Re: [RFC v2 0/3] Stack trace support in X64 exception handling

From: Andrew Fish <afish@apple.com>
To: Paulo Alcantara <pcacjr@zytor.com>
Cc: edk2-devel@lists.01.org, Rick Bramley <richard.bramley@hp.com>,
	Eric Dong <eric.dong@intel.com>, Laszlo Ersek <lersek@redhat.com>,
	Jeff Fan <jeff.fan@intel.com>
Subject: Re: [RFC v2 0/3] Stack trace support in X64 exception handling
Date: Wed, 15 Nov 2017 21:01:19 -0800	[thread overview]
Message-ID: <B5325DB9-6123-422F-8E0F-00474C1CEC20@apple.com> (raw)
In-Reply-To: <4c77020a-e01e-f048-9410-f474c6128601@zytor.com>

Paulo,

Those attached stack traces don't look right. 

Thanks,

Andrew Fish

> On Nov 15, 2017, at 5:46 PM, Paulo Alcantara <pcacjr@zytor.com> wrote:
> 
> Hi,
> 
> On 11/15/2017 11:18 PM, Paulo Alcantara wrote:
>> Hi,
>> This series adds stack trace support during a X64 CPU exception.
>> Informations like back trace, stack contents and image module names
>> (that were part of the call stack) will be dumped out.
>> We already have such support in ARM/AArch64 (IIRC) exception handling
>> (thanks to Ard), and then I thought we'd also deserve it in X64 and
>> IA-32 platforms.
>> What do you think guys?
>> BTW, I've tested this only with OVMF (X64 only), using:
>>   - gcc-6.3.0, GCC5, NOOPT
>> Any other tests  would be really appreciable.
>> Thanks!
>> Paulo
>> Repo:   https://github.com/pcacjr/edk2.git
>> Branch: stacktrace_v2
>> Cc: Rick Bramley <richard.bramley@hp.com>
>> Cc: Andrew Fish <afish@apple.com>
>> Cc: Eric Dong <eric.dong@intel.com>
>> Cc: Laszlo Ersek <lersek@redhat.com>
>> Cc: "Brian J. Johnson" <brian.johnson@hpe.com>
>> Cc: Jeff Fan <jeff.fan@intel.com>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
>> ---
>> v1 -> v2:
>>   * Add IA32 arch support (GCC toolchain only)
>>   * Replace hard-coded stack alignment value (16) with
>>     CPU_STACK_ALIGNMENT.
>>   * Check for proper stack and frame pointer alignments.
>>   * Fix initialization of UnwoundStacksCount to 1.
>>   * Move GetPdbFileName() to common code since it will be used by both
>>     IA32 and X64 implementations.
> 
> Sorry for the delay in sending v2. It's holiday here :-)
> 
> FWIW, I've attached two files which contain stack trace dumps of IA32 and X64 exceptions.
> 
> The new IA32 arch support is still limited to GCC only (that is, relying on frame pointers), but I'll start investing in a new solution that would work on both MSVC and GCC toolchains -- probably this weekend. If I come up with something, I'll let you know.
> 
> On IA32, I performed the same test as in X64 to trigger an NMI interrupt manually with: asm ("int $0x2") in PartitionDxe driver and watched out the call stack. The difference between the two dumps, regardless the CPU context, etc. is that we don't see the calls from PeiCore.dll. Then I figured out that the EIP gets a value of 0 before jumping to PartitionDxe's entry point.
> 
> I guess that's related to the "push $0" that Andrew mentioned earlier so the debugger knows when to stop unwinding. Although I can't see a "push 0" equivalent neither in SwitchStack.nasm nor in SwitchStack.asm for X64
> -- so we're able to see the calls within PeiCore.dll.
> 
> Thanks!
> Paulo
> <x64_dump.txt><ia32_dump.txt>_______________________________________________
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