Messages in this thread | | | Date | Wed, 14 Mar 2018 13:24:06 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/1] x86/speculation, objtool: Annotate indirect calls/jumps for objtool on 32bit |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> On Wed, Mar 14, 2018 at 11:24:27AM +0000, Andy Whitcroft wrote: > > In 9e0e3c5130e9 ("x86/speculation, objtool: Annotate indirect calls/jumps > > for objtool") we added annotations for CALL_NOSPEC/JMP_NOSPEC on x86 64bit. > > We did not annotate the 32bit path. Annotate it similarly. > > > > Signed-off-by: Andy Whitcroft <apw@canonical.com> > > --- > > arch/x86/include/asm/nospec-branch.h | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > While reviewing indirect calls in our builds I noted that the > > i386 retpoline CALL_NOSPEC is not annotated safe even though > > its amd64 equivalent is. I cannot see any reason this is not > > also inherantly safe. Peter was there a reason that you did > > not annotate this one too? Anyhow, on the assumption this was > > just missed, this patch annotates it. > > Yeah, just an oversight aided by the fact that I (obviously) never build > 32bit kernels. > > > diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h > > index d0dabeae0505..07886162bdf8 100644 > > --- a/arch/x86/include/asm/nospec-branch.h > > +++ b/arch/x86/include/asm/nospec-branch.h > > @@ -183,7 +183,10 @@ > > * otherwise we'll run out of registers. We don't care about CET > > * here, anyway. > > */ > > -# define CALL_NOSPEC ALTERNATIVE("call *%[thunk_target]\n", \ > > +# define CALL_NOSPEC \ > > + ALTERNATIVE( \ > > + ANNOTATE_RETPOLINE_SAFE \ > > + "call *%[thunk_target]\n", \ > > " jmp 904f;\n" \ > > " .align 16\n" \ > > "901: call 903f;\n" \ > > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Applied, thanks guys!
Ingo
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