Messages in this thread | | | From | Bill Wendling <> | Date | Wed, 28 Apr 2021 12:21:38 -0700 | Subject | Re: [PATCH] arm64/vdso: Discard .note.gnu.property sections in vDSO |
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On Wed, Apr 28, 2021 at 10:40 AM Mark Brown <broonie@kernel.org> wrote: > On Wed, Apr 28, 2021 at 06:28:47PM +0100, Catalin Marinas wrote: > > On Fri, Apr 23, 2021 at 01:51:59PM -0700, Bill Wendling wrote: > > > > Since the note.gnu.property section in the vDSO is not checked by the > > > dynamic linker, discard the .note.gnu.property sections in the vDSO. > > > Can we not instead fix the linker script to preserve the > > .note.gnu.property, correctly aligned? It doesn't take much space and > > while we don't use it now, it has the BTI information about the binary. > > > Cc'ing a few others who were involved in the BTI support. > > Not just BTI, we also flag PAC usage in there too and could add other > extensions going forwards. While the note isn't actively used by > anything right now due to the kernel mapping the vDSO prior to userspace > starting it is part of the ABI and something could end up wanting to use > it and getting confused if it's not there. It would be much better to > fix the alignment issue.
If there's only one of the 8-byte aligned sections guaranteed, we could place it first in the note. Otherwise, we will have to change the alignment of the note (or somehow merge multiple notes).
-bw
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