[PATCH] D102472: [HWASAN] Update the tag info for X86_64

Mon May 24 10:53:02 PDT 2021

morehouse added a comment.

In D102472#2772657 <https://reviews.llvm.org/D102472#2772657>, @xiangzhangllvm wrote:

> 2 In fact, We can divide it into two steps, Step 1 is "Tag correctness checking", Step 2 is "Hardware supporting point with tag".
>
>    The option "ClUntagPointer" can help us first testing the Step 1.
>    For example: we write 7 in to int *p, for HWASAN, we do 2 things:
>    Step1:   Checking tag of p :
>                 call void @__hwasan_store4 (p_tagged)     // Checking tag is correct or not
>    Step2:   Write 7 into mem:
>                 *p_tagged = 7          // Need Hardware supporting.  But if we use "ClUntagPointer" change "*p_tagged = 7" --> "*p = 7", we can run the program, and test Step 1 for HWASAN.
>   
>   For HWASAN, Most code in compiler and compiler-rt is doing work for Step 1. So we can use "ClUntagPointer" first test it.
>   After we make sure Step 1 is OK, when the Hardware/OS is ready, we just need to totally/really enable HWASAN by just, I think, updating the system call in InitPrctl.

I recently removed a bunch of untagging stuff from our tests, and I'd like to avoid adding it back.  This is why I'm working on a buildbot to run tests in QEMU with LAM enabled.

I've also been testing locally with LAM in QEMU.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102472/new/

https://reviews.llvm.org/D102472