Messages in this thread | | | Subject | Re: [PATCH 3/7] objtool: Add support for intra-function calls | From | Julien Thierry <> | Date | Fri, 3 Apr 2020 13:49:24 +0100 |
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On 4/3/20 1:41 PM, Peter Zijlstra wrote: > On Fri, Apr 03, 2020 at 09:01:38AM +0100, Julien Thierry wrote: >> >> Last I found is in qcom_link_stack_sanitization() [2], but that's just a >> workaround for a very specific hardware. In my local tree I just put the >> function as STACK_FRAME_NON_STANDARD. But the code just saves the return >> address, has 16 call instructions that just call the instruction after them, >> restores the return address and lets the C-function return normally (and it >> somehow fixes something for that hardware). >> > That sounds very much like the RSB flushing we do. >
Yes, the piece of code you posted reminded me of this. The difference is that the RSB part uses a loop and counter while the qcom thing has a fixed amount of call instructions (which can make things easier for static analysis, if we'd really want to go down that road).
-- Julien Thierry
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