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/******************************************************************************
* asm/debugger.h
*
* Generic hooks into arch-dependent Xen.
*
* Each debugger should define two functions here:
*
* 1. debugger_trap_entry():
* Called at start of any synchronous fault or trap, before any other work
* is done. The idea is that if your debugger deliberately caused the trap
* (e.g. to implement breakpoints or data watchpoints) then you can take
* appropriate action and return a non-zero value to cause early exit from
* the trap function.
*
* 2. debugger_trap_fatal():
* Called when Xen is about to give up and crash. Typically you will use this
* hook to drop into a debug session. It can also be used to hook off
* deliberately caused traps (which you then handle and return non-zero)
* but really these should be hooked off 'debugger_trap_entry'.
*
* 3. debugger_trap_immediate():
* Called if we want to drop into a debugger now. This is essentially the
* same as debugger_trap_fatal, except that we use the current register state
* rather than the state which was in effect when we took the trap.
* Essentially, if we're dying because of an unhandled exception, we call
* debugger_trap_fatal; if we're dying because of a panic() we call
* debugger_trap_immediate().
*/
#ifndef __X86_DEBUGGER_H__
#define __X86_DEBUGGER_H__
#include <asm/processor.h>
/* The main trap handlers use these helper macros which include early bail. */
#define DEBUGGER_trap_entry(_v, _r) \
if ( debugger_trap_entry(_v, _r) ) return EXCRET_fault_fixed;
#define DEBUGGER_trap_fatal(_v, _r) \
if ( debugger_trap_fatal(_v, _r) ) return EXCRET_fault_fixed;
#if defined(CRASH_DEBUG)
extern int __trap_to_cdb(struct cpu_user_regs *r);
#define debugger_trap_entry(_v, _r) (0)
static inline int debugger_trap_fatal(
unsigned int vector, struct cpu_user_regs *regs)
{
(void)__trap_to_cdb(regs);
return (vector == TRAP_int3); /* int3 is harmless */
}
/* Int3 is a trivial way to gather cpu_user_regs context. */
#define debugger_trap_immediate() __asm__ __volatile__ ( "int3" );
#elif defined(DOMU_DEBUG)
#include <xen/softirq.h>
static inline int debugger_trap_entry(
unsigned int vector, struct cpu_user_regs *regs)
{
struct vcpu *v = current;
if ( !KERNEL_MODE(ed, regs) || (ed->domain->domain_id == 0) )
return 0;
switch ( vector )
{
case TRAP_int3:
case TRAP_debug:
set_bit(_VCPUF_ctrl_pause, &ed->vcpu_flags);
raise_softirq(SCHEDULE_SOFTIRQ);
return 1;
}
return 0;
}
#define debugger_trap_fatal(_v, _r) (0)
#define debugger_trap_immediate()
#elif 0
extern int kdb_trap(int, int, struct cpu_user_regs *);
static inline int debugger_trap_entry(
unsigned int vector, struct cpu_user_regs *regs)
{
return 0;
}
static inline int debugger_trap_fatal(
unsigned int vector, struct cpu_user_regs *regs)
{
return kdb_trap(vector, 0, regs);
}
/* Int3 is a trivial way to gather cpu_user_regs context. */
#define debugger_trap_immediate() __asm__ __volatile__ ( "int3" );
#else
#define debugger_trap_entry(_v, _r) (0)
#define debugger_trap_fatal(_v, _r) (0)
#define debugger_trap_immediate()
#endif
#endif /* __X86_DEBUGGER_H__ */
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