Better siginfo fault codes for floating point exceptions on 88110, with

more work in progress to handle these exceptions correctly, and document
a new undocumented and evil chip bug while there.

6 files changed, 277 insertions, 23 deletions

diff --git a/sys/arch/aviion/include/fpu.h b/sys/arch/aviion/include/fpu.h
new file mode 100644
index 00000000000..fa7b95f0fab
--- /dev/null
+++ b/sys/arch/aviion/include/fpu.h
@@ -0,0 +1,3 @@
+/* $OpenBSD: fpu.h,v 1.1 2007/12/08 18:39:49 miod Exp $ */
+/* public domain */
+#include <m88k/fpu.h>
diff --git a/sys/arch/luna88k/include/fpu.h b/sys/arch/luna88k/include/fpu.h
new file mode 100644
index 00000000000..8493e1b3c62
--- /dev/null
+++ b/sys/arch/luna88k/include/fpu.h
@@ -0,0 +1,3 @@
+/* $OpenBSD: fpu.h,v 1.1 2007/12/08 18:39:50 miod Exp $ */
+/* public domain */
+#include <m88k/fpu.h>
diff --git a/sys/arch/m88k/include/fpu.h b/sys/arch/m88k/include/fpu.h
new file mode 100644
index 00000000000..1fd6c9e643d
--- /dev/null
+++ b/sys/arch/m88k/include/fpu.h
@@ -0,0 +1,40 @@
+/*	$OpenBSD: fpu.h,v 1.1 2007/12/08 18:39:50 miod Exp $	*/
+
+/*
+ * Copyright (c) 2007, Miodrag Vallat.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice, this permission notice, and the disclaimer below
+ * appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef	_M88K_FPU_H_
+#define	_M88K_FPU_H_
+
+/* FPECR bits */
+#define	FPECR_FIOV	0x80
+#define	FPECR_FUNIMP	0x40
+#define	FPECR_FPRV	0x20
+#define	FPECR_FROP	0x10
+#define	FPECR_FDVZ	0x08
+#define	FPECR_FUNF	0x04
+#define	FPECR_FOVF	0x02
+#define	FPECR_FINX	0x01
+
+/* FPSR and FPCR exception bits */
+#define	FPSR_EFINV	0x10
+#define	FPSR_EFDVZ	0x08
+#define	FPSR_EFUNF	0x04
+#define	FPSR_EFOVF	0x02
+#define	FPSR_EFINX	0x01
+
+#endif	/* _M88K_FPU_H_ */
diff --git a/sys/arch/m88k/m88k/m88110_fp.S b/sys/arch/m88k/m88k/m88110_fp.S
index 430a74d28a2..bd4116747b1 100644
--- a/sys/arch/m88k/m88k/m88110_fp.S
+++ b/sys/arch/m88k/m88k/m88110_fp.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: m88110_fp.S,v 1.3 2007/12/02 21:32:08 miod Exp $	*/
+/*	$OpenBSD: m88110_fp.S,v 1.4 2007/12/08 18:39:50 miod Exp $	*/
 
 /*
  * Copyright (c) 2007, Miodrag Vallat.
@@ -96,15 +96,137 @@ ASLOCAL(m88110_funimp)
 	bb1	PSR_FPU_DISABLE_BIT, r5, _ASM_LABEL(m88110_fpeflt)
 
 	/*
+	 * If this is a kernel fault, we were probably trying to reissue
+	 * a previously-faulting instruction.
+	 * Just return without altering the fpecr, the ``caller'' will
+	 * check it afterwards.
+	 */
+	bb1	PSR_SUPERVISOR_MODE_BIT, r5, _ASM_LABEL(m88110_fp_return_noreset)
+
+	/*
 	 * We should check the faulting instruction here.
-	 * This can be:
+	 *
+	 * According to the documentation, this can be:
 	 * - fsqrt (unimplemented)
 	 * - any valid fp instruction operating on an odd register pair
 	 * - any bogus fp instruction.
+	 *
+	 * However, real life shows that the 88110 will conveniently only
+	 * flag the ``unimplemented instruction'' exception bit, regardless
+	 * of the real exception cause. In this case, the fpsr register is
+	 * correctly populated. But since bits in it are sticky... we can
+	 * not trust its value )-:
+	 *
+	 * Because of this, we need to sort out real unimplemented opcodes
+	 * from incorrectly reported exceptions.
+	 * We will only handle odd register pairs for instructions issued
+	 * in user mode (since the kernel will not issue any fp instructions
+	 * except in this file).
 	 */
 
