9e2154ff1c
- Add constants for fields in DR6 and the reserved fields in DR7. Use these constants instead of magic numbers in most places that use DR6 and DR7. - Refer to T_TRCTRAP as "debug exception" rather than a "trace trap" as it is not just for trace exceptions. - Always read DR6 for debug exceptions and only clear TF in the flags register for user exceptions where DR6.BS is set. - Clear DR6 before returning from a debug exception handler as recommended by the SDM dating all the way back to the 386. This allows debuggers to determine the cause of each exception. For kernel traps, clear DR6 in the T_TRCTRAP case and pass DR6 by value to other parts of the handler (namely, user_dbreg_trap()). For user traps, wait until after trapsignal to clear DR6 so that userland debuggers can read DR6 via PT_GETDBREGS while the thread is stopped in trapsignal(). Reviewed by: kib, rgrimes MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D15189
91 lines
2.9 KiB
C
91 lines
2.9 KiB
C
/*-
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* Mach Operating System
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* Copyright (c) 1991,1990 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie Mellon
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* the rights to redistribute these changes.
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*
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* $FreeBSD$
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*/
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#ifndef _MACHINE_DB_MACHDEP_H_
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#define _MACHINE_DB_MACHDEP_H_
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#include <machine/frame.h>
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#include <machine/reg.h>
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#include <machine/trap.h>
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typedef vm_offset_t db_addr_t; /* address - unsigned */
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typedef int db_expr_t; /* expression - signed */
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#define PC_REGS() ((db_addr_t)(kdb_frame->tf_eflags & PSL_VM ? \
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(kdb_frame->tf_eip & 0xffff) + \
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((kdb_frame->tf_cs & 0xffff) << 4) : \
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kdb_frame->tf_eip))
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#define BKPT_INST 0xcc /* breakpoint instruction */
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#define BKPT_SIZE (1) /* size of breakpoint inst */
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#define BKPT_SET(inst) (BKPT_INST)
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#define BKPT_SKIP \
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do { \
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kdb_frame->tf_eip += 1; \
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kdb_thrctx->pcb_eip += 1; \
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} while(0)
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#define FIXUP_PC_AFTER_BREAK \
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do { \
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kdb_frame->tf_eip -= 1; \
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kdb_thrctx->pcb_eip -= 1; \
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} while(0);
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#define db_clear_single_step kdb_cpu_clear_singlestep
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#define db_set_single_step kdb_cpu_set_singlestep
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/*
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* The debug exception type is copied from %dr6 to 'code' and used to
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* disambiguate single step traps. Watchpoints have no special support.
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* Our hardware breakpoints are not well integrated with ddb and are too
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* different from watchpoints. ddb treats them as unknown traps with
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* unknown addresses and doesn't turn them off while it is running.
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*/
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#define IS_BREAKPOINT_TRAP(type, code) ((type) == T_BPTFLT)
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#define IS_SSTEP_TRAP(type, code) \
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((type) == T_TRCTRAP && (code) & DBREG_DR6_BS)
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#define IS_WATCHPOINT_TRAP(type, code) 0
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#define I_CALL 0xe8
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#define I_CALLI 0xff
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#define I_RET 0xc3
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#define I_IRET 0xcf
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#define inst_trap_return(ins) (((ins)&0xff) == I_IRET)
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#define inst_return(ins) (((ins)&0xff) == I_RET)
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#define inst_call(ins) (((ins)&0xff) == I_CALL || \
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(((ins)&0xff) == I_CALLI && \
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((ins)&0x3800) == 0x1000))
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#define inst_load(ins) 0
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#define inst_store(ins) 0
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int db_segsize(struct trapframe *tfp);
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#endif /* !_MACHINE_DB_MACHDEP_H_ */
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