glibc/sysdeps/unix/sysv/linux/arm/eabi/nptl/sysdep-cancel.h

/* Copyright (C) 2003, 2004, 2005 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
   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.  */

#include <sysdep.h>
#include <tls.h>
#ifndef __ASSEMBLER__
# include <nptl/pthreadP.h>
#endif

#if !defined NOT_IN_libc || defined IS_IN_libpthread || defined IS_IN_librt

/* NOTE: We do mark syscalls with unwind annotations, for the benefit of
   cancellation; but they're really only accurate at the point of the
   syscall.  The ARM unwind directives are not rich enough without adding
   a custom personality function.  */

# undef PSEUDO
# define PSEUDO(name, syscall_name, args)				\
  .section ".text";							\
    PSEUDO_PROLOGUE;							\
  .type __##syscall_name##_nocancel,%function;				\
  .globl __##syscall_name##_nocancel;					\
  __##syscall_name##_nocancel:						\
    DO_CALL (syscall_name, args);					\
    PSEUDO_RET;								\
  .size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel;	\
  ENTRY (name);								\
    SINGLE_THREAD_P;							\
    DOARGS_##args;							\
    bne .Lpseudo_cancel;						\
    DO_CALL (syscall_name, 0);						\
    UNDOARGS_##args;							\
    cmn r0, $4096;							\
    PSEUDO_RET;								\
  .Lpseudo_cancel:							\
    .fnstart;								\
    DOCARGS_##args;	/* save syscall args etc. around CENABLE.  */	\
    CENABLE;								\
    mov ip, r0;		/* put mask in safe place.  */			\
    UNDOCARGS_##args;	/* restore syscall args.  */			\
    ldr r7, =SYS_ify (syscall_name);					\
    swi 0x0;		/* do the call.  */				\
    .fnend;		/* Past here we can't easily unwind.  */	\
    mov r7, r0;		/* save syscall return value.  */		\
    mov r0, ip;		/* get mask back.  */				\
    CDISABLE;								\
    mov r0, r7;		/* retrieve return value.  */			\
    RESTORE_LR_##args;							\
    UNDOARGS_##args;							\
    cmn r0, $4096;

/* DOARGS pushes four bytes on the stack for five arguments, and nothing
   otherwise.  In order to preserve doubleword alignment, sometimes we must
   save an extra register.  */

# define RESTART_UNWIND .fnend; .fnstart; .save {r7, lr}

# define DOCARGS_0	stmfd sp!, {r7, lr}; .save {r7, lr}
# define UNDOCARGS_0
# define RESTORE_LR_0	ldmfd sp!, {r7, lr};

# define DOCARGS_1	stmfd sp!, {r0, r1, r7, lr}; .save {r7, lr}; .pad #8
# define UNDOCARGS_1	ldr r0, [sp], #8; RESTART_UNWIND
# define RESTORE_LR_1	RESTORE_LR_0

# define DOCARGS_2	stmfd sp!, {r0, r1, r7, lr}; .save {r7, lr}; .pad #8
# define UNDOCARGS_2	ldmfd sp!, {r0, r1}; RESTART_UNWIND
# define RESTORE_LR_2	RESTORE_LR_0

# define DOCARGS_3	stmfd sp!, {r0, r1, r2, r3, r7, lr}; .save {r7, lr}; .pad #16
# define UNDOCARGS_3	ldmfd sp!, {r0, r1, r2, r3}; RESTART_UNWIND
# define RESTORE_LR_3	RESTORE_LR_0

# define DOCARGS_4	stmfd sp!, {r0, r1, r2, r3, r7, lr}; .save {r7, lr}; .pad #16
# define UNDOCARGS_4	ldmfd sp!, {r0, r1, r2, r3}; RESTART_UNWIND
# define RESTORE_LR_4	RESTORE_LR_0

# define DOCARGS_5	.save {r4}; stmfd sp!, {r0, r1, r2, r3, r4, r7, lr}; .save {r7, lr}; .pad #20
# define UNDOCARGS_5	ldmfd sp!, {r0, r1, r2, r3}; .fnend; .fnstart; .save {r4}; .save {r7, lr}; .pad #4
# define RESTORE_LR_5	ldmfd sp!, {r4, r7, lr}

# ifdef IS_IN_libpthread
#  define CENABLE	bl PLTJMP(__pthread_enable_asynccancel)
#  define CDISABLE	bl PLTJMP(__pthread_disable_asynccancel)
#  define __local_multiple_threads __pthread_multiple_threads
# elif !defined NOT_IN_libc
#  define CENABLE	bl PLTJMP(__libc_enable_asynccancel)
#  define CDISABLE	bl PLTJMP(__libc_disable_asynccancel)
#  define __local_multiple_threads __libc_multiple_threads
# elif defined IS_IN_librt
#  define CENABLE	bl PLTJMP(__librt_enable_asynccancel)
#  define CDISABLE	bl PLTJMP(__librt_disable_asynccancel)
# else
#  error Unsupported library
# endif

# if defined IS_IN_libpthread || !defined NOT_IN_libc
#  ifndef __ASSEMBLER__
extern int __local_multiple_threads attribute_hidden;
#   define SINGLE_THREAD_P __builtin_expect (__local_multiple_threads == 0, 1)
#  else
#   define SINGLE_THREAD_P						\
  ldr ip, 1b;								\
2:									\
  ldr ip, [pc, ip];							\
  teq ip, #0;
#   define PSEUDO_PROLOGUE						\
  1:  .word __local_multiple_threads - 2f - 8;
#  endif
# else
/*  There is no __local_multiple_threads for librt, so use the TCB.  */
#  ifndef __ASSEMBLER__
#   define SINGLE_THREAD_P						\
  __builtin_expect (THREAD_GETMEM (THREAD_SELF,				\
				   header.multiple_threads) == 0, 1)
#  else
#   define PSEUDO_PROLOGUE
#   define SINGLE_THREAD_P						\
  stmfd	sp!, {r0, lr};							\
  bl	__aeabi_read_tp;						\
  ldr	ip, [r0, #MULTIPLE_THREADS_OFFSET];				\
  ldmfd	sp!, {r0, lr};							\
  teq	ip, #0
#   define SINGLE_THREAD_P_PIC(x) SINGLE_THREAD_P
#  endif
# endif

#elif !defined __ASSEMBLER__

/* For rtld, et cetera.  */
# define SINGLE_THREAD_P 1
# define NO_CANCELLATION 1

#endif