2008-07-10 Till Straumann <strauman@slac.stanford.edu>

	* new-exceptions/bspsupport/ppc_exc_asm_macros.S,
	new-exceptions/bspsupport/ppc_exc_bspsupp.h,
	new-exceptions/bspsupport/ppc_exc_hdl.c,
	new-exceptions/bspsupport/vectors_init.c:
	fixed and enabled stack-switching algorithm which figures out
	if we already run on the ISR stack rather than relying on the
	_ISR_Nest_level.

	Added 'ppc_exc_crit_always_enabled' variable which defines
	the semantics of critical interrupts. Added a test to
	TEST_LOCK_crit so that calling ppc_exc_wrapup() (and
	possibly the dispatcher) is always skipped if the BSP/user
	wants to leave critical interrupts always enabled (at the
	expense of having no OS support).

	changed TEST_LOCK_mchk so that asynchronous machine-check
	handlers never call ppc_exc_wrapup() (and the dispatcher).
	We don't want to disable MSR_ME ever (to avoid checkstops)
	and hence asynchronous MEs must not use OS services anyways.

	added and commented new variables 'ppc_exc_intr_stack_size'
	'ppc_exc_crit_always_enabled'.

1 files changed, 18 insertions, 0 deletions

diff --git a/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/vectors_init.c b/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/vectors_init.c
index 86e2ca7c1f..dd80dd094d 100644
--- a/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/vectors_init.c
+++ b/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/vectors_init.c
@@ -337,11 +337,29 @@ int n = sizeof(exception_table)/sizeof(exception_table[0]);
 	/* Use current MMU / RI settings when running C exception handlers */
 	ppc_exc_msr_bits = _read_MSR() & ( MSR_DR | MSR_IR | MSR_RI );
 
+	/* Cache size of the interrupt stack in a SDA variable */
+	ppc_exc_intr_stack_size = rtems_configuration_get_interrupt_stack_size();
+
 	/* Copy into a SDA variable that is easy to access from
 	 * assembly code
 	 */
 	if ( ppc_cpu_is_bookE() ) {
 		ppc_exc_msr_irq_mask = MSR_EE | MSR_CE | MSR_DE ;
+		switch (ppc_exc_crit_always_enabled) {
+			case PPC_EXC_CRIT_NO_OS_SUPPORT:
+				_write_MSR(_read_MSR() | (MSR_CE | MSR_DE));
+			break;
+
+			case PPC_EXC_CRIT_OS_SUPPORT:
+				printk("ppc_exc: PPC_EXC_CRIT_OS_SUPPORT not yet implemented\n");
+				/* fall thru */
+
+			case PPC_EXC_CRIT_DISABLED:
+			default:
+				ppc_exc_crit_always_enabled = PPC_EXC_CRIT_DISABLED;
+				_write_MSR(_read_MSR() & ~(MSR_CE | MSR_DE));
+			break;
+		}
 	} else {
 		ppc_exc_msr_irq_mask = MSR_EE ;
 	}