On Tue, 2020-02-25 at 03:13:28 UTC, Michael Ellerman wrote: > We currently have two section mismatch warnings: > > The function __boot_from_prom() references > the function __init prom_init(). > > The function start_here_common() references > the function __init start_kernel(). > > The warnings are correct, we do have branches from non-init code into > init code, which is freed after boot. But we don't expect to ever > execute any of that early boot code after boot, if we did that would > be a bug. In particular calling into OF after boot would be fatal > because OF is no longer resident. > > So for now fix the warnings by marking the relevant functions as > __REF, which puts them in the ".ref.text" section. > > This causes some reordering of the functions in the final link: > > @@ -217,10 +217,9 @@ > c00000000000b088 t generic_secondary_common_init > c00000000000b124 t __mmu_off > c00000000000b14c t __start_initialization_multiplatform > -c00000000000b1ac t __boot_from_prom > -c00000000000b1ec t __after_prom_start > -c00000000000b260 t p_end > -c00000000000b27c T copy_and_flush > +c00000000000b1ac t __after_prom_start > +c00000000000b220 t p_end > +c00000000000b23c T copy_and_flush > c00000000000b300 T __secondary_start > c00000000000b300 t copy_to_here > c00000000000b344 t start_secondary_prolog > @@ -228,8 +227,9 @@ > c00000000000b36c t enable_64b_mode > c00000000000b388 T relative_toc > c00000000000b3a8 t p_toc > -c00000000000b3b0 t start_here_common > -c00000000000b3d0 t start_here_multiplatform > +c00000000000b3b0 t __boot_from_prom > +c00000000000b3f0 t start_here_multiplatform > +c00000000000b480 t start_here_common > c00000000000b880 T system_call_common > c00000000000b974 t system_call > c00000000000b9dc t system_call_exit > > In particular __boot_from_prom moves after copy_to_here, which means > it's not copied to zero in the first stage of copy of the kernel to > zero. > > But that's OK, because we only call __boot_from_prom before we do the > copy, so it makes no difference when it's copied. The call sequence > is: > __start > -> __start_initialization_multiplatform > -> __boot_from_prom > -> __start > -> __start_initialization_multiplatform > -> __after_prom_start > -> copy_and_flush > -> copy_and_flush (relocated to 0) > -> start_here_multiplatform > -> early_setup > > Reported-by: Mauricio Faria de Oliveira <mauri...@linux.ibm.com> > Reported-by: Roman Bolshakov <r.bolsha...@yadro.com> > Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
Applied to powerpc next. https://git.kernel.org/powerpc/c/6eeb9b3b9ce588f14a697737a30d0702b5a20293 cheers
