diff options
Diffstat (limited to 'nuttx/arch/x86/src/i486/up_stackframe.c')
-rw-r--r-- | nuttx/arch/x86/src/i486/up_stackframe.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/nuttx/arch/x86/src/i486/up_stackframe.c b/nuttx/arch/x86/src/i486/up_stackframe.c new file mode 100644 index 000000000..ea4edc07a --- /dev/null +++ b/nuttx/arch/x86/src/i486/up_stackframe.c @@ -0,0 +1,134 @@ +/**************************************************************************** + * arch/x86/src/i486/up_stackframe.c + * + * Copyright (C) 2013 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. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <sys/types.h> +#include <stdint.h> +#include <sched.h> +#include <debug.h> + +#include <nuttx/arch.h> + +#include "up_internal.h" + +/**************************************************************************** + * Pre-processor Macros + ****************************************************************************/ + +/* The initial stack point is aligned at word (4 byte) boundaries. If + * necessary frame_size must be rounded up to the next boundary to retain + * this alignment. + */ + +#define STACK_ALIGNMENT 4 + +/* Stack alignment macros */ + +#define STACK_ALIGN_MASK (STACK_ALIGNMENT-1) +#define STACK_ALIGN_DOWN(a) ((a) & ~STACK_ALIGN_MASK) +#define STACK_ALIGN_UP(a) (((a) + STACK_ALIGN_MASK) & ~STACK_ALIGN_MASK) + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Global Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: up_stack_frame + * + * Description: + * Allocate a stack frame in the TCB's stack to hold thread-specific data. + * This function may be called anytime after up_create_stack() or + * up_use_stack() have been called but before the task has been started. + * + * Thread data may be kept in the stack (instead of in the TCB) if it is + * accessed by the user code directory. This includes such things as + * argv[]. The stack memory is guaranteed to be in the same protection + * domain as the thread. + * + * The following TCB fields will be re-initialized: + * + * - adj_stack_size: Stack size after removal of the stack frame from + * the stack + * - adj_stack_ptr: Adjusted initial stack pointer after the frame has + * been removed from the stack. This will still be the initial value + * of the stack pointer when the task is started. + * + * Inputs: + * - tcb: The TCB of new task + * - frame_size: The size of the stack frame to allocate. + * + * Returned Value: + * - A pointer to bottom of the allocated stack frame. NULL will be + * returned on any failures. The alignment of the returned value is + * the same as the alignment of the stack itself. + * + ****************************************************************************/ + +FAR void *up_stack_frame(FAR struct tcb_s *tcb, size_t frame_size) +{ + uintptr_t topaddr; + + /* Align the frame_size */ + + frame_size = STACK_ALIGN_UP(frame_size); + + /* Is there already a stack allocated? Is it big enough? */ + + if (!tcb->stack_alloc_ptr || tcb->adj_stack_size <= frame_size) + { + return NULL; + } + + /* Save the adjusted stack values in the struct tcb_s */ + + topaddr = (uintptr_t)tcb->adj_stack_ptr - frame_size; + tcb->adj_stack_ptr = (FAR void *)topaddr; + tcb->adj_stack_size -= frame_size; + + return (FAR void *)(topaddr + sizeof(uint32_t)); +} |