bitkeeper revision 1.1159.170.19 (419641c7PFSwb0OCvYznpBOaQJY6Fw)

Cleaned up debugger interface to traps.c.

1 files changed, 137 insertions, 0 deletions

diff --git a/xen/include/asm-x86/debugger.h b/xen/include/asm-x86/debugger.h
new file mode 100644
index 0000000000..b19e099a9f
--- /dev/null
+++ b/xen/include/asm-x86/debugger.h
@@ -0,0 +1,137 @@
+/******************************************************************************
+ * 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'.
+ */
+
+#ifndef __X86_DEBUGGER_H__
+#define __X86_DEBUGGER_H__
+
+/* Avoid magic vector numbers by using these semi-sensical names. */
+#define TRAP_divide_error     0
+#define TRAP_debug            1
+#define TRAP_nmi              2
+#define TRAP_int3             3
+#define TRAP_overflow         4
+#define TRAP_bounds           5
+#define TRAP_invalid_op       6
+#define TRAP_no_device        7
+#define TRAP_double_fault     8
+#define TRAP_copro_seg        9
+#define TRAP_invalid_tss     10
+#define TRAP_no_segment      11
+#define TRAP_stack_error     12
+#define TRAP_gp_fault        13
+#define TRAP_page_fault      14
+#define TRAP_spurious_int    15
+#define TRAP_copro_error     16
+#define TRAP_alignment_check 17
+#define TRAP_machine_check   18
+#define TRAP_simd_error      19
+
+/* The main trap handlers use these helper macros which include early bail. */
+#define DEBUGGER_trap_entry(_v, _r, _e) \
+    if ( debugger_trap_entry(_v, _r, _e) ) return;
+#define DEBUGGER_trap_fatal(_v, _r, _e) \
+    if ( debugger_trap_fatal(_v, _r, _e) ) return;
+
+#ifdef XEN_DEBUGGER
+
+#include <asm/pdb.h>
+
+static inline int debugger_trap_entry(
+    unsigned int vector, struct xen_regs *regs, unsigned int error_code)
+{
+    int ret = 0;
+
+    switch ( vector )
+    {
+    case TRAP_debug:
+        if ( pdb_initialized )
+        {
+            pdb_handle_debug_trap(regs, (long)error_code);
+            ret = 1; /* early exit */
+        }
+        break;
+
+    case TRAP_int3:
+        if ( pdb_initialized && (pdb_handle_exception(vector, regs) == 0) )
+            ret = 1; /* early exit */
+        break;
+
+    case TRAP_gp_fault:        
+        if ( ((regs->cs & 3) != 0) && ((error_code & 3) == 2) &&
+             pdb_initialized && (pdb_ctx.system_call != 0) )
+        {
+            unsigned long cr3 = read_cr3();
+            if ( cr3 == pdb_ctx.ptbr )
+                pdb_linux_syscall_enter_bkpt(
+                    regs, error_code, current->thread.traps + (error_code>>3));
+        }
+        break;
+    }
+
+    return ret;
+}
+
+static inline int debugger_trap_fatal(
+    unsigned int vector, struct xen_regs *regs, unsigned int error_code)
+{
+    int ret = 0;
+
+    switch ( vector )
+    {
+    case TRAP_page_fault:
+        if ( pdb_page_fault_possible )
+        {
+            pdb_page_fault = 1;
+            /* make eax & edx valid to complete the instruction */
+            regs->eax = (long)&pdb_page_fault_scratch;
+            regs->edx = (long)&pdb_page_fault_scratch;
+            ret = 1; /* exit - do not crash! */
+        }
+        break;
+    }
+
+    return ret;
+}
+
+#elif 0
+
+extern int kdb_trap(int, int, struct xen_regs *);
+
+static inline int debugger_trap_entry(
+    unsigned int vector, struct xen_regs *regs, unsigned int error_code)
+{
+    return 0;
+}
+
+static inline int debugger_trap_fatal(
+    unsigned int vector, struct xen_regs *regs, unsigned int error_code)
+{
+    return kdb_trap(vector, 0, regs);
+}
+
+#else
+
+#define debugger_trap_entry(_v, _r, _e) (0)
+#define debugger_trap_fatal(_v, _r, _e) (0)
+
+#endif
+
+#endif /* __X86_DEBUGGER_H__ */