mirror of
https://github.com/espressif/esp-idf.git
synced 2025-08-05 05:34:32 +02:00
freertos: Refactor riscv port stack initialization code
This commit refactors the pxPortInitialiseStack() function of the riscv
FreeRTOS ports (both IDF and SMP FreeRTOS).
- Each stack area is now separated into their own functions
- Each function will individually
- Push the stack pointer to allocate the stack area
- Initiaze the allocated stack area
- Each stack area's size and usage is now clearly documented in code
This commit is contained in:
Darian Leung
@@ -538,78 +538,161 @@ __attribute__((naked)) static void prvTaskExitError(void)
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_prvTaskExitError();
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}
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StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
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{
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extern uint32_t __global_pointer$;
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uint8_t *task_thread_local_start;
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uint8_t *threadptr;
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extern char _thread_local_start, _thread_local_end, _flash_rodata_start;
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/* Byte pointer, so that subsequent calculations don't depend on sizeof(StackType_t). */
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uint8_t *sp = (uint8_t *) pxTopOfStack;
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/* Set up TLS area.
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* The following diagram illustrates the layout of link-time and run-time
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* TLS sections.
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/**
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* @brief Align stack pointer in a downward growing stack
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*
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* +-------------+
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* |Section: | Linker symbols:
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* |.flash.rodata| ---------------
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* 0x0+-------------+ <-- _flash_rodata_start
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* ^ | |
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* | | Other data |
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* | | ... |
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* | +-------------+ <-- _thread_local_start
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* | |.tbss | ^
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* v | | |
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* 0xNNNN|int example; | | (thread_local_size)
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* |.tdata | v
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* +-------------+ <-- _thread_local_end
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* | Other data |
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* | ... |
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* | |
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* +-------------+
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*
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* Local variables of
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* pxPortInitialiseStack
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* -----------------------
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* +-------------+ <-- pxTopOfStack
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* |.tdata (*) | ^
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* ^ |int example; | |(thread_local_size
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* | | | |
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* | |.tbss (*) | v
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* | +-------------+ <-- task_thread_local_start
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* 0xNNNN | | | ^
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* | | | |
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* | | | |_thread_local_start - _rodata_start
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* | | | |
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* | | | v
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* v +-------------+ <-- threadptr
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*
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* (*) The stack grows downward!
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* This macro is used to round a stack pointer downwards to the nearest n-byte boundary, where n is a power of 2.
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* This macro is generally used when allocating aligned areas on a downward growing stack.
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*/
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#define STACKPTR_ALIGN_DOWN(n, ptr) ((ptr) & (~((n)-1)))
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uint32_t thread_local_sz = (uint32_t) (&_thread_local_end - &_thread_local_start);
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thread_local_sz = ALIGNUP(0x10, thread_local_sz);
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sp -= thread_local_sz;
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task_thread_local_start = sp;
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memcpy(task_thread_local_start, &_thread_local_start, thread_local_sz);
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threadptr = task_thread_local_start - (&_thread_local_start - &_flash_rodata_start);
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/**
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* @brief Allocate and initialize GCC TLS area
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*
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* This function allocates and initializes the area on the stack used to store GCC TLS (Thread Local Storage) variables.
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* - The area's size is derived from the TLS section's linker variables, and rounded up to a multiple of 16 bytes
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* - The allocated area is aligned to a 16-byte aligned address
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* - The TLS variables in the area are then initialized
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*
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* Each task access the TLS variables using the THREADPTR register plus an offset to obtain the address of the variable.
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* The value for the THREADPTR register is also calculated by this function, and that value should be use to initialize
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* the THREADPTR register.
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*
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* @param[in] uxStackPointer Current stack pointer address
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* @param[out] ret_threadptr_reg_init Calculated THREADPTR register initialization value
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* @return Stack pointer that points to the TLS area
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*/
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FORCE_INLINE_ATTR UBaseType_t uxInitialiseStackTLS(UBaseType_t uxStackPointer, uint32_t *ret_threadptr_reg_init)
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{
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/*
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TLS layout at link-time, where 0xNNN is the offset that the linker calculates to a particular TLS variable.
