Simplify ptrace branch handling code.

1 files changed, 41 insertions, 107 deletions

diff --git a/sys/arch/m88k/m88k/trap.c b/sys/arch/m88k/m88k/trap.c
index bfcda591eb7..9919a23355b 100644
--- a/sys/arch/m88k/m88k/trap.c
+++ b/sys/arch/m88k/m88k/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.25 2005/12/03 14:30:06 miod Exp $	*/
+/*	$OpenBSD: trap.c,v 1.26 2005/12/04 12:14:10 miod Exp $	*/
 /*
  * Copyright (c) 2004, Miodrag Vallat.
  * Copyright (c) 1998 Steve Murphree, Jr.
@@ -107,6 +107,7 @@ const char *trap_type[] = {
 };
 const int trap_types = sizeof trap_type / sizeof trap_type[0];
 
+#ifdef M88100
 const char *pbus_exception_type[] = {
 	"Success (No Fault)",
 	"unknown 1",
@@ -117,6 +118,7 @@ const char *pbus_exception_type[] = {
 	"Supervisor Violation",
 	"Write Violation",
 };
+#endif
 
 static inline void
 userret(struct proc *p, struct trapframe *frame, u_quad_t oticks)
@@ -258,9 +260,6 @@ m88100_trap(unsigned type, struct trapframe *frame)
 		break;
 	case T_INT:
 	case T_INT+T_USER:
-		/* This function pointer is set in machdep.c
-		   It calls m188_ext_int or sbc_ext_int depending
-		   on the value of brdtyp - smurph */
 		curcpu()->ci_intrdepth++;
 		md_interrupt_func(T_INT, frame);
 		curcpu()->ci_intrdepth--;
@@ -1111,15 +1110,6 @@ m88100_syscall(register_t code, struct trapframe *tf)
 	callp = p->p_emul->e_sysent;
 	nsys  = p->p_emul->e_nsysent;
 
-#ifdef DIAGNOSTIC
-	if (USERMODE(tf->tf_epsr) == 0)
-		panic("syscall");
-	if (curpcb != &p->p_addr->u_pcb)
-		panic("syscall curpcb/ppcb");
-	if (tf != (struct trapframe *)&curpcb->user_state)
-		panic("syscall trapframe");
-#endif
-
 	sticks = p->p_sticks;
 	p->p_md.md_tf = tf;
 
@@ -1269,15 +1259,6 @@ m88110_syscall(register_t code, struct trapframe *tf)
 	callp = p->p_emul->e_sysent;
 	nsys  = p->p_emul->e_nsysent;
 
-#ifdef DIAGNOSTIC
-	if (USERMODE(tf->tf_epsr) == 0)
-		panic("syscall");
-	if (curpcb != &p->p_addr->u_pcb)
-		panic("syscall curpcb/ppcb");
-	if (tf != (struct trapframe *)&curpcb->user_state)
-		panic("syscall trapframe");
-#endif
-
 	sticks = p->p_sticks;
 	p->p_md.md_tf = tf;
 
@@ -1363,13 +1344,6 @@ m88110_syscall(register_t code, struct trapframe *tf)
 
 	switch (error) {
 	case 0:
-		/*
-		 * If fork succeeded and we are the child, our stack
-		 * has moved and the pointer tf is no longer valid,
-		 * and p is wrong.  Compute the new trapframe pointer.
-		 * (The trap frame invariably resides at the
-		 * tippity-top of the u. area.)
-		 */
 		tf->tf_r[2] = rval[0];
 		tf->tf_r[3] = rval[1];
 		tf->tf_epsr &= ~PSR_C;
@@ -1467,12 +1441,9 @@ child_return(arg)
 
 #include <sys/ptrace.h>
 
-vaddr_t	ss_branch_taken(u_int, vaddr_t, u_int (*func)(u_int, struct reg *),
-	    struct reg *);
-u_int	ss_getreg_val(u_int, struct reg *);
+vaddr_t	ss_branch_taken(u_int, vaddr_t, struct reg *);
 int	ss_get_value(struct proc *, vaddr_t, u_int *);
-int	ss_inst_branch(unsigned);
-int	ss_inst_delayed(unsigned);
+int	ss_inst_branch_or_call(u_int);
 int	ss_put_breakpoint(struct proc *, vaddr_t, vaddr_t *, u_int *);
 
 #define	SYSCALL_INSTR	0xf000d080	/* tb0 0,r0,128 */
@@ -1514,114 +1485,78 @@ ss_put_value(struct proc *p, vaddr_t addr, u_int value)
 }
 
 /*
- * ss_branch_taken(instruction, program counter, func, func_data)
+ * ss_branch_taken(instruction, pc, regs)
  *
  * instruction will be a control flow instruction location at address pc.
  * Branch taken is supposed to return the address to which the instruction
- * would jump if the branch is taken. Func can be used to get the current
- * register values when invoked with a register number and func_data as
- * arguments.
+ * would jump if the branch is taken.
  *
- * If the instruction is not a control flow instruction, panic.
+ * This is different from branch_taken() in ddb, as we also need to process
+ * system calls.
  */
 vaddr_t
-ss_branch_taken(u_int inst, vaddr_t pc, u_int (*func)(u_int, struct reg *),
-    struct reg *func_data)
+ss_branch_taken(u_int inst, vaddr_t pc, struct reg *regs)
 {
-	/* check for system call */
-	if (inst == SYSCALL_INSTR) {
-		/*
-		 * The regular (pc + 4) breakpoint will match the error
-		 * return. Successfull system calls return at (pc + 8),
-		 * so we'll set up a branch breakpoint there.
-		 */
-		return (pc + 8);
-	}
+	u_int regno;
 
