diff options
Diffstat (limited to 'libc/sysdeps/linux/hppa/clone.S')
| -rw-r--r-- | libc/sysdeps/linux/hppa/clone.S | 154 |
1 files changed, 91 insertions, 63 deletions
diff --git a/libc/sysdeps/linux/hppa/clone.S b/libc/sysdeps/linux/hppa/clone.S index f6c153b01..8356d9a74 100644 --- a/libc/sysdeps/linux/hppa/clone.S +++ b/libc/sysdeps/linux/hppa/clone.S @@ -1,5 +1,4 @@ -/* Copyright (C) 1996, 1997, 2000 Free Software Foundation, Inc. - This file is part of the GNU C Library. +/* Copyright (C) 1996-2018 Free Software Foundation, Inc. Contributed by David Huggins-Daines <dhd@debian.org>, 2000. Based on the Alpha version by Richard Henderson <rth@tamu.edu>, 1996. @@ -14,27 +13,35 @@ 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, see + License along with the GNU C Library. If not, see <http://www.gnu.org/licenses/>. */ /* 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/unistd.h> +#include <sysdep.h> #define _ERRNO_H 1 #include <bits/errno.h> -#include <sys/syscall.h> /* Non-thread code calls __clone with the following parameters: - int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg) - + int clone(int (*fn)(void *arg), + void *child_stack, + int flags, + void *arg) + NPTL Code will call __clone with the following parameters: - int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, - int *parent_tidptr, struct user_desc *newtls, int *child_pidptr) - + int clone(int (*fn)(void *arg), + void *child_stack, + int flags, + void *arg, + int *parent_tidptr, + struct user_desc *newtls, + int *child_pidptr) + The code should not mangle the extra input registers. Syscall expects: Input to __clone: - 4(r25) - function pointer (r26, arg0) + 4(r25) - function pointer (r26, arg0) 0(r25) - argument (r23, arg3) r26 - clone flags. (r24, arg2) r25+64 - user stack pointer. (r25, arg1) @@ -42,93 +49,114 @@ r23 - struct user_desc newtls pointer. (stack - 56) r22 - child tid pointer. (stack - 60) r20 - clone syscall number (constant) + + Return: + + On success the thread ID of the child process is returend in + the callers context. + On error return -1, and set errno to the value returned by + the syscall. */ -.text -.global __clone -.type __clone,%function -__clone: + .text +ENTRY(__clone) + /* Prologue */ + stwm %r4, 64(%sp) + .cfi_def_cfa_offset -64 + .cfi_offset 4, 0 + stw %sp, -4(%sp) +#ifdef __PIC__ + stw %r19, -32(%sp) + .cfi_offset 19, 32 +#endif /* Sanity check arguments. */ - ldi -EINVAL,%ret0 - comib,=,n 0,%arg0,.Lerror /* no NULL function pointers */ - comib,=,n 0,%arg1,.Lerror /* no NULL stack pointers */ + comib,=,n 0, %arg0, .LerrorSanity /* no NULL function pointers */ + comib,=,n 0, %arg1, .LerrorSanity /* no NULL stack pointers */ - /* Save the fn ptr and arg on the new stack. */ - stwm %r26,64(%r25) - stw %r23,-60(%r25) + /* Save the function pointer, arg, and flags on the new stack. */ + stwm %r26, 64(%r25) + stw %r23, -60(%r25) + stw %r24, -56(%r25) /* Clone arguments are (int flags, void * child_stack) */ - copy %r24,%r26 /* flags are first */ + copy %r24, %r26 /* flags are first */ /* User stack pointer is in the correct register already */ /* Load args from stack... */ - ldw -52(%sp), %r24 /* Load parent_tidptr */ - ldw -56(%sp), %r23 /* Load newtls */ - ldw -60(%sp), %r22 /* Load child_tidptr */ - - /* Create frame to get r3 free */ - copy %sp, %r21 - stwm %r3, 64(%sp) - stw %r21, -4(%sp) + ldw -116(%sp), %r24 /* Load parent_tidptr */ + ldw -120(%sp), %r23 /* Load newtls */ + ldw -124(%sp), %r22 /* Load child_tidptr */ /* Save the PIC register. */ #ifdef __PIC__ - copy %r19, %r3 /* parent */ + copy %r19, %r4 /* parent */ #endif /* Do the system call */ - ble 0x100(%sr2,%r0) - ldi __NR_clone,%r20 + ble 0x100(%sr2, %r0) + ldi __NR_clone, %r20 - ldi -4096,%r1 - comclr,>>= %r1,%ret0,%r0 /* Note: unsigned compare. */ + ldi -4096, %r1 + comclr,>>= %r1, %ret0, %r0 /* Note: unsigned compare. */ b,n .LerrorRest - comib,=,n 0,%ret0,thread_start + /* Restore the PIC register. */ +#ifdef __PIC__ + copy %r4, %r19 /* parent */ +#endif + + comib,=,n 0, %ret0, .LthreadStart /* Successful return from the parent - No need to restore the PIC register, + No need to restore the PIC register, since we return immediately. */ + ldw -84(%sp), %rp bv %r0(%rp) - ldwm -64(%sp), %r3 + ldwm -64(%sp), %r4 .LerrorRest: - /* Restore the PIC register on error */ -#ifdef __PIC__ - copy %r3, %r19 /* parent */ -#endif - /* Something bad happened -- no child created */ -.Lerror: - - /* Set errno, save ret0 so we return with that value. */ - copy %ret0, %r3 - b __syscall_error - sub %r0,%ret0,%arg0 - copy %r3, %ret0 - /* Return after setting errno, and restoring ret0 */ + bl __syscall_error, %rp + sub %r0, %ret0, %arg0 + ldw -84(%sp), %rp + /* Return after setting errno, ret0 is set to -1 by __syscall_error. */ bv %r0(%rp) - ldwm -64(%sp), %r3 + ldwm -64(%sp), %r4 -thread_start: +.LerrorSanity: + /* Sanity checks failed, return -1, and set errno to EINVAL. */ + bl __syscall_error, %rp + ldi EINVAL, %arg0 + ldw -84(%sp), %rp + bv %r0(%rp) + ldwm -64(%sp), %r4 +.LthreadStart: /* Load up the arguments. */ - ldw -60(%sr0, %sp),%arg0 - ldw -64(%sr0, %sp),%r22 + ldw -60(%sp), %arg0 + ldw -64(%sp), %r22 - /* $$dyncall fixes childs PIC register */ + /* $$dyncall fixes child's PIC register */ /* Call the user's function */ - bl $$dyncall,%r31 - copy %r31,%rp - - bl HIDDEN_JUMPTARGET(_exit),%rp - copy %ret0,%arg0 +#ifdef __PIC__ + copy %r19, %r4 +#endif + bl $$dyncall, %r31 + copy %r31, %rp +#ifdef __PIC__ + copy %r4, %r19 +#endif + copy %r28, %r26 + ble 0x100(%sr2, %r0) + ldi __NR_exit, %r20 - /* Die horribly. */ - iitlbp %r0,(%sr0,%r0) + /* We should not return from exit. + We do not restore r4, or the stack state. */ + iitlbp %r0, (%sr0, %r0) -.size clone,.-clone +PSEUDO_END(__clone) +libc_hidden_def (__clone) weak_alias (__clone, clone) |