-	/* XXX TBD */
+#ifdef notyet
+	/* Fetch the offending instruction */
+	ld	r6,  r30, EF_EXIP * 4
+	ld.usr	r2,  r6,  r0
+
+	/*
+	 * Check the instruction format. All triadic floating point
+	 * instruction are built this way:
+	 *
+	 *	100001 | D | S1 | X | opcode | T1 | T2 | TD | S2
+	 *
+	 * with:
+	 * D (bits 25-21) = destination register
+	 * S1 (bits 20-16) = source 1 register
+	 * X (bit 15) = extended register file
+	 * T1 (bits 10-9), T2 (bits 8-7), TD (bits 6-5) = size of the
+	 *    respective registers (00 = single, 01 = double, 10 = X)
+	 * S1 (bits 4-0) = source 2 register
+	 *
+	 * flt is slightly different, in that the X bit is bit 9 (in T1).
+	 *
+	 * Note that we currently do not support the extended register
+	 * file, so instructions referring to the X registers will not
+	 * be processed. This includes all forms of the mov instruction.
+	 */
+
+	extu	r3,  r2,  6<26>
+	cmp	r4,  r3,  0x21	/* 10 0001 */
+	bcnd	ne0, r4,  _ASM_LABEL(m88110_bad_opcode)
+
+	/*
+	 * Extract the 4-bit opcode and check for the XRF bit.
+	 */
+	extu	r5,  r2,  4<11>	/* opcode */
+	cmp	r4,  r5,  0x04	/* flt */
+	bcnd	eq0, r4,  _ASM_LABEL(m88110_check_flt)
+
+	bb1	15,  r2,  _ASM_LABEL(m88110_bad_opcode)
+
+	/* For fcmp, we do not want to check TD. */
+	cmp	r4,  r5,  0x07	/* fcmp/fcmpu */
+	bcnd	eq0, r4,  _ASM_LABEL(m88110_check_t1)
+
+	/*
+	 * Check TD and RD. If TD is 01 and RD is not even,
+	 * this is indeed an odd-register pair exception.
+	 */
+	extu	r6,  r2,  2<5>
+	cmp	r7,  r6,  0x01
+	bcnd	ne0, r7,  _ASM_LABEL(m88110_check_t1)
+
+	bb1	21,  r2,  _ASM_LABEL(m88110_odd_reg)
+
+ASLOCAL(m88110_check_t1)
+	/*
+	 * Check T1 and R1. If T1 is 01 and R1 is not even,
+	 * this is indeed an odd-register pair exception.
+	 */
+	extu	r6,  r2,  2<9>
+	cmp	r7,  r6,  0x01
+	bcnd	ne0, r7,  _ASM_LABEL(m88110_check_t2)
+
+	bb1	16,  r2,  _ASM_LABEL(m88110_odd_reg)
 
+ASLOCAL(m88110_check_t2)
+	/*
+	 * Check T2 and R2. If T2 is 01 and R2 is not even,
+	 * this is indeed an odd-register pair exception.
+	 */
+	extu	r6,  r2,  2<7>
+	cmp	r7,  r6,  0x01
+	bcnd	ne0, r7,  _ASM_LABEL(m88110_bad_opcode)
+
+	bb1	 0,  r2,  _ASM_LABEL(m88110_odd_reg)
+
+	br	_ASM_LABEL(m88110_bad_opcode)
+
+ASLOCAL(m88110_check_flt)
+	/*
+	 * For flt, we only want to check TD. But we also want
+	 * to bail out if operating on XRF.
+	 */
+	bb1	9,   r2,  _ASM_LABEL(m88110_bad_opcode)
+
+	/*
+	 * Check TD and RD. If TD is 01 and RD is not even,
+	 * this is indeed an odd-register pair exception.
+	 */
+	extu	r6,  r2,  2<5>
+	cmp	r7,  r6,  0x01
+	bcnd	ne0, r7,  _ASM_LABEL(m88110_bad_opcode)
+
+	bb1	21,  r2,  _ASM_LABEL(m88110_odd_reg)
+
+ASLOCAL(m88110_bad_opcode)
+	/*
+	 * This is not an odd-register pair exception.
+	 *
+	 * We should check for an fsqrt instruction and emulate it.
+	 * However since the compiler will not produce it, we can
+	 * skip emulating it for now...
+	 */
+#endif
 	br	_ASM_LABEL(m88110_fpeflt)
 
