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Diffstat (limited to 'hurd/hurd/threadvar.h')
| -rw-r--r-- | hurd/hurd/threadvar.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/hurd/hurd/threadvar.h b/hurd/hurd/threadvar.h new file mode 100644 index 0000000000..eab133a2f6 --- /dev/null +++ b/hurd/hurd/threadvar.h @@ -0,0 +1,107 @@ +/* Internal per-thread variables for the Hurd. +Copyright (C) 1994 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 Library General Public License as +published by the Free Software Foundation; either version 2 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 +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#ifndef _HURD_THREADVAR_H +#define _HURD_THREADVAR_H + +/* The per-thread variables are found by ANDing this mask + with the value of the stack pointer and then adding this offset. + + In the multi-threaded case, cthreads initialization sets + __hurd_threadvar_stack_mask to ~(cthread_stack_size - 1), a mask which + finds the base of the fixed-size cthreads stack; and + __hurd_threadvar_stack_offset to a small offset that skips the data + cthreads itself maintains at the base of each thread's stack. + + In the single-threaded case, __hurd_threadvar_stack_mask is zero, so the + stack pointer is ignored; and __hurd_threadvar_stack_offset gives the + address of a small allocated region which contains the variables for the + single thread. */ + +extern unsigned long int __hurd_threadvar_stack_mask; +extern unsigned long int __hurd_threadvar_stack_offset; + +/* A special case must always be made for the signal thread. Even when there + is only one user thread and an allocated region can be used for the user + thread's variables, the signal thread needs to have its own location for + per-thread variables. The variables __hurd_sigthread_stack_base and + __hurd_sigthread_stack_end define the bounds of the stack used by the + signal thread, so that thread can always be specifically identified. */ + +extern unsigned long int __hurd_sigthread_stack_base; +extern unsigned long int __hurd_sigthread_stack_end; +extern unsigned long int *__hurd_sigthread_variables; + + +/* At the location described by the two variables above, + there are __hurd_threadvar_max `unsigned long int's of per-thread data. */ +extern unsigned int __hurd_threadvar_max; + +/* These values are the indices for the standard per-thread variables. */ +enum __hurd_threadvar_index + { + _HURD_THREADVAR_MIG_REPLY, /* Reply port for MiG user stub functions. */ + _HURD_THREADVAR_ERRNO, /* `errno' value for this thread. */ + _HURD_THREADVAR_SIGSTATE, /* This thread's `struct hurd_sigstate'. */ + _HURD_THREADVAR_DYNAMIC_USER, /* Dynamically-assigned user variables. */ + _HURD_THREADVAR_MAX /* Default value for __hurd_threadvar_max. */ + }; + + +#ifndef _EXTERN_INLINE +#define _EXTERN_INLINE extern __inline +#endif + +/* Return the location of the value for the per-thread variable with index + INDEX used by the thread whose stack pointer is SP. */ + +_EXTERN_INLINE unsigned long int * +__hurd_threadvar_location_from_sp (enum __hurd_threadvar_index __index, + void *__sp) +{ + unsigned long int __stack = (unsigned long int) __sp; + return &((__stack >= __hurd_sigthread_stack_base && + __stack < __hurd_sigthread_stack_end) + ? __hurd_sigthread_variables + : (unsigned long int *) ((__stack & __hurd_threadvar_stack_mask) + + __hurd_threadvar_stack_offset))[__index]; +} + +#include <machine-sp.h> /* Define __thread_stack_pointer. */ + +/* Return the location of the current thread's value for the + per-thread variable with index INDEX. */ + +_EXTERN_INLINE unsigned long int * +__hurd_threadvar_location (enum __hurd_threadvar_index __index) +{ + return __hurd_threadvar_location_from_sp (__index, + __thread_stack_pointer ()); +} + +/* Return the current thread's location for `errno'. + The syntax of this function allows redeclarations like `int errno'. */ +_EXTERN_INLINE int * +__hurd_errno_location (void) +{ + return (int *) __hurd_threadvar_location (_HURD_THREADVAR_ERRNO); +} + + +#endif /* hurd/threadvar.h */ |