view src/gpf/osl/os_mem_ir.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
line wrap: on
line source

/*
 * This C module is a reconstruction based on the disassembly of
 * os_mem.obj in frame_na7_db_ir.lib from the Leonardo package.
 */

/* set of included headers from COFF symtab: */
#include <stdio.h>
#include <string.h>
#include "nucleus.h"
#include "typedefs.h"
#include "os.h"
#include "gdi.h"
#include "os_types.h"
#include "os_glob.h"

extern T_OS_PART_GRP_TABLE_ENTRY PartGrpTable[];
extern T_OS_POOL_BORDER PoolBorder[];

GLOBAL LONG
os_is_valid_partition(T_VOID_STRUCT *Buffer)
{
	int i;

	for (i = 0; i <= MaxPoolGroups; i++) {
		if (PoolBorder[i].End == 0)
			return(OS_ERROR);
		if ((char *)Buffer < PoolBorder[i].Start)
			continue;
		if ((char *)Buffer >= PoolBorder[i].End)
			continue;
		return(OS_OK);
	}
	return(OS_ERROR);
}

GLOBAL LONG
os_PartitionCheck(ULONG *ptr)
{
	PM_HEADER *phdr;
	PM_PCB *pool;

	phdr = (PM_HEADER *)(ptr - PPM_OFFSET - 2);
	if (phdr->pm_next_available)
		return(OS_PARTITION_FREE);
	pool = phdr->pm_partition_pool;
	if (ptr[((pool->pm_partition_size - 4) >> 2) - PPM_OFFSET] ==
			GUARD_PATTERN)
		return(OS_OK);
	else
		return(OS_PARTITION_GUARD_PATTERN_DESTROYED);
}

GLOBAL LONG
os_DeallocatePartition(OS_HANDLE TaskHandle, T_VOID_STRUCT *Buffer)
{
	if (os_is_valid_partition(Buffer) != OS_OK)
		return(OS_ERROR);
	if (NU_Deallocate_Partition(Buffer) != NU_SUCCESS)
		return(OS_ERROR);
	return(OS_OK);
}

GLOBAL LONG
os_AllocatePartition(OS_HANDLE TaskHandle, T_VOID_STRUCT **Buffer, ULONG Size,
		     ULONG Suspend, OS_HANDLE GroupHandle)
{
	T_OS_PART_POOL *pool, *requested_pool;
	ULONG nu_suspend;
	STATUS sts;
	int ret;

	for (pool = PartGrpTable[GroupHandle].grp_head; pool;
	     pool = pool->next)
		if (Size <= pool->size)
			break;
	if (!pool)
		return(OS_ERROR);
	requested_pool = pool;
	ret = OS_OK;
	nu_suspend = NU_NO_SUSPEND;
try_alloc:
	sts = NU_Allocate_Partition(&pool->pcb, (VOID **) Buffer, nu_suspend);
	switch (sts) {
	case NU_SUCCESS:
		return(ret);
	case NU_TIMEOUT:
	case NU_INVALID_SUSPEND:
		*Buffer = 0;
		return(OS_TIMEOUT);
	case NU_NO_PARTITION:
		pool = pool->next;
		if (pool) {
			ret = OS_ALLOCATED_BIGGER;
			goto try_alloc;
		}
		pool = requested_pool;
		if (Suspend) {
			nu_suspend = Suspend;
			ret = OS_WAITED;
			goto try_alloc;
		}
		return(OS_TIMEOUT);
	default:
		*Buffer = 0;
		return(OS_ERROR);
	}
}