FreeCalypso > hg > fc-tourmaline
view src/cs/services/cst/cst_stack.c @ 220:0ed36de51973
ABB semaphore protection overhaul
The ABB semaphone protection logic that came with TCS211 from TI
was broken in several ways:
* Some semaphore-protected functions were called from Application_Initialize()
context. NU_Obtain_Semaphore() called with NU_SUSPEND fails with
NU_INVALID_SUSPEND in this context, but the return value wasn't checked,
and NU_Release_Semaphore() would be called unconditionally at the end.
The latter call would increment the semaphore count past 1, making the
semaphore no longer binary and thus no longer effective for resource
protection. The fix is to check the return value from NU_Obtain_Semaphore()
and skip the NU_Release_Semaphore() call if the semaphore wasn't properly
obtained.
* Some SPI hardware manipulation was being done before entering the semaphore-
protected critical section. The fix is to reorder the code: first obtain
the semaphore, then do everything else.
* In the corner case of L1/DSP recovery, l1_abb_power_on() would call some
non-semaphore-protected ABB & SPI init functions. The fix is to skip those
calls in the case of recovery.
* A few additional corner cases existed, all of which are fixed by making
ABB semaphore protection 100% consistent for all ABB functions and code paths.
There is still one remaining problem of priority inversion: suppose a low-
priority task calls an ABB function, and some medium-priority task just happens
to preempt right in the middle of that semaphore-protected ABB operation. Then
the high-priority SPI task is locked out for a non-deterministic time until
that medium-priority task finishes its work and goes back to sleep. This
priority inversion problem remains outstanding for now.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Mon, 26 Apr 2021 20:55:25 +0000 |
parents | 4e78acac3d88 |
children |
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/******************************************************************************* * * CST_STACK.C * * Tasks and HISRs stacks monitoring. * * (C) Texas Instruments 2000 * ******************************************************************************/ #include <stdio.h> #include <string.h> #include "nucleus.h" #include "cs_defs.h" #include "tc_defs.h" // The following stack sizes are defined in int.s #define IRQ_STACK_SIZE 128 // Number of bytes in IRQ stack #define FIQ_STACK_SIZE 512 // Number of bytes in FIQ stack. #define SYSTEM_SIZE 1024 // Define the system stack size int vsi_o_trace (char * caller, unsigned long tclass, char * text); int vsi_t_sleep (char * caller, unsigned long tvalue); void CST_stack_trace() { int jndex, count, char_count; TC_TCB *head, *ptr; extern CS_NODE *TCD_Created_Tasks_List; extern CS_NODE *TCD_Created_HISRs_List; unsigned untouched; char *top_stack, *top, *bottom; extern char *TCT_System_Limit; char result[80]; char name[9]; vsi_o_trace("CST", 0x08, "Stack Info ..."); vsi_o_trace("CST", 0x08, " Name top bottom current untouched"); vsi_o_trace("CST", 0x08, "-------------------------------------------------"); for (jndex=0; jndex<2; jndex++) { // make use of TCB and HCB having same structure from beginning to past stack info if (jndex == 0) ptr = head = (TC_TCB *)TCD_Created_Tasks_List; else { ptr = head = (TC_TCB *)TCD_Created_HISRs_List; vsi_o_trace("CST", 0x08, "-------------------------------------------------"); } count = 0; do { untouched = 0; top_stack = (char *)ptr->tc_stack_start; while (*top_stack == 0xFE && top_stack <= (char *)ptr->tc_stack_end) { untouched++; top_stack++; } // Avoid to get a spurious character when tasks names are 8 characters long memcpy (name, ptr->tc_name, 8); name[8] = 0; sprintf(result, "%8s: %08x %08x %08x 0x%x", name, ptr->tc_stack_start, ptr->tc_stack_end, ptr->tc_stack_pointer, untouched); vsi_o_trace("CST", 0x08, result); vsi_t_sleep("",30); ptr = (TC_TCB*) ptr->tc_created.cs_next; } while (ptr != head && count++ < 50); //count is protection from infinite loops } // end of for (jndex=0; jndex<2; jndex++) // stack allocation algorithm from the int.s function INT_Initialize() // // \ \ // \----------\ // \ \ // \ \ // \ \ // \ SYSSTACK \ // \ \ // \ \ // \ \ // \----------\ // \ \ // \ IRQSTACK \ // \ \ // \----------\ // \ \ // \ \ // \ FIQSTACK \ // \ \ // \ \ // \----------\ // \ \ untouched = 0; top_stack = top = (char *)TCT_System_Limit; bottom = (char *) ((unsigned)TCT_System_Limit + SYSTEM_SIZE); while (*top_stack == 0xFE && top_stack <= bottom) { untouched++; top_stack++; } // "CST" being the current active task with its related CST_Stack, // the System Stack is unused (current sp_svc = System Stack Bottom) sprintf(result, "SYSSTACK: %08x %08x %08x 0x%x", top, bottom, bottom, // current sp_svc = System Stack Bottom untouched); vsi_o_trace("CST", 0x08, "-------------------------------------------------"); vsi_o_trace("CST", 0x08, result); vsi_t_sleep("",30); untouched = 0; top_stack = top = bottom + 4; bottom = (char *) ((unsigned)bottom + IRQ_STACK_SIZE); while (*top_stack == 0xFE && top_stack <= bottom) { untouched++; top_stack++; } // Since the processor is in supervisor mode (no IRQ & no FIQ), // current sp_irq = IRQ Stack bottom sprintf(result, "IRQSTACK: %08x %08x %08x 0x%x", top, bottom, bottom, // current sp_irq = IRQ Stack bottom untouched); vsi_o_trace("CST", 0x08, result); vsi_t_sleep("",30); untouched = 0; top_stack = top = bottom + 4; bottom = (char *) ((unsigned)bottom + FIQ_STACK_SIZE); while (*top_stack == 0xFE && top_stack <= bottom) { untouched++; top_stack++; } // Since the processor is in supervisor mode (no IRQ & no FIQ), // current sp_fiq = FIQ Stack bottom sprintf(result, "FIQSTACK: %08x %08x %08x 0x%x", top, bottom, bottom, // current sp_fiq = FIQ Stack bottom untouched); vsi_o_trace("CST", 0x08, result); vsi_o_trace("CST", 0x08, "-------------------------------------------------"); vsi_t_sleep("",30); }