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- Clean up ddb_trap() somewhat, and handle exceptions that happen while we're

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in DDB (e.g. if a bad pointer was dereferenced; the debugger will recover).
- Change a comment to indicate that we are on the debugger stack when we get
  to ddb_trap().
- Fix possible buglet in computation of the branch target in db_branch_taken().
This commit is contained in:
thorpej 1999-04-20 21:19:48 +00:00
parent 701edb8db8
commit 869951571d
1 changed files with 12 additions and 40 deletions
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52
sys/arch/alpha/alpha/db_interface.c
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@ -1,4 +1,4 @@
/* $NetBSD: db_interface.c,v 1.5 1999/04/06 20:09:18 pk Exp $ */
/* $NetBSD: db_interface.c,v 1.6 1999/04/20 21:19:48 thorpej Exp $ */
/*
* Mach Operating System
@ -51,7 +51,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.5 1999/04/06 20:09:18 pk Exp $");
__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.6 1999/04/20 21:19:48 thorpej Exp $");
#include <sys/param.h>
#include <sys/proc.h>
@ -86,9 +86,6 @@ extern int trap_types;
int db_active = 0;
void ddbprinttrap __P((unsigned long, unsigned long, unsigned long,
unsigned long));
void db_mach_halt __P((db_expr_t, int, db_expr_t, char *));
void db_mach_reboot __P((db_expr_t, int, db_expr_t, char *));
@ -138,21 +135,7 @@ struct db_variable db_regs[] = {
struct db_variable *db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
/*
* Print trap reason.
*/
void
ddbprinttrap(a0, a1, a2, entry)
unsigned long a0, a1, a2, entry;
{
/* XXX Implement. */
printf("ddbprinttrap(0x%lx, 0x%lx, 0x%lx, 0x%lx)\n", a0, a1, a2,
entry);
}
/*
* ddb_trap - field a kernel trap
* ddb_trap - field a kernel trap
*/
int
ddb_trap(a0, a1, a2, entry, regs)
@ -161,25 +144,11 @@ ddb_trap(a0, a1, a2, entry, regs)
{
int s;
/*
* Don't bother checking for usermode, since a benign entry
* by the kernel (call to Debugger() or a breakpoint) has
* already checked for usermode. If neither of those
* conditions exist, something Bad has happened.
*/
if (entry != ALPHA_KENTRY_IF ||
(a0 != ALPHA_IF_CODE_BUGCHK && a0 != ALPHA_IF_CODE_BPT)) {
db_printf("ddbprinttrap from 0x%lx\n", /* XXX */
regs->tf_regs[FRAME_PC]);
ddbprinttrap(a0, a1, a2, entry);
(a0 != ALPHA_IF_CODE_BPT && a0 != ALPHA_IF_CODE_BUGCHK)) {
if (db_recover != 0) {
/*
* XXX Sould longjump back into command loop!
*/
db_printf("Faulted in DDB; continuing...\n");
alpha_pal_halt(); /* XXX */
db_error("Faulted in DDB; continuing...\n");
/* This will longjmp back into db_command_loop() */
db_error("Caught exception in ddb.\n");
/* NOTREACHED */
}
@ -191,7 +160,7 @@ ddb_trap(a0, a1, a2, entry, regs)
}
/*
* XXX Should switch to DDB's own stack, here.
* alpha_debug() switches us to the debugger stack.
*/
ddb_regs = *regs;
@ -252,7 +221,8 @@ db_write_bytes(addr, size, data)
void
Debugger()
{
asm("call_pal 0x81"); /* XXX bugchk */
__asm __volatile("call_pal 0x81"); /* bugchk */
}
/*
@ -524,6 +494,7 @@ db_branch_taken(ins, pc, regs)
db_addr_t pc;
db_regs_t *regs;
{
long signed_immediate;
alpha_instruction insn;
db_addr_t newpc;
@ -556,7 +527,8 @@ db_branch_taken(ins, pc, regs)
case op_bne:
case op_bge:
case op_bgt:
newpc = (insn.branch_format.displacement << 2) + (pc + 4);
signed_immediate = insn.branch_format.displacement;
newpc = (pc + 4) + (signed_immediate << 2);
break;
default: