- Replace RtlpGetExceptionAddress by the _ReturnAddress intrinsic and add it to ARM...

- Replace RtlpGetExceptionAddress by the _ReturnAddress intrinsic and add it to ARM intrin.h as it was missing.
- Simplify RtlpCheckForActiveDebugger: Remove the BOOLEAN parameter as we would always pass it FALSE. Always return FALSE false from kernel mode for simplicity.
- Fix a critical flaw in our exception support: RtlRaiseException and RtlRaiseStatus were implemented in C on x86. This lead to unpredictable register corruption because the compiler could not know that it had to preserve non-volatile registers before calling RtlCaptureContext as the saved context is later used to restore the caller in case the exception is handled and execution is continued. This made the functions unsafe to return from as any non-volatile register could be corrupted. Implement them in assembly for x86 to safely capture the context using only EBP and ESP. The C versions of those routines are still used and shared for the other architectures we support -- needs to be determined if this is safe and correct for those architectures.
- The ntdll exception Wine exposed this issue, and all tests now pass. The remaining failures on the build server are caused by missing or incomplete debug register support in KVM/QEMU. Run the test in another VM or on real hardware and all the tests will pass.
- Implement Debug Prompt (DbgPrompt) support for KD and KDBG. The KDBG implementation reads the prompt from keyboard or serial depending on the mode so that sysreg and rosdbg can support it too.
- Properly implement RtlAssert using DbgPrompt to prompt for the action to take instead of always doing a breakpoint. The new implementation is disabled until sysreg can support this. Also move RtlAssert to its own file as it has nothing to do with the error routines (nor does it belong in exception.c).
- Note that DbgPrompt was already used in PspCatchCriticalBreak, and this would have resulted in a silent hang as BREAKPOINT_PROMPT wasn't handled at all by KDBG.
- Implement KiRaiseAssertion (10 lines of code with the trap macros) and thus support NT_ASSERT. Add partial support for it to KDBG to print out a warning and the address of the failure, but don't do anything else. Also add NT_ASSERT to the DDK headers so that we can use it, but don't use it yet as the ARM method of performing this has not been decided nor implemented.
- KiTrap3 doesn't set STATUS_SUCCESS but BREAKPOINT_BREAK. They have the same numerical value but very different meaning -- BREAKPOINT_BREAK means that the exception is a software breakpoint and not a debug service call. Fix some comments to document that this is what is checked for.
- Fix inverted and broken logic in KdpReport. It would never pass second chance exceptions to the debugger, didn't respect the stop-on-exception flag properly and would always fail to handle some special exceptions in both first and second chance instead of just failing to handle it in first chance. Clean up, reformat and document what is going on.
- The DebugPrint and DebugPrompt support routines only perform a 2D interrupt on x86; use more portable comments.
- Add Alex to the programmer section of x86's kdsup.c -- he wrote KdpGetStateChange, KdpSetContextState and the code that was previously in KdpRead/WriteControlSpace.
- Add my name to the parts of KD where I have made significant work on getting KD/WinDbg support up and running.
- KD debugging is now quite functional and stable. Some bugs and stubs remain to be flushed out, but overall KD is now much better and easier to use than KDBG.

svn path=/trunk/; revision=43705