 /*
@@ -230,10 +352,77 @@ ASLOCAL(m88110_finx)
 	 addu	r31, r31, 16
 
 ASLOCAL(m88110_fpeflt)
+	/*
+	 * Do not call trap() if the exception comes from kernel mode.
+	 */
+	ld	r5, r30, EF_EPSR * 4
+	bb1	PSR_SUPERVISOR_MODE_BIT, r5, _ASM_LABEL(m88110_fp_return)
+
 	or	r2, r0, T_FPEPFLT
 	bsr.n	_C_LABEL(m88110_trap)
 	 or	r3, r0, r30
 
+ASLOCAL(m88110_fp_return)
+	/*
+	 * Reset the exception cause register
+	 */
+	fstcr	r0,  FPECR
+
+ASLOCAL(m88110_fp_return_noreset)
 	ld	r1,  r31, 0
 	jmp.n	r1
 	 addu	r31, r31, 16
+
+#ifdef notyet
+/*
+ * Odd-numbered register pair emulation.
+ *
+ * On entry:
+ *	r2 = faulting instruction
+ *	r5 = instruction sub opcode (bits 14-11)
+ *	r30 = exception frame
+ *
+ * We'll issue a similar instruction using only even-numbered register pairs,
+ * update the exception frame registers with the result, and skip the
+ * emulated instruction.
+ */
+ASLOCAL(m88110_odd_reg)
+	or.u	r10, r0,  hi16(_ASM_LABEL(m88110_odd_table))
+	or	r10, r10, lo16(_ASM_LABEL(m88110_odd_table))
+	ld	r9,  r10 [r5]
+	jmp	r9
+
+ASLOCAL(m88110_odd_table)
+	.word	_ASM_LABEL(m88110_odd_fmul)
+	.word	_ASM_LABEL(m88110_odd_fcvt)
+	.word	_ASM_LABEL(m88110_bad_opcode)
+	.word	_ASM_LABEL(m88110_bad_opcode)
+
+	.word	_ASM_LABEL(m88110_odd_flt)
+	.word	_ASM_LABEL(m88110_odd_fadd)
+	.word	_ASM_LABEL(m88110_odd_fsub)
+	.word	_ASM_LABEL(m88110_odd_fcmp)
+
+	.word	_ASM_LABEL(m88110_bad_opcode)
+	.word	_ASM_LABEL(m88110_odd_int)
+	.word	_ASM_LABEL(m88110_odd_nint)
+	.word	_ASM_LABEL(m88110_odd_trnc)
+
+	.word	_ASM_LABEL(m88110_bad_opcode)
+	.word	_ASM_LABEL(m88110_bad_opcode)
+	.word	_ASM_LABEL(m88110_odd_fdiv)
+	.word	_ASM_LABEL(m88110_bad_opcode)
+
+ASLOCAL(m88110_odd_fmul)
+ASLOCAL(m88110_odd_fcvt)
+ASLOCAL(m88110_odd_flt)
+ASLOCAL(m88110_odd_fadd)
+ASLOCAL(m88110_odd_fsub)
+ASLOCAL(m88110_odd_fcmp)
+ASLOCAL(m88110_odd_int)
+ASLOCAL(m88110_odd_nint)
+ASLOCAL(m88110_odd_trnc)
+ASLOCAL(m88110_odd_fdiv)
+	/* XXX TBD */
+	br	_ASM_LABEL(m88110_fp_return)
+#endif
diff --git a/sys/arch/m88k/m88k/trap.c b/sys/arch/m88k/m88k/trap.c
index 67fcba101fe..b174e004e77 100644
--- a/sys/arch/m88k/m88k/trap.c
+++ b/sys/arch/m88k/m88k/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.58 2007/12/04 05:42:48 miod Exp $	*/
+/*	$OpenBSD: trap.c,v 1.59 2007/12/08 18:39:50 miod Exp $	*/
 /*
  * Copyright (c) 2004, Miodrag Vallat.
  * Copyright (c) 1998 Steve Murphree, Jr.
@@ -59,18 +59,19 @@
 
 #include <uvm/uvm_extern.h>
 
-#include <machine/asm_macro.h>   /* enable/disable interrupts */
+#include <machine/asm_macro.h>
 #include <machine/cmmu.h>
 #include <machine/cpu.h>
 #ifdef M88100
-#include <machine/m88100.h>		/* DMT_xxx */
-#include <machine/m8820x.h>		/* CMMU_PFSR_xxx */
+#include <machine/m88100.h>
+#include <machine/m8820x.h>
 #endif
 #ifdef M88110
 #include <machine/m88110.h>
 #endif
-#include <machine/pcb.h>		/* FIP_E, etc. */
-#include <machine/psl.h>		/* FIP_E, etc. */
+#include <machine/fpu.h>
+#include <machine/pcb.h>
+#include <machine/psl.h>
 #include <machine/trap.h>
 
 #include <machine/db_machdep.h>
@@ -236,7 +237,7 @@ m88100_trap(u_int type, struct trapframe *frame)
 		type += T_USER;
 		p->p_md.md_tf = frame;	/* for ptrace/signals */
 	}
-	fault_type = 0;
+	fault_type = SI_NOINFO;
 	fault_code = 0;
 	fault_addr = frame->tf_sxip & XIP_ADDR;
 
@@ -573,7 +574,7 @@ user_fault:
 		return;
 
 	if (sig) {
-		sv.sival_int = fault_addr;
+		sv.sival_ptr = (void *)fault_addr;
 		KERNEL_PROC_LOCK(p);
 		trapsignal(p, sig, fault_code, fault_type, sv);
 		KERNEL_PROC_UNLOCK(p);
@@ -613,7 +614,7 @@ m88110_trap(u_int type, struct trapframe *frame)
 	if ((p = curproc) == NULL)
 		p = &proc0;
 
-	fault_type = 0;
+	fault_type = SI_NOINFO;
 	fault_code = 0;
 	fault_addr = frame->tf_exip & XIP_ADDR;
 
@@ -728,16 +729,6 @@ m88110_trap(u_int type, struct trapframe *frame)
 		m88110_skip_insn(frame);
 		splx(s);
 		return;
-#if 0
-	case T_ILLFLT:
-		s = splhigh();
-		set_psr((psr = get_psr()) & ~PSR_IND);
-		ddb_error_trap(type == T_ILLFLT ? "unimplemented opcode" :
-		       "error fault", (db_regs_t*)frame);
-		set_psr(psr);
-		splx(s);
-		return;
-#endif /* 0 */
 #endif /* DDB */
 	case T_ILLFLT:
 		printf("Unimplemented opcode!\n");
@@ -1002,6 +993,8 @@ m88110_user_fault:
 		}
 		break;
 	case T_PRIVINFLT+T_USER:
+		fault_type = ILL_PRVREG;
+		/* FALLTHROUGH */
 	case T_ILLFLT+T_USER:
 #ifndef DDB
 	case T_KDB_BREAK:
@@ -1032,6 +1025,29 @@ m88110_user_fault:
 		break;
 	case T_FPEPFLT+T_USER:
 		sig = SIGFPE;
+
+		if (frame->tf_fpecr & FPECR_FUNIMP) {
+			if (frame->tf_epsr & PSR_SFD1)
+				fault_type = FPE_FLTINV;
+		} else if (frame->tf_fpecr & FPECR_FIOV)
+			fault_type = FPE_FLTSUB;
+		else if (frame->tf_fpecr & FPECR_FROP)
+			fault_type = FPE_FLTINV;
+		else if (frame->tf_fpecr & FPECR_FDVZ)
+			fault_type = FPE_INTDIV;
+		else if (frame->tf_fpecr & FPECR_FUNF) {
+			if (frame->tf_fpsr & FPSR_EFUNF)
+				fault_type = FPE_FLTUND;
+			else if (frame->tf_fpsr & FPSR_EFINX)
+				fault_type = FPE_FLTRES;
+		} else if (frame->tf_fpecr & FPECR_FOVF) {
+			if (frame->tf_fpsr & FPSR_EFOVF)
+				fault_type = FPE_FLTOVF;
+			else if (frame->tf_fpsr & FPSR_EFINX)
+				fault_type = FPE_FLTRES;
+		} else if (frame->tf_fpecr & FPECR_FINX)
+			fault_type = FPE_FLTRES;
+
 		/* skip trap instruction */
 		m88110_skip_insn(frame);
 		break;
@@ -1104,7 +1120,7 @@ m88110_user_fault:
 
 	if (sig) {
 deliver:
-		sv.sival_int = fault_addr;
+		sv.sival_ptr = (void *)fault_addr;
 		KERNEL_PROC_LOCK(p);
 		trapsignal(p, sig, fault_code, fault_type, sv);
 		KERNEL_PROC_UNLOCK(p);
diff --git a/sys/arch/mvme88k/include/fpu.h b/sys/arch/mvme88k/include/fpu.h
new file mode 100644
index 00000000000..8493e1b3c62
--- /dev/null
+++ b/sys/arch/mvme88k/include/fpu.h
@@ -0,0 +1,3 @@
+/* $OpenBSD: fpu.h,v 1.1 2007/12/08 18:39:50 miod Exp $ */
+/* public domain */
+#include <m88k/fpu.h>