| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- |
| -- -- |
| -- S Y S T E M . S T A C K _ C H E C K I N G . O P E R A T I O N S -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1999-2021, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNARL is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNARL was developed by the GNARL team at Florida State University. -- |
| -- Extensive contributions were provided by Ada Core Technologies, Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package provides a implementation of stack checking operations using |
| -- comparison with stack base and limit. |
| |
| pragma Restrictions (No_Elaboration_Code); |
| -- We want to guarantee the absence of elaboration code because the binder |
| -- does not handle references to this package. |
| |
| with System.Storage_Elements; |
| |
| package System.Stack_Checking.Operations is |
| pragma Preelaborate; |
| |
| procedure Update_Stack_Cache (Stack : Stack_Access); |
| -- Set the stack cache for the current task. Note that this is only for |
| -- optimization purposes, nothing can be assumed about the contents of the |
| -- cache at any time, see Set_Stack_Info. |
| -- |
| -- The stack cache should contain the bounds of the current task. But |
| -- because the RTS is not aware of task switches, the stack cache may be |
| -- incorrect. So when the stack pointer is not within the bounds of the |
| -- stack cache, Stack_Check first update the cache (which is a costly |
| -- operation hence the need of a cache). |
| |
| procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access); |
| -- Invalidate cache entries for the task T that owns Any_Stack. This causes |
| -- the Set_Stack_Info function to be called during the next stack check |
| -- done by T. This can be used to interrupt task T asynchronously. |
| -- Stack_Check should be called in loops for this to work reliably. |
| |
| function Stack_Check (Stack_Address : System.Address) return Stack_Access; |
| -- This version of Stack_Check should not be inlined |
| |
| procedure Notify_Stack_Attributes |
| (Initial_SP : System.Address; |
| Size : System.Storage_Elements.Storage_Offset); |
| -- Register Initial_SP as the initial stack pointer value for the current |
| -- task when it starts and Size as the associated stack area size. This |
| -- should be called once, after the soft-links have been initialized and |
| -- prior to the first "Stack_Check" call. |
| |
| private |
| Cache : aliased Stack_Access := Null_Stack; |
| |
| pragma Export (C, Cache, "_gnat_stack_cache"); |
| pragma Export (C, Stack_Check, "_gnat_stack_check"); |
| |
| end System.Stack_Checking.Operations; |
