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Diffstat (limited to 'nuttx/arch/arm/src/common/up_vfork.c')
| -rw-r--r-- | nuttx/arch/arm/src/common/up_vfork.c | 233 |
1 files changed, 0 insertions, 233 deletions
diff --git a/nuttx/arch/arm/src/common/up_vfork.c b/nuttx/arch/arm/src/common/up_vfork.c deleted file mode 100644 index 3b653e317..000000000 --- a/nuttx/arch/arm/src/common/up_vfork.c +++ /dev/null @@ -1,233 +0,0 @@ -/**************************************************************************** - * arch/arm/src/common/up_vfork.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 <stdint.h> -#include <string.h> -#include <assert.h> -#include <errno.h> -#include <debug.h> - -#include <nuttx/sched.h> -#include <nuttx/arch.h> -#include <arch/irq.h> - -#include "up_vfork.h" -#include "os_internal.h" - -/**************************************************************************** - * Pre-processor Definitions - ****************************************************************************/ - -/* ARM requires at least a 4-byte stack alignment. For use with EABI and - * floating point, the stack must be aligned to 8-byte addresses. - */ - -#ifndef CONFIG_STACK_ALIGNMENT - -/* The symbol __ARM_EABI__ is defined by GCC if EABI is being used. If you - * are not using GCC, make sure that CONFIG_STACK_ALIGNMENT is set correctly! - */ - -# ifdef __ARM_EABI__ -# define CONFIG_STACK_ALIGNMENT 8 -# else -# define CONFIG_STACK_ALIGNMENT 4 -# endif -#endif - -/**************************************************************************** - * Private Functions - ****************************************************************************/ - -/**************************************************************************** - * Public Functions - ****************************************************************************/ - -/**************************************************************************** - * Name: up_vfork - * - * Description: - * The vfork() function has the same effect as fork(), except that the - * behavior is undefined if the process created by vfork() either modifies - * any data other than a variable of type pid_t used to store the return - * value from vfork(), or returns from the function in which vfork() was - * called, or calls any other function before successfully calling _exit() - * or one of the exec family of functions. - * - * The overall sequence is: - * - * 1) User code calls vfork(). vfork() collects context information and - * transfers control up up_vfork(). - * 2) up_vfork()and calls task_vforksetup(). - * 3) task_vforksetup() allocates and configures the child task's TCB. This - * consists of: - * - Allocation of the child task's TCB. - * - Initialization of file descriptors and streams - * - Configuration of environment variables - * - Setup the intput parameters for the task. - * - Initialization of the TCB (including call to up_initial_state() - * 4) up_vfork() provides any additional operating context. up_vfork must: - * - Allocate and initialize the stack - * - Initialize special values in any CPU registers that were not - * already configured by up_initial_state() - * 5) up_vfork() then calls task_vforkstart() - * 6) task_vforkstart() then executes the child thread. - * - * task_vforkabort() may be called if an error occurs between steps 3 and 6. - * - * Input Paremeters: - * context - Caller context information saved by vfork() - * - * Return: - * Upon successful completion, vfork() returns 0 to the child process and - * returns the process ID of the child process to the parent process. - * Otherwise, -1 is returned to the parent, no child process is created, - * and errno is set to indicate the error. - * - ****************************************************************************/ - -pid_t up_vfork(const struct vfork_s *context) -{ - _TCB *parent = (FAR _TCB *)g_readytorun.head; - _TCB *child; - size_t stacksize; - uint32_t newsp; - uint32_t newfp; - uint32_t stackutil; - int ret; - - svdbg("r4:%08x r5:%08x r6:%08x r7:%08x\n", - context->r4, context->r5, context->r6, context->r7); - svdbg("r8:%08x r9:%08x r10:%08x\n", - context->r8, context->r9, context->r10); - svdbg("fp:%08x sp:%08x lr:%08x\n", - context->fp, context->sp, context->lr); - - /* Allocate and initialize a TCB for the child task. */ - - child = task_vforksetup((start_t)(context->lr & ~1)); - if (!child) - { - sdbg("task_vforksetup failed\n"); - return (pid_t)ERROR; - } - - svdbg("Parent=%p Child=%p\n", parent, child); - - /* Get the size of the parent task's stack. Due to alignment operations, - * the adjusted stack size may be smaller than the stack size originally - * requrested. - */ - - stacksize = parent->adj_stack_size + CONFIG_STACK_ALIGNMENT - 1; - - /* Allocate the stack for the TCB */ - - ret = up_create_stack(child, stacksize); - if (ret != OK) - { - sdbg("up_create_stack failed: %d\n", ret); - task_vforkabort(child, -ret); - return (pid_t)ERROR; - } - - /* How much of the parent's stack was utilized? The ARM uses - * a push-down stack so that the current stack pointer should - * be lower than the initial, adjusted stack pointer. The - * stack usage should be the difference between those two. - */ - - DEBUGASSERT((uint32_t)parent->adj_stack_ptr > context->sp); - stackutil = (uint32_t)parent->adj_stack_ptr - context->sp; - - svdbg("stacksize:%d stackutil:%d\n", stacksize, stackutil); - - /* Make some feeble effort to perserve the stack contents. This is - * feeble because the stack surely contains invalid pointers and other - * content that will not work in the child context. However, if the - * user follows all of the caveats of vfor() usage, even this feeble - * effort is overkill. - */ - - newsp = (uint32_t)child->adj_stack_ptr - stackutil; - memcpy((void *)newsp, (const void *)context->sp, stackutil); - - /* Was there a frame pointer in place before? */ - - if (context->fp <= (uint32_t)parent->adj_stack_ptr && - context->fp >= (uint32_t)parent->adj_stack_ptr - stacksize) - { - uint32_t frameutil = (uint32_t)parent->adj_stack_ptr - context->fp; - newfp = (uint32_t)child->adj_stack_ptr - frameutil; - } - else - { - newfp = context->fp; - } - - svdbg("Old stack base:%08x SP:%08x FP:%08x\n", - parent->adj_stack_ptr, context->sp, context->fp); - svdbg("New stack base:%08x SP:%08x FP:%08x\n", - child->adj_stack_ptr, newsp, newfp); - - /* Update the stack pointer, frame pointer, and volatile registers. When - * the child TCB was initialized, all of the values were set to zero. - * up_initial_state() altered a few values, but the return value in R0 - * should be cleared to zero, providing the indication to the newly started - * child thread. - */ - - child->xcp.regs[REG_R4] = context->r4; /* Volatile register r4 */ - child->xcp.regs[REG_R5] = context->r5; /* Volatile register r5 */ - child->xcp.regs[REG_R6] = context->r6; /* Volatile register r6 */ - child->xcp.regs[REG_R7] = context->r7; /* Volatile register r7 */ - child->xcp.regs[REG_R8] = context->r8; /* Volatile register r8 */ - child->xcp.regs[REG_R9] = context->r9; /* Volatile register r9 */ - child->xcp.regs[REG_R10] = context->r10; /* Volatile register r10 */ - child->xcp.regs[REG_FP] = newfp; /* Frame pointer */ - child->xcp.regs[REG_SP] = newsp; /* Stack pointer */ - - /* And, finally, start the child task. On a failure, task_vforkstart() - * will discard the TCB by calling task_vforkabort(). - */ - - return task_vforkstart(child); -} |