[arm64:for-next/ghostbusters 9/19] arch/arm64/kernel/proton-pack.c:287:2: error: implicit declaration of function 'install_bp_hardening_cb'

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/ghostbusters
head:   9a313c5d65a5f10ddf605022e9220e52946326f0
commit: 13d4ca202f2cde01512b290eeaeee35938a7b351 [9/19] arm64: Rewrite Spectre-v2 mitigation code
config: arm64-randconfig-r023-20200920 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 6a6b06f5262bb96523eceef4a42fe8e60ae2a630)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/commit/?id=13d4ca202f2cde01512b290eeaeee35938a7b351
        git remote add arm64 https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
        git fetch --no-tags arm64 for-next/ghostbusters
        git checkout 13d4ca202f2cde01512b290eeaeee35938a7b351
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All errors (new ones prefixed by >>):

quoted

arch/arm64/kernel/proton-pack.c:287:2: error: implicit declaration of function 'install_bp_hardening_cb' [-Werror,-Wimplicit-function-declaration]

           install_bp_hardening_cb(cb);
           ^
   arch/arm64/kernel/proton-pack.c:303:2: error: implicit declaration of function 'install_bp_hardening_cb' [-Werror,-Wimplicit-function-declaration]
           install_bp_hardening_cb(qcom_link_stack_sanitisation);
           ^
   2 errors generated.

vim +/install_bp_hardening_cb +287 arch/arm64/kernel/proton-pack.c

   261	
   262	static enum mitigation_state spectre_v2_enable_fw_mitigation(void)
   263	{
   264		bp_hardening_cb_t cb;
   265		enum mitigation_state state;
   266	
   267		state = spectre_v2_get_cpu_fw_mitigation_state();
   268		if (state != SPECTRE_MITIGATED)
   269			return state;
   270	
   271		if (spectre_v2_mitigations_off())
   272			return SPECTRE_VULNERABLE;
   273	
   274		switch (arm_smccc_1_1_get_conduit()) {
   275		case SMCCC_CONDUIT_HVC:
   276			cb = call_hvc_arch_workaround_1;
   277			break;
   278	
   279		case SMCCC_CONDUIT_SMC:
   280			cb = call_smc_arch_workaround_1;
   281			break;
   282	
   283		default:
   284			return SPECTRE_VULNERABLE;
   285		}
   286	
 > 287		install_bp_hardening_cb(cb);
   288		return SPECTRE_MITIGATED;
   289	}
   290	

---
0-DAY CI Kernel Test Service, Intel Corporation
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