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diff --git a/nuttx/Documentation/NuttxPortingGuide.html b/nuttx/Documentation/NuttxPortingGuide.html index eb5a67cc1..9ebccab1b 100644 --- a/nuttx/Documentation/NuttxPortingGuide.html +++ b/nuttx/Documentation/NuttxPortingGuide.html @@ -12,7 +12,7 @@ <h1><big><font color="#3c34ec"> <i>NuttX RTOS Porting Guide</i> </font></big></h1> - <p>Last Updated: September 10, 2014</p> + <p>Last Updated: September 13, 2014</p> </td> </tr> </table> @@ -115,7 +115,11 @@ <a href="#up_addrenv_restore">4.4.7 <code>up_addrenv_restore()</code></a></br> <a href="#up_addrenv_clone">4.4.8 <code>up_addrenv_clone()</code></a></br> <a href="#up_addrenv_attach">4.4.9 <code>up_addrenv_attach()</code></a></br> - <a href="#up_addrenv_detach">4.4.10 <code>up_addrenv_detach()</code></a> + <a href="#up_addrenv_detach">4.4.10 <code>up_addrenv_detach()</code></a></br> + <a href="#up_addrenv_stackalloc">4.4.11 <code>up_addrenv_stackalloc()</code></a></br> + <a href="#up_addrenv_stackfree">4.4.12 <code>up_addrenv_stackfree()</code></a></br> + <a href="#up_addrenv_vstack">4.4.13 <code>up_addrenv_vstack()</code></a></br> + <a href="#up_addrenv_stackselect">4.4.14 <code>up_addrenv_stackselect()</code></a> </ul> <a href="#exports">4.5 APIs Exported by NuttX to Architecture-Specific Logic</a> <ul> @@ -2963,6 +2967,37 @@ VxWorks provides the following comparable interface: </li> </ul> </li> + <li> + <p> + <b>Dynamic Stack Support</b>. + <code>CONFIG_ARCH_STACK_DYNAMIC=y</code> indicates that the user process stack resides in its own address space. + This options is also <i>required</i> if <code> CONFIG_BUILD_KERNEL</code> and <code>CONFIG_LIBC_EXECFUNCS</code> 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. + </p> + <p> + <b>NOTE:</b> The naming of the <code>CONFIG_ARCH_STACK_DYNAMIC</code> 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. + </p> + <p> + If <code>CONFIG_ARCH_STACK_DYNAMIC=y</code> is selected then the platform specific code must export these additional interfaces: + </p> + <ul> + <li> + <a href="#up_addrenv_stackalloc">4.4.11 <code>up_addrenv_stackalloc()</code></a>: + Create a stack address environment + <li> + <a href="#up_addrenv_stackfree">4.4.12 <code>up_addrenv_stackfree()</code></a>: + Destroy a stack address environment. + <li> + <a href="#up_addrenv_vstack">4.4.13 <code>up_addrenv_vstack()</code></a>: + Returns the virtual base address of the stack + <li> + <a href="#up_addrenv_stackselect">4.4.14 <code>up_addrenv_stackselect()</code></a>: + Instantiate a stack address environment + </ul> + </li> </ol> <h3><a name="up_addrenv_create">4.4.1 <code>up_addrenv_create()</code></a></h3> @@ -3173,6 +3208,92 @@ VxWorks provides the following comparable interface: Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure. </ul> +<h3><a name="up_addrenv_stackalloc">4.4.11 <code>up_addrenv_stackalloc()</code></a></h3> +<p><b>Function Prototype</b>:<p> +<ul> + <code>int up_addrenv_stackalloc(FAR struct tcb_s *tcb, size_t stacksize);</code> +</ul> +<p><b>Description</b>:</p> +<ul> +<p> + This function is called when a new thread is created in order to instantiate an address environment for the new thread's stack. + <code>up_addrenv_stackalloc()</code> is essentially the allocator of the physical memory for the new task's stack. +</p> +</ul> +<p><b>Input Parameters</b>:</p> +<ul> + <li><code>tcb</code>: The TCB of the thread that requires the stack address environment.</li> + <li><code>stacksize</code>: The size (in bytes) of the initial stack address environment needed by the task. This region may be read/write only.</li> +</ul> +<p><b>Returned Value</b>:</p> +<ul> + Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure. +</ul> + +<h3><a name="up_addrenv_up_addrenv_stackfreeattach">4.4.12 <code>up_addrenv_stackfree()</code></a></h3> +<p><b>Function Prototype</b>:<p> +<ul> + <code>int up_addrenv_stackfree(FAR struct tcb_s *tcb);</code> +</ul> +<p><b>Description</b>:</p> +<ul> + <p> + This function is called when any thread exits. + This function then destroys the defunct address environment for the thread's stack, releasing the underlying physical memory. + </p> +</ul> +<p><b>Input Parameters</b>:</p> +<ul> + <li><code>tcb</code>: The TCB of the thread that no longer requires the stack address environment.</li> +</ul> +<p><b>Returned Value</b>:</p> +<ul> + Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure. +</ul> + +<h3><a name="up_addrenv_vstack">4.4.13 <code>up_addrenv_vstack()</code></a></h3> +<p><b>Function Prototype</b>:<p> +<ul> + <code>int up_addrenv_vstack(FAR const struct tcb_s *tcb, FAR void **vstack);</code> +</ul> +<p><b>Description</b>:</p> +<ul> + <p> + Return the virtual address associated with the newly create stack address environment. + </p> +</ul> +<p><b>Input Parameters</b>:</p> +<ul> + <li><code>tcb</code>:The TCB of the thread with the stack address environment of interest. </li> + <li><code>vstack</code>: The location to return the stack virtual base address.</li> +</ul> +<p><b>Returned Value</b>:</p> +<ul> + Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure. +</ul> + +<h3><a name="up_addrenv_stackselect">4.4.14 <code>up_addrenv_stackselect()</code></a></h3> +<p><b>Function Prototype</b>:<p> +<ul> + <code>int up_addrenv_stackselect(FAR const struct tcb_s *tcb);</code> +</ul> +<p><b>Description</b>:</p> +<ul> + <P> + After an address environment has been established for a task's stack (via <code>up_addrenv_stackalloc()</code>. + This function may be called to instantiate that address environment in the virtual address space. + This is a necessary step before each context switch to the newly created thread (including the initial thread startup). + </p> +</ul> +<p><b>Input Parameters</b>:</p> +<ul> + <li><code>tcb</code>: The TCB of the thread with the stack address environment to be instantiated.</li> +</ul> +<p><b>Returned Value</b>:</p> +<ul> + Zero (<code>OK</code>) on success; a negated <code>errno</code> value on failure. +</ul> + <h2><a name="exports">4.5 APIs Exported by NuttX to Architecture-Specific Logic</a></h2> <p> These are standard interfaces that are exported by the OS |