On Wed, Mar 10, 2021 at 5:43 AM Jian Cai <jian...@google.com> wrote: > On Sat, Mar 6, 2021 at 4:25 AM Linus Walleij <linus.wall...@linaro.org> wrote: > > On Fri, Mar 5, 2021 at 12:23 AM Jian Cai <jian...@google.com> wrote: > > > On Wed, Mar 3, 2021 at 7:04 AM Linus Walleij <linus.wall...@linaro.org> > > > wrote:
> > > I think gcc also has these options. > > > https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html > > > > And how does that work with this part of your patch: > > > > +#define SLS_TEXT \ > > + ALIGN_FUNCTION(); \ > > + *(.text.__llvm_slsblr_thunk_*) > > > > This does not look compiler agnostic? > > You are right, GCC does generate different oraphan section names. I > will address it in the next version of the patch. Also it seems only > arm64 gcc supports -mharden-sls=* at this moment, arm32 gcc does not > support it yet. I don't know if there is any plan to implement it for > 32-bit gcc, but should we patch arm32 linker script preemptively, > assuming the sections will be named with the same pattern like how > clang does so the kernel would not fail to boot when the flag is > implemented? I think the best thing is to have something like this: Implement a macro such as this in include/linux/compiler-clang.h #define SLS_TEXT_SECTION *(.text.__llvm_slsblr_thunk_*) then the corresponding in include/linux/compiler-gcc.h but here also add a #define SLS_TEXT_SECTION #error "no compiler support" if the compiler version does not have this. I don't know the exact best approach sadly, as the patch looks now it seems a bit fragile, I wonder if you get linker warnings when this section is unused? Yours, Linus Walleij
