Re: [PATCH v2 1/2] ARM: substitute OVERLAY description in linker script

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Mar 11, 2025 at 09:18:48AM +0100, Christian Eggers wrote:
> thanks for pushing this into the right direction.  Actually I didn't recognize that
> lld complains about overlapping virtual address ranges, maybe the .config provided
> by the first LKP report (which I used for testing) didn't enable the necessary options.

Right, it looks like CONFIG_HARDEN_BRANCH_HISTORY is not enabled in the
first configuration (since it was a randconfig) whereas it was in the
second configuration.

> On Monday, 10 March 2025, 21:37:29 CET, Nathan Chancellor wrote:
> > On Wed, Mar 05, 2025 at 02:49:38AM +0800, kernel test robot wrote:
> > > Hi Christian,
> > > 
> > > kernel test robot noticed the following build errors:
> > > 
> > > [auto build test ERROR on soc/for-next]
> > > [also build test ERROR on linus/master v6.14-rc5 next-20250304]
> > > [If your patch is applied to the wrong git tree, kindly drop us a note.
> > > And when submitting patch, we suggest to use '--base' as documented in
> > > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> > > 
> > > url:    https://github.com/intel-lab-lkp/linux/commits/Christian-Eggers/ARM-avoid-that-vectors-are-removed-during-linker-garbage-collection/20250224-210146
> > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
> > > patch link:    https://lore.kernel.org/r/20250224125414.2184-1-ceggers%40arri.de
> > > patch subject: [PATCH v2 1/2] ARM: substitute OVERLAY description in linker script
> > > config: arm-milbeaut_m10v_defconfig (https://download.01.org/0day-ci/archive/20250305/202503050230.820w99b6-lkp@intel.com/config)
> > > compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 14170b16028c087ca154878f5ed93d3089a965c6)
> > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250305/202503050230.820w99b6-lkp@intel.com/reproduce)
> > > 
> > > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > > the same patch/commit), kindly add following tags
> > > | Reported-by: kernel test robot <lkp@intel.com>
> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202503050230.820w99b6-lkp@intel.com/
> > > 
> > > All errors (new ones prefixed by >>):
> > > 
> > > >> ld.lld: error: section .vectors.bhb.bpiall virtual address range overlaps with .vectors.bhb.loop8
> > >    >>> .vectors.bhb.bpiall range is [0xFFFF0000, 0xFFFF001F]
> > >    >>> .vectors.bhb.loop8 range is [0xFFFF0000, 0xFFFF001F]
> > > --
> > > >> ld.lld: error: section .vectors.bhb.loop8 virtual address range overlaps with .vectors
> > >    >>> .vectors.bhb.loop8 range is [0xFFFF0000, 0xFFFF001F]
> > >    >>> .vectors range is [0xFFFF0000, 0xFFFF001F]
> > 
> > Looking at ld.lld's code, this error is intentionally ignored for
> > OVERLAY:
> > 
> > https://github.com/llvm/llvm-project/blob/9f170e6abed4a7b393bb8abbf07ac8d6930aa3b0/lld/ELF/Writer.cpp#L2751-L2761
> > 
> > I have submitted a patch that allows KEEP within OVERLAY to match GNU
> > ld:
> > 
> > https://github.com/llvm/llvm-project/pull/130661
> > 
> > Once/if that is accepted, we should go back to your v1 with something
> > like the following diff on top to keep things working for all linkers. I
> > hope that it won't take long for the ld.lld change to get reviewed and
> > landed but if this needs to be fixed urgently, this whole diff minus
> > '|| LLD_VERSION >= 210000' on the init/Kconfig change should work (with
> > a comment change). I can always send a follow up change to add it back.
> 
> 
> I build from an internal tree, so I am not in hurry.  As the Kconfig changes
> probably should take your Signed-Off-By, I am also fine if you do the necessary
> changes on my v1 and resubmit it together with your patch when it is time.

I landed the ld.lld change a little bit ago so I will go ahead and send
along my patch plus yours formally shortly.

https://github.com/llvm/llvm-project/commit/381599f1fe973afad3094e55ec99b1620dba7d8c

Thanks again for bringing this up.

Cheers,
Nathan