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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 05, 2020 at 06:21:00PM +0100, Mark Brown wrote: > On Tue, May 05, 2020 at 05:08:53PM +0100, Will Deacon wrote: > > On Tue, May 05, 2020 at 04:18:06PM +0100, Mark Brown wrote: > > > > > I also see a scary linker warning about the native VDSO: > > > > > aarch64-none-linux-gnu-ld: arch/arm64/kernel/vdso/vgettimeofday.o: warning: BTI turned on by -z force-bti when all inputs do not have BTI in NOTE section. > > > > I can't reproduce this, I am using clang-10 as well... can you share > > > your exact command line and config? I'm using > > > Just been debugging this, and it seems that not all clangs are created > > equal. Updating mine from 10.0.2 to 11.0.1 means I now get the > > '.note.gnu.property' sections emitted for C files compiled using > > '-mbranch-protection=pac-ret+leaf+bti', whereas I didn't before. > > Oh, that's irritating. I'm using clang from the llvm.org packages, > currently that's: > > 10.0.0-++20200115115127+cbe681bd833-1~exp1~20200115105727.528 > > so if this is a clang issue it looks like they fixed it in the clang-10 > branch. I'm not sure it's worth trying to detect and handle this or > not, I don't know how widely deployed toolchains that don't emit the > property are and there's a fairly clear solution. What do you think? The linker fixes this up when it warns, right? If so, I think the current behaviour is fine *but* we might want to improve the diagnostic a bit not to worry/confuse people. e.g. something like: "Your compiler is not emitting '.note.gnu.property' sections: forcing support for BTI in the linker, but consider upgrading your toolchain." Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel