Messages in this thread | | | From | Bill Wendling <> | Date | Wed, 28 Apr 2021 12:31:01 -0700 | Subject | Re: [PATCH] arm64/vdso: Discard .note.gnu.property sections in vDSO |
| |
On Wed, Apr 28, 2021 at 12:21 PM Bill Wendling <morbo@google.com> wrote: > 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). > I should have clarified that there's only one *entry* in the .note.gnu.properties section, and if not then is it possible to merge multiple entries into one. (Excuse my ignorance if this is already the case.)
-bw
| |