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/* Simulate the stack frame as it would be created by a context switch interrupt. */
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sp -= RV_STK_FRMSZ;
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RvExcFrame *frame = (RvExcFrame *)sp;
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memset(frame, 0, sizeof(*frame));
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/* Shifting RA into prvTaskExitError is necessary to make GDB backtrace ending inside that function.
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Otherwise backtrace will end in the function laying just before prvTaskExitError in address space. */
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frame->ra = (UBaseType_t)prvTaskExitError + 4/*size of the nop insruction at the beginning of prvTaskExitError*/;
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LOW ADDRESS
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|---------------------------| Linker Symbols
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| Section | --------------
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| .flash.rodata |
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0x0|---------------------------| <- _flash_rodata_start
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^ | Other Data |
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| |---------------------------| <- _thread_local_start
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| | .tbss | ^
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V | | |
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0xNNN | int example; | | tls_area_size
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| | |
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| .tdata | V
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|---------------------------| <- _thread_local_end
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| Other data |
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| ... |
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|---------------------------|
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HIGH ADDRESS
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*/
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// Calculate TLS area size and round up to multiple of 16 bytes.
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extern char _thread_local_start, _thread_local_end, _flash_rodata_start;
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const uint32_t tls_area_size = ALIGNUP(16, (uint32_t)&_thread_local_end - (uint32_t)&_thread_local_start);
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// TODO: check that TLS area fits the stack
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// Allocate space for the TLS area on the stack. The area must be aligned to 16-bytes
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uxStackPointer = STACKPTR_ALIGN_DOWN(16, uxStackPointer - (UBaseType_t)tls_area_size);
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// Initialize the TLS area with the initialization values of each TLS variable
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memcpy((void *)uxStackPointer, &_thread_local_start, tls_area_size);
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/*
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Calculate the THREADPTR register's initialization value based on the link-time offset and the TLS area allocated on
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the stack.
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HIGH ADDRESS
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|---------------------------|
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| .tdata (*) |
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^ | int example; |
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| | |
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| | .tbss (*) |
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| |---------------------------| <- uxStackPointer (start of TLS area)
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0xNNN | | | ^
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| | | |
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| ... | _thread_local_start - _rodata_start
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| | | V
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V | | <- threadptr register's value
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LOW ADDRESS
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*/
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*ret_threadptr_reg_init = (uint32_t)uxStackPointer - ((uint32_t)&_thread_local_start - (uint32_t)&_flash_rodata_start);
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return uxStackPointer;
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}
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/**
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* @brief Initialize the task's starting interrupt stack frame
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*
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* This function initializes the task's starting interrupt stack frame. The dispatcher will use this stack frame in a
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* context restore routine. Therefore, the starting stack frame must be initialized as if the task was interrupted right
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* before its first instruction is called.
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*
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* - The stack frame is allocated to a 16-byte aligned address
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*
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* @param[in] uxStackPointer Current stack pointer address
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* @param[in] pxCode Task function
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* @param[in] pvParameters Task function's parameter
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* @param[in] threadptr_reg_init THREADPTR register initialization value
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* @return Stack pointer that points to the stack frame
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*/
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FORCE_INLINE_ATTR UBaseType_t uxInitialiseStackFrame(UBaseType_t uxStackPointer, TaskFunction_t pxCode, void *pvParameters, uint32_t threadptr_reg_init)
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{
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/*
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Allocate space for the task's starting interrupt stack frame.
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- The stack frame must be allocated to a 16-byte aligned address.
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- We use RV_STK_FRMSZ (instead of sizeof(RvExcFrame)) as it rounds up the total size to a multiple of 16.
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*/
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uxStackPointer = STACKPTR_ALIGN_DOWN(16, uxStackPointer - RV_STK_FRMSZ);
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// Clear the entire interrupt stack frame
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RvExcFrame *frame = (RvExcFrame *)uxStackPointer;
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memset(frame, 0, sizeof(RvExcFrame));
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/*
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Initialize the stack frame.
