On 88110 processors, use a separate stack to handle NMI; these can occur

while we are switching pcbs and all sort of bad things could happen.

6 files changed, 103 insertions, 41 deletions

diff --git a/sys/arch/m88k/include/cpu.h b/sys/arch/m88k/include/cpu.h
index 7dae95065b7..96bd7a101e2 100644
--- a/sys/arch/m88k/include/cpu.h
+++ b/sys/arch/m88k/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.39 2008/12/21 21:43:51 miod Exp $ */
+/*	$OpenBSD: cpu.h,v 1.40 2009/02/08 21:40:56 miod Exp $ */
 /*
  * Copyright (c) 1996 Nivas Madhur
  * Copyright (c) 1992, 1993
@@ -110,7 +110,9 @@ struct cpu_info {
 #define	CI_DDB_PAUSE	3
 
 	int	ci_softintr;			/* pending soft interrupts */
-	u_int32_t ci_randseed;
+	u_int32_t ci_randseed;			/* per-cpu random seed */
+
+	vaddr_t	ci_nmi_stack;			/* NMI stack (88110) */
 
 #ifdef MULTIPROCESSOR
 
diff --git a/sys/arch/m88k/m88k/eh_common.S b/sys/arch/m88k/m88k/eh_common.S
index 84e27554050..011c60056f0 100644
--- a/sys/arch/m88k/m88k/eh_common.S
+++ b/sys/arch/m88k/m88k/eh_common.S
@@ -1,4 +1,4 @@
-/*   $OpenBSD: eh_common.S,v 1.46 2008/07/28 17:49:38 miod Exp $	*/
+/*   $OpenBSD: eh_common.S,v 1.47 2009/02/08 21:40:58 miod Exp $	*/
 /*
  * Mach Operating System
  * Copyright (c) 1993-1991 Carnegie Mellon University
@@ -222,10 +222,13 @@
  *	cause other exceptions to happen, and the whole system is
  *	in a rather precarious state and so special cautions must
  * 	be taken.
+ * The bit FLAG_NMI_STACK, on 88110, indicates that this exception
+ *	should be handled on the NMI stack.
  */
 #define FLAG_IGNORE_DATA_EXCEPTION	0
 #define FLAG_ENABLING_FPU		1
 #define FLAG_FROM_KERNEL		2
+#define	FLAG_NMI_STACK			3
 
 /* GENeral REGister OFFset into the E.F. (exception frame) */
 #define GENREG_OFF(num)		(EF_R0 + (num) * 4)
@@ -356,6 +359,8 @@
 #define	M88110_Data_Precheck \
 	bb1.n	FLAG_IGNORE_DATA_EXCEPTION, FLAGS, \
 	    _ASM_LABEL(m88110_ignore_data_exception);
+#define	M88110_NMI_Precheck \
+	set	FLAGS, FLAGS, 1<FLAG_NMI_STACK>
 
 #ifdef M88100
 /*
@@ -1598,9 +1603,9 @@ GLOBAL(m88110_fpu_handler)
 	or	r3, r0, r30
 	XCALL(_C_LABEL(m88110_trap), _ASM_LABEL(check_ast))
 
-/* MVME197 non-maskable interrupt handler (ABORT button) */
+/* non-maskable interrupt handler (IPIs, ABORT button) */
 GLOBAL(m88110_nonmaskable)
-	PREP88110("NMI", 11,)
+	PREP88110("NMI", 11, M88110_NMI_Precheck)
 	or	r2, r0, T_NON_MASK
 	or	r3, r0, r30
 	XCALL(_C_LABEL(interrupt), _ASM_LABEL(check_ast))
@@ -1813,7 +1818,7 @@ ASLOCAL(m88110_setup_phase_one)
 	/*
 	 * SR1: saved copy of exception-time register now holding FLAGS
 	 * SR2: saved copy of exception-time r1
-	 * SR3: must be preserved .. may be the exception-time stack
+	 * SR3: free
 	 * r1: return address to calling exception handler
 	 * FLAGS: CPU status flags
 	 *
@@ -1828,33 +1833,17 @@ ASLOCAL(m88110_setup_phase_one)
 	NOP
 	NOP
 
