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/****************************************************************************
* arch/arm/src/armv7/arm_addrenv_kstack.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Address Environment Interfaces
*
* Low-level interfaces used in binfmt/ to instantiate tasks with address
* environments. These interfaces all operate on type group_addrenv_t which
* is an abstract representation of a task group's address environment and
* must be defined in arch/arch.h if CONFIG_ARCH_ADDRENV is defined.
*
* up_addrenv_create - Create an address environment
* up_addrenv_destroy - Destroy an address environment.
* up_addrenv_vtext - Returns the virtual base address of the .text
* address environment
* up_addrenv_vdata - Returns the virtual base address of the .bss/.data
* address environment
* up_addrenv_heapsize - Returns the size of the initial heap allocation.
* up_addrenv_select - Instantiate an address environment
* up_addrenv_restore - Restore an address environment
* up_addrenv_clone - Copy an address environment from one location to
* another.
*
* Higher-level interfaces used by the tasking logic. These interfaces are
* used by the functions in sched/ and all operate on the thread which whose
* group been assigned an address environment by up_addrenv_clone().
*
* up_addrenv_attach - Clone the address environment assigned to one TCB
* to another. This operation is done when a pthread
* is created that share's the same group address
* environment.
* up_addrenv_detach - Release the thread's reference to an address
* environment when a task/thread exits.
*
* CONFIG_ARCH_STACK_DYNAMIC=y indicates that the user process stack resides
* in its own address space. This options is also *required* if
* CONFIG_BUILD_KERNEL and CONFIG_LIBC_EXECFUNCS are selected. Why?
* Because the caller's stack must be preserved in its own address space
* when we instantiate the environment of the new process in order to
* initialize it.
*
* NOTE: The naming of the CONFIG_ARCH_STACK_DYNAMIC selection implies that
* dynamic stack allocation is supported. Certainly this option must be set
* if dynamic stack allocation is supported by a platform. But the more
* general meaning of this configuration environment is simply that the
* stack has its own address space.
*
* If CONFIG_ARCH_STACK_DYNAMIC=y is selected then the platform specific
* code must export these additional interfaces:
*
* up_addrenv_ustackalloc - Create a stack address environment
* up_addrenv_ustackfree - Destroy a stack address environment.
* up_addrenv_vustack - Returns the virtual base address of the stack
* up_addrenv_ustackselect - Instantiate a stack address environment
*
* If CONFIG_ARCH_KERNEL_STACK is selected, then each user process will have
* two stacks: (1) a large (and possibly dynamic) user stack and (2) a
* smaller kernel stack. However, this option is *required* if both
* CONFIG_BUILD_KERNEL and CONFIG_LIBC_EXECFUNCS are selected. Why? Because
* when we instantiate and initialize the address environment of the new
* user process, we will temporarily lose the address environment of the old
* user process, including its stack contents. The kernel C logic will crash
* immediately with no valid stack in place.
*
* If CONFIG_ARCH_KERNEL_STACK=y is selected then the platform specific
* code must export these additional interfaces:
*
* up_addrenv_kstackalloc - Create a stack in the kernel address environment
* up_addrenv_kstackfree - Destroy the kernel stack.
* up_addrenv_vkstack - Return the base address of the kernel stack
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/sched.h>
#include <nuttx/kmalloc.h>
#include <nuttx/addrenv.h>
#include <nuttx/arch.h>
#include "addrenv.h"
#if defined(CONFIG_ARCH_ADDRENV) && defined(CONFIG_ARCH_KERNEL_STACK)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_addrenv_kstackalloc
*
* Description:
* This function is called when a new thread is created to allocate
* the new thread's kernel stack. This function may be called for certain
* terminating threads which have no kernel stack. It must be tolerant of
* that case.
*
* Input Parameters:
* tcb - The TCB of the thread that requires the kernel stack.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int up_addrenv_kstackalloc(FAR struct tcb_s *tcb)
{
bvdbg("tcb=%p stacksize=%u\n", tcb, ARCH_KERNEL_STACKSIZE);
DEBUGASSERT(tcb && tcb->xcp.kstack == 0);
/* Allocate the kernel stack */
tcb->xcp.kstack = (FAR uint32_t *)kmm_memalign(8, ARCH_KERNEL_STACKSIZE);
if (!tcb->xcp.kstack)
{
bdbg("ERROR: Failed to allocate the kernel stack\n");
return -ENOMEM;
}
return OK;
}
/****************************************************************************
* Name: up_addrenv_kstackfree
*
* Description:
* This function is called when any thread exits. This function frees
* the kernel stack.
*
* Input Parameters:
* tcb - The TCB of the thread that no longer requires the kernel stack.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int up_addrenv_kstackfree(FAR struct tcb_s *tcb)
{
bvdbg("tcb=%p\n", tcb);
DEBUGASSERT(tcb);
/* Does the exiting thread have a kernel stack? */
if (tcb->xcp.kstack)
{
/* Yes.. Free the kernel stack */
kmm_free(tcb->xcp.kstack);
tcb->xcp.kstack = NULL;
}
return OK;
}
#endif /* CONFIG_ARCH_ADDRENV && CONFIG_ARCH_KERNEL_STACK */
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