Messages in this thread | | | From | "Bae, Chang Seok" <> | Subject | Re: [PATCH 14/15] x86/fsgsbase/64: Support legacy behavior when FS/GS updated by ptracer | Date | Thu, 22 Mar 2018 15:45:25 +0000 |
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On 3/21/18, 18:41, "Andy Lutomirski" <luto@kernel.org> wrote: > mov to gs changes GSBASE even if GS was unchanged. In GDB, ptrace (syscall) doesn't happen when FS/GS unchanged as its (context) cache seems to be first checked. This does not allow to preserve GSBASE as you know.
> But it's not clear to me that you've identified any case where > emulating this behavior is useful. One argument I heard is (if debugging a legacy application) user might want to (indirectly) access LDT during inferior call and this mov to fs/gs has been useful (maybe needed).
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