-	/* are we coming in from user mode? If so, pick up process pcb */
-	bb0	FLAG_FROM_KERNEL, FLAGS, _ASM_LABEL(m88110_pickup_stack)
-
-	/* Interrupt in kernel mode */
 	/*
-	 * SR1: saved copy of exception-time register now holding FLAGS
-	 * SR2: return address to the calling exception handler
-	 * SR3: must be preserved; may be important for other exceptions
-	 * FLAGS: CPU status flags
-	 *
-	 * immediate goal:
-	 *   We're already on the kernel stack, but not having
-	 *   needed to use SR3. We can just make room on the
-	 *   stack (r31) for our exception frame.
+	 * If we were in the kernel when the exception occured, we have
+	 * a valid stack. Keep using it.
 	 */
-	subu	r31,  r31,  TRAPFRAME_SIZEOF	/* r31 now our E.F. */
-	st	FLAGS,r31,  EF_FLAGS		/* save flags */
-	st	r1,   r31,  GENREG_OFF(1)	/* save prev. r1 (now free) */
+	bb1	FLAG_FROM_KERNEL, FLAGS, _ASM_LABEL(m88110_kernel_stack)
 
-	ldcr	r1,   SR3			/* save previous SR3 */
-	st	r1,   r31,  EF_SR3
-
-	addu	r1,   r31,  TRAPFRAME_SIZEOF	/* save previous r31 */
-	st	r1,   r31,  GENREG_OFF(31)
-	br	_ASM_LABEL(m88110_have_pcb)
+	/* is this an NMI? If so, pick the NMI stack */
+	bb1	FLAG_NMI_STACK, FLAGS, _ASM_LABEL(m88110_nmi_stack)
 
 ASLOCAL(m88110_pickup_stack)
+	/* Non-NMI exception in user mode */
 	/*
 	 * SR1: saved copy of exception-time register now holding FLAGS
 	 * SR2: return address to the calling exception handler
@@ -1862,9 +1851,7 @@ ASLOCAL(m88110_pickup_stack)
 	 * FLAGS: CPU status flags
 	 *
 	 * immediate goal:
-	 *   Since we're servicing an exception from user mode, we
-	 *   know that SR3 is free.  We use it to free up a temporary
-	 *   register to be used in getting the process pcb.
+	 *   Pick the process PCB and point our stack to it.
 	 */
 	stcr	r31,  SR3	/* save previous r31 */
 
@@ -1883,6 +1870,50 @@ ASLOCAL(m88110_pickup_stack)
 	st	r1,   r31,  GENREG_OFF(1)	/* save prev. r1 (now free)*/
 	ldcr	r1,   SR3			/* save previous r31 */
 	st	r1,   r31,  GENREG_OFF(31)
+	br	_ASM_LABEL(m88110_have_pcb)
+
+ASLOCAL(m88110_nmi_stack)
+	/* NMI exception in user mode */
+	/*
+	 * SR1: saved copy of exception-time register now holding FLAGS
+	 * SR2: return address to the calling exception handler
+	 * SR3: free
+	 * FLAGS: CPU status flags
+	 *
+	 * immediate goal:
+	 *   Pick the cpu NMI stack.
+	 */
+	stcr	r31,  SR3	/* save previous r31 */
+
+	/* switch to the NMI stack */
+	ldcr	r31,  CPU
+	ld	r31,  r31,  CI_NMI_STACK
+	addu	r31,  r31,  USPACE
+
+	subu	r31,  r31,  TRAPFRAME_SIZEOF	/* r31 now our E.F. */
+	st	FLAGS,r31,  EF_FLAGS		/* save flags */
+	st	r1,   r31,  GENREG_OFF(1)	/* save prev. r1 (now free) */
+	ldcr	r1,   SR3			/* save previous r31 */
+	st	r1,   r31,  GENREG_OFF(31)
+	br	_ASM_LABEL(m88110_have_pcb)
+
+ASLOCAL(m88110_kernel_stack)
+	/* Exception in kernel mode */
+	/*
+	 * SR1: saved copy of exception-time register now holding FLAGS
+	 * SR2: return address to the calling exception handler
+	 * SR3: free
+	 * FLAGS: CPU status flags
+	 *
+	 * immediate goal:
+	 *   We're already on the kernel stack.  We can just make room on the
+	 *   stack (r31) for our exception frame.
+	 */
+	subu	r31,  r31,  TRAPFRAME_SIZEOF	/* r31 now our E.F. */
+	st	FLAGS,r31,  EF_FLAGS		/* save flags */
+	st	r1,   r31,  GENREG_OFF(1)	/* save prev. r1 (now free) */
+	addu	r1,   r31,  TRAPFRAME_SIZEOF	/* save previous r31 */
+	st	r1,   r31,  GENREG_OFF(31)
 	/* FALLTHROUGH */
 
