we are done, passing the return value through D0Re0 +#ifdef __PIC__ + B _exit@PLT +#else + B _exit +#endif + +___error: + MOV D1Ar1, D0Re0 +#ifdef __PIC__ + B ___syscall_error@PLT +#else + B ___syscall_error +#endif + .size __clone, .-__clone + +.weak _clone +_clone = __clone |