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Note: Shifting RA into prvTaskExitError is necessary to make the GDB backtrace terminate inside that function.
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Otherwise, the backtrace will end in the function located just before prvTaskExitError in the address space.
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*/
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extern uint32_t __global_pointer$;
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frame->ra = (UBaseType_t)prvTaskExitError + 4; // size of the nop instruction at the beginning of prvTaskExitError
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frame->mepc = (UBaseType_t)pxCode;
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frame->a0 = (UBaseType_t)pvParameters;
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frame->gp = (UBaseType_t)&__global_pointer$;
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frame->tp = (UBaseType_t)threadptr;
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frame->tp = (UBaseType_t)threadptr_reg_init;
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return uxStackPointer;
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}
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StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
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{
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/*
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HIGH ADDRESS
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|---------------------------| <- pxTopOfStack on entry
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| TLS Variables |
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| ------------------------- | <- Start of useable stack
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| Starting stack frame |
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| ------------------------- | <- pxTopOfStack on return (which is the tasks current SP)
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| | |
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| | |
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| V |
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----------------------------- <- Bottom of stack
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LOW ADDRESS
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- All stack areas are aligned to 16 byte boundary
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- We use UBaseType_t for all of stack area initialization functions for more convenient pointer arithmetic
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*/
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UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
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// Initialize GCC TLS area
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uint32_t threadptr_reg_init;
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uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
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// Initialize the starting interrupt stack frame
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uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
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// Return the task's current stack pointer address which should point to the starting interrupt stack frame
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return (StackType_t *)uxStackPointer;
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//TODO: IDF-2393
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return (StackType_t *)frame;
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}
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// ------- Thread Local Storage Pointers Deletion Callbacks -------
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@@ -139,78 +139,161 @@ __attribute__((naked)) static void prvTaskExitError(void)
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_prvTaskExitError();
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}
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StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
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{
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extern uint32_t __global_pointer$;
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uint8_t *task_thread_local_start;
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uint8_t *threadptr;
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extern char _thread_local_start, _thread_local_end, _flash_rodata_start;
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/* Byte pointer, so that subsequent calculations don't depend on sizeof(StackType_t). */
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uint8_t *sp = (uint8_t *) pxTopOfStack;
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/* Set up TLS area.
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* The following diagram illustrates the layout of link-time and run-time
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* TLS sections.
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/**
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* @brief Align stack pointer in a downward growing stack
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*
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* +-------------+
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* |Section: | Linker symbols:
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* |.flash.rodata| ---------------
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* 0x0+-------------+ <-- _flash_rodata_start
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* ^ | |
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* | | Other data |
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* | | ... |
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* | +-------------+ <-- _thread_local_start
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* | |.tbss | ^
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* v | | |
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* 0xNNNN|int example; | | (thread_local_size)
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* |.tdata | v
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* +-------------+ <-- _thread_local_end
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* | Other data |
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* | ... |
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* | |
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* +-------------+
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*
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* Local variables of
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* pxPortInitialiseStack
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* -----------------------
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* +-------------+ <-- pxTopOfStack
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* |.tdata (*) | ^
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* ^ |int example; | |(thread_local_size
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* | | | |
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* | |.tbss (*) | v
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* | +-------------+ <-- task_thread_local_start
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* 0xNNNN | | | ^
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* | | | |
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* | | | |_thread_local_start - _rodata_start
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* | | | |
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* | | | v
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* v +-------------+ <-- threadptr
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*
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* (*) The stack grows downward!
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* This macro is used to round a stack pointer downwards to the nearest n-byte boundary, where n is a power of 2.
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* This macro is generally used when allocating aligned areas on a downward growing stack.