 ASLOCAL(m88110_have_pcb)
@@ -1897,6 +1928,10 @@ ASLOCAL(m88110_have_pcb)
 	 *   Exception-time r1, r31, FLAGS.
 	 *   Exception SR3, if appropriate.
 	 */
+
+	/* make sure that the FLAG_NMI_STACK bit is off */
+	clr	FLAGS, FLAGS, 1<FLAG_NMI_STACK>
+
 	stcr	TMP, SR3	/* free up TMP, TMP2, TMP3 */
 	SAVE_TMP2
 	SAVE_TMP3
@@ -1960,7 +1995,6 @@ ASLOCAL(m88110_setup_phase_two)
 	 *   Exception-time TMP2, TMP3.
 	 *   Exception-time espr, enip, exip.
 	 *   Exception number (EF_VECTOR).
-	 *   Exception SR3, if appropriate.
 	 *
 	 * immediate goal:
 	 *   restore the system to the exception-time state (except SR3 will
@@ -2016,7 +2050,6 @@ ASLOCAL(m88110_shadow_enable)
 	st	r30,  TMP,  GENREG_OFF(30)	/* save previous r30, r31 */
 	st	r31,  TMP,  GENREG_OFF(31)	/* save previous r30, r31 */
 	or	r31,  TMP,  r0			/* transfer E.F. pointer */
-	ld	TMP,  r31,  EF_SR3		/* get previous SR3 */
 	xcr	TMP,  TMP,  SR3			/* replace TMP, SR3 */
 
 	/* now save all regs to the exception frame. */
@@ -2054,7 +2087,7 @@ ASLOCAL(m88110_shadow_enable)
 	/*
 	 * SR1: free
 	 * SR2: free
-	 * SR3: previous exception-time SR3
+	 * SR3: free
 	 * r1: return address to the calling exception handler
 	 * r2 through r30: free
 	 * r31: our exception frame
@@ -2065,7 +2098,6 @@ ASLOCAL(m88110_shadow_enable)
 	 *   Exception-time espr, enip, exip.
 	 *   Exception number (EF_VECTOR).
 	 *   DSR/ISR
-	 *   Exception SR3, if appropriate.
 	 *
 	 * immediate goal:
 	 *   Put a copy of the exception frame pointer into r30
diff --git a/sys/arch/m88k/m88k/genassym.cf b/sys/arch/m88k/m88k/genassym.cf
index da3351166c0..05563cb829e 100644
--- a/sys/arch/m88k/m88k/genassym.cf
+++ b/sys/arch/m88k/m88k/genassym.cf
@@ -1,4 +1,4 @@
-#	$OpenBSD: genassym.cf,v 1.17 2007/12/22 17:14:39 miod Exp $
+#	$OpenBSD: genassym.cf,v 1.18 2009/02/08 21:40:58 miod Exp $
 #
 # Copyright (c) 1982, 1990 The Regents of the University of California.
 # All rights reserved.
@@ -28,7 +28,7 @@
 # SUCH DAMAGE.
 #
 #	@(#)genassym.c	7.8 (Berkeley) 5/7/91
-#	$Id: genassym.cf,v 1.17 2007/12/22 17:14:39 miod Exp $
+#	$Id: genassym.cf,v 1.18 2009/02/08 21:40:58 miod Exp $
 #
 
 include <sys/param.h>
@@ -69,6 +69,7 @@ member	ci_pfsr_d0
 member	ci_pfsr_d1
 member	ci_want_resched
 member	ci_softintr
+member	ci_nmi_stack
 
