On Thu, Mar 26, 2020 at 12:30:20PM -0700, H.J. Lu wrote: > In x86 kernel, .exit.text and .exit.data sections are discarded at > runtime, not by linker. Add RUNTIME_DISCARD_EXIT to generic DISCARDS > and define it in x86 kernel linker script to keep them. > > Signed-off-by: H.J. Lu <hjl.tools@xxxxxxxxx> > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > arch/x86/kernel/vmlinux.lds.S | 1 + > include/asm-generic/vmlinux.lds.h | 10 ++++++++-- > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S > index e3296aa028fe..7206e1ac23dd 100644 > --- a/arch/x86/kernel/vmlinux.lds.S > +++ b/arch/x86/kernel/vmlinux.lds.S > @@ -21,6 +21,7 @@ > #define LOAD_OFFSET __START_KERNEL_map > #endif > > +#define RUNTIME_DISCARD_EXIT > #define EMITS_PT_NOTE > #define RO_EXCEPTION_TABLE_ALIGN 16 > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index e00f41aa8ec4..6b943fb8c5fd 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -894,10 +894,16 @@ > * section definitions so that such archs put those in earlier section > * definitions. > */ > +#ifdef RUNTIME_DISCARD_EXIT > +#define EXIT_DISCARDS > +#else > +#define EXIT_DISCARDS \ > + EXIT_TEXT \ > + EXIT_DATA > +#endif /me goes back and reads the old thread on this... Kees, do you expect other arches to actually need this RUNTIME_DISCARD_EXIT thing or was that a hypothetical thing? /me searches more... oh, there's a patchset from you https://lkml.kernel.org/r/20200228002244.15240-1-keescook@xxxxxxxxxxxx which already contains this patch *and* an ARM64 patch which defines RUNTIME_DISCARD_EXIT so I'm guessing ARM64 wants to discard at runtime too. Which leaves the question why is H.J. sending that patch separate and you carry it in a patchset about orphan section warning? Seems like it wants to be in your patchset? Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