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*/
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#define STACKPTR_ALIGN_DOWN(n, ptr) ((ptr) & (~((n)-1)))
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uint32_t thread_local_sz = (uint32_t) (&_thread_local_end - &_thread_local_start);
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thread_local_sz = ALIGNUP(0x10, thread_local_sz);
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sp -= thread_local_sz;
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task_thread_local_start = sp;
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memcpy(task_thread_local_start, &_thread_local_start, thread_local_sz);
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threadptr = task_thread_local_start - (&_thread_local_start - &_flash_rodata_start);
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/**
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* @brief Allocate and initialize GCC TLS area
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*
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* This function allocates and initializes the area on the stack used to store GCC TLS (Thread Local Storage) variables.
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* - The area's size is derived from the TLS section's linker variables, and rounded up to a multiple of 16 bytes
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* - The allocated area is aligned to a 16-byte aligned address
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* - The TLS variables in the area are then initialized
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*
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* Each task access the TLS variables using the THREADPTR register plus an offset to obtain the address of the variable.
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* The value for the THREADPTR register is also calculated by this function, and that value should be use to initialize
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* the THREADPTR register.
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*
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* @param[in] uxStackPointer Current stack pointer address
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* @param[out] ret_threadptr_reg_init Calculated THREADPTR register initialization value
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* @return Stack pointer that points to the TLS area
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*/
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FORCE_INLINE_ATTR UBaseType_t uxInitialiseStackTLS(UBaseType_t uxStackPointer, uint32_t *ret_threadptr_reg_init)
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{
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/*
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TLS layout at link-time, where 0xNNN is the offset that the linker calculates to a particular TLS variable.
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/* Simulate the stack frame as it would be created by a context switch interrupt. */
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sp -= RV_STK_FRMSZ;
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RvExcFrame *frame = (RvExcFrame *)sp;
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memset(frame, 0, sizeof(*frame));
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/* Shifting RA into prvTaskExitError is necessary to make GDB backtrace ending inside that function.
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Otherwise backtrace will end in the function laying just before prvTaskExitError in address space. */
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frame->ra = (UBaseType_t)prvTaskExitError + 4/*size of the nop insruction at the beginning of prvTaskExitError*/;
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LOW ADDRESS
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|---------------------------| Linker Symbols
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| Section | --------------
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| .flash.rodata |
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0x0|---------------------------| <- _flash_rodata_start
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^ | Other Data |
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| |---------------------------| <- _thread_local_start
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| | .tbss | ^
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V | | |
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0xNNN | int example; | | tls_area_size
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| | |
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| .tdata | V
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|---------------------------| <- _thread_local_end
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| Other data |
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| ... |
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|---------------------------|
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HIGH ADDRESS
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*/
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// Calculate TLS area size and round up to multiple of 16 bytes.
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extern char _thread_local_start, _thread_local_end, _flash_rodata_start;
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const uint32_t tls_area_size = ALIGNUP(16, (uint32_t)&_thread_local_end - (uint32_t)&_thread_local_start);
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// TODO: check that TLS area fits the stack
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// Allocate space for the TLS area on the stack. The area must be aligned to 16-bytes
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uxStackPointer = STACKPTR_ALIGN_DOWN(16, uxStackPointer - (UBaseType_t)tls_area_size);
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// Initialize the TLS area with the initialization values of each TLS variable
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memcpy((void *)uxStackPointer, &_thread_local_start, tls_area_size);
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/*
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Calculate the THREADPTR register's initialization value based on the link-time offset and the TLS area allocated on
|
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the stack.
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HIGH ADDRESS
|
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|---------------------------|
|
||||
| .tdata (*) |
|
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^ | int example; |
|
||||
| | |
|
||||
| | .tbss (*) |
|
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| |---------------------------| <- uxStackPointer (start of TLS area)
|
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0xNNN | | | ^
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| | | |
|
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| ... | _thread_local_start - _rodata_start
|
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| | | |
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| | | V
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V | | <- threadptr register's value
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LOW ADDRESS
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*/
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*ret_threadptr_reg_init = (uint32_t)uxStackPointer - ((uint32_t)&_thread_local_start - (uint32_t)&_flash_rodata_start);
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return uxStackPointer;
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}
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/**
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* @brief Initialize the task's starting interrupt stack frame
|
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*
|
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* This function initializes the task's starting interrupt stack frame. The dispatcher will use this stack frame in a
|
||||
* context restore routine. Therefore, the starting stack frame must be initialized as if the task was interrupted right
|
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* before its first instruction is called.
|
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*
|
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* - The stack frame is allocated to a 16-byte aligned address
|
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*
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* @param[in] uxStackPointer Current stack pointer address
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* @param[in] pxCode Task function
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* @param[in] pvParameters Task function's parameter
|
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* @param[in] threadptr_reg_init THREADPTR register initialization value
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* @return Stack pointer that points to the stack frame
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*/
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FORCE_INLINE_ATTR UBaseType_t uxInitialiseStackFrame(UBaseType_t uxStackPointer, TaskFunction_t pxCode, void *pvParameters, uint32_t threadptr_reg_init)
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{
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/*
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Allocate space for the task's starting interrupt stack frame.
|
||||
- The stack frame must be allocated to a 16-byte aligned address.
|
||||
- We use XT_STK_FRMSZ (instead of sizeof(XtExcFrame)) as it rounds up the total size to a multiple of 16.
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*/
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uxStackPointer = STACKPTR_ALIGN_DOWN(16, uxStackPointer - RV_STK_FRMSZ);
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// Clear the entire interrupt stack frame
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RvExcFrame *frame = (RvExcFrame *)uxStackPointer;
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memset(frame, 0, sizeof(RvExcFrame));
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/*
|
||||
Initialize the stack frame.
|
||||
|
||||
Note: Shifting RA into prvTaskExitError is necessary to make the GDB backtrace terminate inside that function.
|
||||
Otherwise, the backtrace will end in the function located just before prvTaskExitError in the address space.
|
||||
*/
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extern uint32_t __global_pointer$;
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frame->ra = (UBaseType_t)prvTaskExitError + 4; // size of the nop instruction at the beginning of prvTaskExitError
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frame->mepc = (UBaseType_t)pxCode;
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frame->a0 = (UBaseType_t)pvParameters;
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frame->gp = (UBaseType_t)&__global_pointer$;
|
||||
frame->tp = (UBaseType_t)threadptr;
|
||||
frame->tp = (UBaseType_t)threadptr_reg_init;
|
||||
|
||||
return uxStackPointer;
|
||||
}
|
||||
|
||||
StackType_t *pxPortInitialiseStack(StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters)
|
||||
{
|
||||
/*
|
||||
HIGH ADDRESS
|
||||
|---------------------------| <- pxTopOfStack on entry
|
||||
| TLS Variables |
|
||||
| ------------------------- | <- Start of useable stack
|
||||
| Starting stack frame |
|
||||
| ------------------------- | <- pxTopOfStack on return (which is the tasks current SP)
|
||||
| | |
|
||||
| | |
|
||||
| V |
|
||||
----------------------------- <- Bottom of stack
|
||||
LOW ADDRESS
|
||||
|
||||
- All stack areas are aligned to 16 byte boundary
|
||||
- We use UBaseType_t for all of stack area initialization functions for more convenient pointer arithmetic
|
||||
*/
|
||||
|
||||
UBaseType_t uxStackPointer = (UBaseType_t)pxTopOfStack;
|
||||
|
||||
// Initialize GCC TLS area
|
||||
uint32_t threadptr_reg_init;
|
||||
uxStackPointer = uxInitialiseStackTLS(uxStackPointer, &threadptr_reg_init);
|
||||
|
||||
// Initialize the starting interrupt stack frame
|
||||
uxStackPointer = uxInitialiseStackFrame(uxStackPointer, pxCode, pvParameters, threadptr_reg_init);
|
||||
// Return the task's current stack pointer address which should point to the starting interrupt stack frame
|
||||
return (StackType_t *)uxStackPointer;
|
||||
//TODO: IDF-2393
|
||||
return (StackType_t *)frame;
|
||||
}
|
||||
|
||||
|
||||
|
||||
Reference in New Issue
Block a user