 # pcb fields
 struct	pcb
diff --git a/sys/arch/mvme88k/mvme88k/locore.S b/sys/arch/mvme88k/mvme88k/locore.S
index f7dc045a29a..291fee7edc5 100644
--- a/sys/arch/mvme88k/mvme88k/locore.S
+++ b/sys/arch/mvme88k/mvme88k/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.62 2008/10/30 22:06:59 miod Exp $	*/
+/*	$OpenBSD: locore.S,v 1.63 2009/02/08 21:40:58 miod Exp $	*/
 /*
  * Copyright (c) 2005, Miodrag Vallat.
  * Copyright (c) 1998 Steve Murphree, Jr.
@@ -328,6 +328,11 @@ ASGLOBAL(initstack)
 	space	USPACE
 ASGLOBAL(initstack_end)
 
+#ifdef M88110
+GLOBAL(nmi_stack)		/* NMI stack for the boot processor */
+	space	USPACE
+#endif
+
 #ifdef MULTIPROCESSOR
 	space	PAGE_SIZE	/* 4K, small, interim stack */
 ASLOCAL(slavestack_end)
diff --git a/sys/arch/mvme88k/mvme88k/m197_machdep.c b/sys/arch/mvme88k/mvme88k/m197_machdep.c
index e7cf6b7d774..f329cdeee56 100644
--- a/sys/arch/mvme88k/mvme88k/m197_machdep.c
+++ b/sys/arch/mvme88k/mvme88k/m197_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: m197_machdep.c,v 1.27 2008/09/19 20:18:03 miod Exp $	*/
+/*	$OpenBSD: m197_machdep.c,v 1.28 2009/02/08 21:40:58 miod Exp $	*/
 /*
  * Copyright (c) 1998, 1999, 2000, 2001 Steve Murphree, Jr.
  * Copyright (c) 1996 Nivas Madhur
@@ -201,8 +201,9 @@ m197_ext_int(u_int v, struct trapframe *eframe)
 		abort = *(u_int8_t *)(BS_BASE + BS_ABORT);
 		if (abort & BS_ABORT_INT) {
 			*(u_int8_t *)(BS_BASE + BS_ABORT) =
-			    abort | BS_ABORT_ICLR;
+			    (abort & ~BS_ABORT_IEN) | BS_ABORT_ICLR;
 			nmihand(eframe);
+			*(u_int8_t *)(BS_BASE + BS_ABORT) |= BS_ABORT_IEN;
 		}
 
 #ifdef MULTIPROCESSOR
diff --git a/sys/arch/mvme88k/mvme88k/machdep.c b/sys/arch/mvme88k/mvme88k/machdep.c
index b0350332c51..b67950eef54 100644
--- a/sys/arch/mvme88k/mvme88k/machdep.c
+++ b/sys/arch/mvme88k/mvme88k/machdep.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: machdep.c,v 1.215 2009/02/01 00:51:32 miod Exp $	*/
+/* $OpenBSD: machdep.c,v 1.216 2009/02/08 21:40:58 miod Exp $	*/
 /*
  * Copyright (c) 1998, 1999, 2000, 2001 Steve Murphree, Jr.
  * Copyright (c) 1996 Nivas Madhur
@@ -710,6 +710,20 @@ secondary_pre_main()
 		for (;;) ;
 	}
 
+	/*
+	 * On 88110 processors, allocate UPAGES contiguous pages for
+	 * the NMI handling stack.
+	 */
+	if (CPU_IS88110) {
+		ci->ci_nmi_stack = uvm_km_zalloc(kernel_map, USPACE);
+		if (ci->ci_nmi_stack == (vaddr_t)NULL) {
+			printf("cpu%d: unable to allocate NMI stack\n",
+			    ci->ci_cpuid);
+			__cpu_simple_unlock(&cpu_boot_mutex);
+			for (;;) ;
+		}
+	}
+
 	return (init_stack);
 }
 
@@ -990,6 +1004,13 @@ mvme_bootstrap()
 	set_cpu_number(master_cpu);
 	SET(curcpu()->ci_flags, CIF_ALIVE | CIF_PRIMARY);
 
+#ifdef M88110
+	if (CPU_IS88110) {
+		extern vaddr_t nmi_stack;
+		curcpu()->ci_nmi_stack = nmi_stack;
+	}
+#endif
+
 #ifdef M88100
 	if (CPU_IS88100) {
 		m88100_apply_patches();