From: Petr Tesarik <petr.tesarik.ext@huawei.com>

Linking with this object file it makes kexec_file_load(2) fail with:

 kexec_image: Unknown rela relocation: 20
 kexec_image: Error loading purgatory ret=-8

This is R_RISCV_GOT_HI20, generated by the linker to handle references to
the global variable _ctype from strcasecmp() and strncasecmp().

Rather than implementing GOT for the purgatory, remove the object file,
because it is not needed by the purgatory code.

Fixes: 838b3e28488f ("RISC-V: Load purgatory in kexec_file")
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: Li Zhengyu <lizhengyu3@huawei.com>
Cc: stable@vger.kernel.org
---
 arch/riscv/purgatory/Makefile | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index dc20e166983e..497bb72b6ba8 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile
@@ -1,15 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0
 OBJECT_FILES_NON_STANDARD := y
 
-purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o
+purgatory-y := purgatory.o sha256.o entry.o ctype.o memcpy.o memset.o
 purgatory-y += strcmp.o strlen.o strncmp.o
 
 targets += $(purgatory-y)
 PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))
 
-$(obj)/string.o: $(srctree)/lib/string.c FORCE
-	$(call if_changed_rule,cc_o_c)
-
 $(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
@@ -32,7 +29,6 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
 CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
-CFLAGS_string.o := -D__DISABLE_EXPORTS
 CFLAGS_ctype.o := -D__DISABLE_EXPORTS
 
 # When profile-guided optimization is enabled, llvm emits two different
@@ -83,9 +79,6 @@ CFLAGS_purgatory.o		+= $(PURGATORY_CFLAGS)
 CFLAGS_REMOVE_sha256.o		+= $(PURGATORY_CFLAGS_REMOVE)
 CFLAGS_sha256.o			+= $(PURGATORY_CFLAGS)
 
-CFLAGS_REMOVE_string.o		+= $(PURGATORY_CFLAGS_REMOVE)
-CFLAGS_string.o			+= $(PURGATORY_CFLAGS)
-
 CFLAGS_REMOVE_ctype.o		+= $(PURGATORY_CFLAGS_REMOVE)
 CFLAGS_ctype.o			+= $(PURGATORY_CFLAGS)
 
-- 
2.25.1

Hi Petr,

kernel test robot noticed the following build errors:

[auto build test ERROR on kees/for-next/pstore]
[also build test ERROR on kees/for-next/kspp linus/master v6.5-rc3 next-20230725]
[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/Petr-Tesarik/riscv-kexec-handle-R_RISCV_CALL_PLT-relocation-type/20230725-165116
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore
patch link:    https://lore.kernel.org/r/a083f38c7c3acd6ac9542228e36947be30b58188.1690274483.git.petr.tesarik.ext%40huawei.com
patch subject: [PATCH v1 3/3] riscv/purgatory: do not link with string.o
config: riscv-randconfig-r001-20230725 (https://download.01.org/0day-ci/archive/20230726/202307260325.E3Uh9dYf-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce: (https://download.01.org/0day-ci/archive/20230726/202307260325.E3Uh9dYf-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/202307260325.E3Uh9dYf-lkp@intel.com/

All errors (new ones prefixed by >>):

>> ld.lld: error: undefined symbol: memcmp
   >>> referenced by ctype.c
   >>>               arch/riscv/purgatory/purgatory.ro:(purgatory)

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

On Wed, 26 Jul 2023 03:36:39 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Petr,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on kees/for-next/pstore]
> [also build test ERROR on kees/for-next/kspp linus/master v6.5-rc3 next-20230725]
> [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/Petr-Tesarik/riscv-kexec-handle-R_RISCV_CALL_PLT-relocation-type/20230725-165116
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/pstore
> patch link:    https://lore.kernel.org/r/a083f38c7c3acd6ac9542228e36947be30b58188.1690274483.git.petr.tesarik.ext%40huawei.com
> patch subject: [PATCH v1 3/3] riscv/purgatory: do not link with string.o
> config: riscv-randconfig-r001-20230725 (https://download.01.org/0day-ci/archive/20230726/202307260325.E3Uh9dYf-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
> reproduce: (https://download.01.org/0day-ci/archive/20230726/202307260325.E3Uh9dYf-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/202307260325.E3Uh9dYf-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> ld.lld: error: undefined symbol: memcmp  
>    >>> referenced by ctype.c
>    >>>               arch/riscv/purgatory/purgatory.ro:(purgatory)  

Ah, I see... In my build, it was inlined by gcc (GCC-13), but I cannot
rely on that. Too bad...

OTOH I don't think it's worth implementing full support for GOT,
especially for functions that are not needed. I would rather either
write a RISC-V implementation of memcmp(), or split memcmp() from
lib/string.c.

Stay tuned for v2.

Petr T