Messages in this thread | | | Date | Tue, 10 Oct 2023 12:57:21 -0700 | From | Josh Poimboeuf <> | Subject | Re: [PATCH 1/3] Revert "x86/retpoline: Remove .text..__x86.return_thunk section" |
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On Tue, Oct 10, 2023 at 07:48:33PM +0200, Peter Zijlstra wrote: > On Tue, Oct 10, 2023 at 12:10:18PM -0500, David Kaplan wrote: > > > arch/x86/kernel/vmlinux.lds.S | 3 +++ > > arch/x86/lib/retpoline.S | 2 ++ > > 2 files changed, 5 insertions(+) > > > > diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S > > index 9cdb1a7332c4..54a5596adaa6 100644 > > --- a/arch/x86/kernel/vmlinux.lds.S > > +++ b/arch/x86/kernel/vmlinux.lds.S > > @@ -132,7 +132,10 @@ SECTIONS > > LOCK_TEXT > > KPROBES_TEXT > > SOFTIRQENTRY_TEXT > > +#ifdef CONFIG_RETPOLINE > > *(.text..__x86.indirect_thunk) > > + *(.text..__x86.return_thunk) > > +#endif > > STATIC_CALL_TEXT > > > > ALIGN_ENTRY_TEXT_BEGIN > > diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S > > index db813113e637..3da768a71cf9 100644 > > --- a/arch/x86/lib/retpoline.S > > +++ b/arch/x86/lib/retpoline.S > > @@ -129,6 +129,8 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array) > > > > #ifdef CONFIG_RETHUNK > > Perhaps elucidate the future reader with a comment here? Lest someone > tries removing it again.
Yes, please.
Also we could make objtool properly detect the non-relocated jump target. But this works for now.
-- Josh
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