1 /******************************************************************************
2 * asm/debugger.h
3 *
4 * Generic hooks into arch-dependent Xen.
5 *
6 * Each debugger should define two functions here:
7 *
8 * 1. debugger_trap_entry():
9 * Called at start of any synchronous fault or trap, before any other work
10 * is done. The idea is that if your debugger deliberately caused the trap
11 * (e.g. to implement breakpoints or data watchpoints) then you can take
12 * appropriate action and return a non-zero value to cause early exit from
13 * the trap function.
14 *
15 * 2. debugger_trap_fatal():
16 * Called when Xen is about to give up and crash. Typically you will use this
17 * hook to drop into a debug session. It can also be used to hook off
18 * deliberately caused traps (which you then handle and return non-zero).
19 *
20 * 3. debugger_trap_immediate():
21 * Called if we want to drop into a debugger now. This is essentially the
22 * same as debugger_trap_fatal, except that we use the current register state
23 * rather than the state which was in effect when we took the trap.
24 * For example: if we're dying because of an unhandled exception, we call
25 * debugger_trap_fatal; if we're dying because of a panic() we call
26 * debugger_trap_immediate().
27 */
28
29 #ifndef __X86_DEBUGGER_H__
30 #define __X86_DEBUGGER_H__
31
32 #include <xen/sched.h>
33 #include <asm/regs.h>
34 #include <asm/processor.h>
35
36 #ifdef CONFIG_CRASH_DEBUG
37
38 #include <xen/gdbstub.h>
39
debugger_trap_fatal(unsigned int vector,struct cpu_user_regs * regs)40 static inline bool debugger_trap_fatal(
41 unsigned int vector, struct cpu_user_regs *regs)
42 {
43 int rc = __trap_to_gdb(regs, vector);
44 return ((rc == 0) || (vector == TRAP_int3));
45 }
46
47 /* Int3 is a trivial way to gather cpu_user_regs context. */
48 #define debugger_trap_immediate() __asm__ __volatile__ ( "int3" );
49
50 #else
51
debugger_trap_fatal(unsigned int vector,struct cpu_user_regs * regs)52 static inline bool debugger_trap_fatal(
53 unsigned int vector, struct cpu_user_regs *regs)
54 {
55 return false;
56 }
57
58 #define debugger_trap_immediate() ((void)0)
59
60 #endif
61
debugger_trap_entry(unsigned int vector,struct cpu_user_regs * regs)62 static inline bool debugger_trap_entry(
63 unsigned int vector, struct cpu_user_regs *regs)
64 {
65 /*
66 * This function is called before any checks are made. Amongst other
67 * things, be aware that during early boot, current is not a safe pointer
68 * to follow.
69 */
70 struct vcpu *v = current;
71
72 if ( vector != TRAP_int3 && vector != TRAP_debug )
73 return false;
74
75 if ( guest_mode(regs) && guest_kernel_mode(v, regs) &&
76 v->domain->debugger_attached )
77 {
78 if ( vector != TRAP_debug ) /* domain pause is good enough */
79 current->arch.gdbsx_vcpu_event = vector;
80 domain_pause_for_debugger();
81 return true;
82 }
83
84 return false;
85 }
86
87 unsigned int dbg_rw_mem(void * __user addr, void * __user buf,
88 unsigned int len, domid_t domid, bool toaddr,
89 uint64_t pgd3);
90
91 #endif /* __X86_DEBUGGER_H__ */
92