freebsd-dev/sys/i386/include/db_machdep.h
Bruce Evans f434f3515b Fix printing of negative offsets (typically from frame pointers) again.
I fixed this in 1997, but the fix was over-engineered and fragile and
was broken in 2003 if not before.  i386 parameters were copied to 8
other arches verbatim, mostly after they stopped working on i386, and
mostly without the large comment saying how the values were chosen on
i386.  powerpc has a non-verbatim copy which just changes the uncritical
parameter and seems to add a sign extension bug to it.

Just treat negative offsets as offsets if they are no more negative than
-db_offset_max (default -64K), and remove all the broken parameters.

-64K is not very negative, but it is enough for frame and stack pointer
offsets since kernel stacks are small.

The over-engineering was mainly to go more negative than -64K for the
negative offset format, without affecting printing for more than a
single address.

Addresses in the top 64K of a (full 32-bit or 64-bit) address space
are now printed less well, but there aren't many interesting ones.
For arches that have many interesting ones very near the top (e.g.,
68k has interrupt vectors there), there would be no good limit for
the negative offset format and -64K is a good as anything.
2017-03-26 18:46:35 +00:00

89 lines
2.8 KiB
C

/*-
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*
* $FreeBSD$
*/
#ifndef _MACHINE_DB_MACHDEP_H_
#define _MACHINE_DB_MACHDEP_H_
#include <machine/frame.h>
#include <machine/trap.h>
typedef vm_offset_t db_addr_t; /* address - unsigned */
typedef int db_expr_t; /* expression - signed */
#define PC_REGS() ((db_addr_t)(kdb_frame->tf_eflags & PSL_VM ? \
(kdb_frame->tf_eip & 0xffff) + \
((kdb_frame->tf_cs & 0xffff) << 4) : \
kdb_frame->tf_eip))
#define BKPT_INST 0xcc /* breakpoint instruction */
#define BKPT_SIZE (1) /* size of breakpoint inst */
#define BKPT_SET(inst) (BKPT_INST)
#define BKPT_SKIP \
do { \
kdb_frame->tf_eip += 1; \
kdb_thrctx->pcb_eip += 1; \
} while(0)
#define FIXUP_PC_AFTER_BREAK \
do { \
kdb_frame->tf_eip -= 1; \
kdb_thrctx->pcb_eip -= 1; \
} while(0);
#define db_clear_single_step kdb_cpu_clear_singlestep
#define db_set_single_step kdb_cpu_set_singlestep
/*
* The debug exception type is copied from %dr6 to 'code' and used to
* disambiguate single step traps. Watchpoints have no special support.
* Our hardware breakpoints are not well integrated with ddb and are too
* different from watchpoints. ddb treats them as unknown traps with
* unknown addresses and doesn't turn them off while it is running.
*/
#define IS_BREAKPOINT_TRAP(type, code) ((type) == T_BPTFLT)
#define IS_SSTEP_TRAP(type, code) ((type) == T_TRCTRAP && (code) & 0x4000)
#define IS_WATCHPOINT_TRAP(type, code) 0
#define I_CALL 0xe8
#define I_CALLI 0xff
#define I_RET 0xc3
#define I_IRET 0xcf
#define inst_trap_return(ins) (((ins)&0xff) == I_IRET)
#define inst_return(ins) (((ins)&0xff) == I_RET)
#define inst_call(ins) (((ins)&0xff) == I_CALL || \
(((ins)&0xff) == I_CALLI && \
((ins)&0x3800) == 0x1000))
#define inst_load(ins) 0
#define inst_store(ins) 0
int db_segsize(struct trapframe *tfp);
#endif /* !_MACHINE_DB_MACHDEP_H_ */