-	/* check if br/bsr */
-	if ((inst & 0xf0000000) == 0xc0000000) {
-		/* signed 26 bit pc relative displacement, shift left two bits */
+	/*
+	 * Quick check of the instruction. Note that we know we are only
+	 * invoked if ss_inst_branch_or_call() returns TRUE, so we do not
+	 * need to repeat the jpm, jsr and syscall stricter checks here.
+	 */
+	switch (inst >> (32 - 5)) {
+	case 0x18:	/* br */
+	case 0x19:	/* bsr */
+		/* signed 26 bit pc relative displacement, shift left 2 bits */
 		inst = (inst & 0x03ffffff) << 2;
 		/* check if sign extension is needed */
 		if (inst & 0x08000000)
 			inst |= 0xf0000000;
 		return (pc + inst);
-	}
 
-	/* check if bb0/bb1/bcnd case */
-	switch (inst & 0xf8000000) {
-	case 0xd0000000: /* bb0 */
-	case 0xd8000000: /* bb1 */
-	case 0xe8000000: /* bcnd */
-		/* signed 16 bit pc relative displacement, shift left two bits */
+	case 0x1a:	/* bb0 */
+	case 0x1b:	/* bb1 */
+	case 0x1d:	/* bcnd */
+		/* signed 16 bit pc relative displacement, shift left 2 bits */
 		inst = (inst & 0x0000ffff) << 2;
 		/* check if sign extension is needed */
 		if (inst & 0x00020000)
 			inst |= 0xfffc0000;
 		return (pc + inst);
-	}
-
-	/* check jmp/jsr case */
-	/* check bits 5-31, skipping 10 & 11 */
-	if ((inst & 0xfffff3e0) == 0xf400c000)
-		return (*func)(inst & 0x1f, func_data);	 /* the register value */
 
-	/* can't happen */
-	return (0);
-}
+	case 0x1e:	/* jmp or jsr */
+		regno = inst & 0x1f;	/* get the register value */
+		return (regno == 0 ? 0 : regs->r[regno]);
 
-/*
- * ss_getreg_val - handed a register number and an exception frame.
- *              Returns the value of the register in the specified
- *              frame. Only makes sense for general registers.
- */
-u_int
-ss_getreg_val(u_int regno, struct reg *regs)
-{
-	return (regno == 0 ? 0 : regs->r[regno]);
+	default:	/* system call */
+		/*
+		 * The regular (pc + 4) breakpoint will match the error
+		 * return. Successfull system calls return at (pc + 8),
+		 * so we'll set up a branch breakpoint there.
+		 */
+		return (pc + 8);
+	}
 }
 
 int
-ss_inst_branch(u_int ins)
+ss_inst_branch_or_call(u_int ins)
 {
 	/* check high five bits */
-
 	switch (ins >> (32 - 5)) {
 	case 0x18: /* br */
+	case 0x19: /* bsr */
 	case 0x1a: /* bb0 */
 	case 0x1b: /* bb1 */
 	case 0x1d: /* bcnd */
 		return (TRUE);
-		break;
-	case 0x1e: /* could be jmp */
-		if ((ins & 0xfffffbe0) == 0xf400c000)
+	case 0x1e: /* could be jmp or jsr */
+		if ((ins & 0xfffff3e0) == 0xf400c000)
 			return (TRUE);
 	}
 
 	return (FALSE);
 }
 
-/* ss_inst_delayed - this instruction is followed by a delay slot. Could be
-   br.n, bsr.n bb0.n, bb1.n, bcnd.n or jmp.n or jsr.n */
-
-int
-ss_inst_delayed(u_int ins)
-{
-	/* check the br, bsr, bb0, bb1, bcnd cases */
-	switch ((ins & 0xfc000000) >> (32 - 6)) {
-	case 0x31: /* br */
-	case 0x33: /* bsr */
-	case 0x35: /* bb0 */
-	case 0x37: /* bb1 */
-	case 0x3b: /* bcnd */
-		return (TRUE);
-	}
-
-	/* check the jmp, jsr cases */
-	/* mask out bits 0-4, bit 11 */
-	return (((ins & 0xfffff7e0) == 0xf400c400) ? TRUE : FALSE);
-}
-
 int
 ss_put_breakpoint(struct proc *p, vaddr_t va, vaddr_t *bpva, u_int *bpsave)
 {
@@ -1676,9 +1611,8 @@ process_sstep(struct proc *p, int sstep)
 	 * Find if this instruction may cause a branch, and set up a breakpoint
 	 * at the branch location.
 	 */
-	if (ss_inst_branch(instr) || inst_call(instr) || inst_return(instr) ||
-	    instr == SYSCALL_INSTR) {
-		brpc = ss_branch_taken(instr, pc, ss_getreg_val, sstf);
+	if (ss_inst_branch_or_call(instr) || instr == SYSCALL_INSTR) {
+		brpc = ss_branch_taken(instr, pc, sstf);
 
 		/* self-branches are hopeless */
 		if (brpc != pc && brpc != 0) {