The following arc defconfig build warnings / errors noticed on today's Linux next-20240326 tag. Regressions: * arc - defconfig - gcc-9 build failed. Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx> Build log: --------- arch/arc/kernel/ptrace.c:342:16: warning: no previous prototype for 'syscall_trace_enter' [-Wmissing-prototypes] 342 | asmlinkage int syscall_trace_enter(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~ arch/arc/kernel/kprobes.c:193:15: warning: no previous prototype for 'arc_kprobe_handler' [-Wmissing-prototypes] 193 | int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~ In file included from arch/arc/include/asm/mmu.h:21, from arch/arc/include/asm/pgtable.h:14, from include/linux/pgtable.h:6, from include/asm-generic/io.h:1047, from arch/arc/include/asm/io.h:232, from include/linux/io.h:13, from kernel/dma/coherent.c:6: arch/arc/include/asm/mmu-arcv2.h: In function 'mmu_setup_asid': arch/arc/include/asm/mmu-arcv2.h:82:2: error: implicit declaration of function 'write_aux_reg' [-Werror=implicit-function-declaration] 82 | write_aux_reg(ARC_REG_PID, asid | MMU_ENABLE); | ^~~~~~~~~~~~~ cc1: some warnings being treated as errors Steps to reproduce: ------- # tuxmake --runtime podman --target-arch arc --toolchain gcc-9 --kconfig defconfig Links: - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240325/testrun/23149630/suite/build/test/gcc-9-defconfig/log - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240325/testrun/23149630/suite/build/test/gcc-9-defconfig/history/ - https://storage.tuxsuite.com/public/linaro/lkft/builds/2eA2VSZdDsL0DMBBhjoauN9IVoK/ -- Linaro LKFT https://lkft.linaro.org