[avpatel:riscv_trace_support_v5 88/104] arch/riscv/kernel/process.c:207:2: error: call to undeclared function 'flush_ptrace_hw_breakpoint'; ISO C99 and later do not support implicit function declarations

[kernel test robot <lkp@intel.com>]

tree:   https://github.com/avpatel/linux.git riscv_trace_support_v5
head:   1d99b155d3c1ca9a30209d51590db002a606f30c
commit: e0d276ca77744c881a75bbb741566d58b012bbe0 [88/104] riscv: ptrace support for hardware break/watchpoints
config: riscv-randconfig-r063-20260812 (https://download.01.org/0day-ci/archive/20260812/202608121737.Ik7QKY2w-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260812/202608121737.Ik7QKY2w-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/202608121737.Ik7QKY2w-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/riscv/kernel/process.c:16:
   In file included from include/linux/tick.h:8:
   In file included from include/linux/clockchips.h:14:
   In file included from include/linux/clocksource.h:22:
   In file included from arch/riscv/include/asm/io.h:148:
   include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
    1209 |         return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
         |                                                   ~~~~~~~~~~ ^
>> arch/riscv/kernel/process.c:207:2: error: call to undeclared function 'flush_ptrace_hw_breakpoint'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     207 |         flush_ptrace_hw_breakpoint(current);
         |         ^
   1 warning and 1 error generated.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for HAVE_MIXED_BREAKPOINTS_REGS
   Depends on [n]: HAVE_HW_BREAKPOINT [=n]
   Selected by [y]:
   - RISCV [=y]


vim +/flush_ptrace_hw_breakpoint +207 arch/riscv/kernel/process.c

   183	
   184	void flush_thread(void)
   185	{
   186	#ifdef CONFIG_FPU
   187		/*
   188		 * Reset FPU state and context
   189		 *	frm: round to nearest, ties to even (IEEE default)
   190		 *	fflags: accrued exceptions cleared
   191		 */
   192		fstate_off(current, task_pt_regs(current));
   193		memset(&current->thread.fstate, 0, sizeof(current->thread.fstate));
   194	#endif
   195	#ifdef CONFIG_RISCV_ISA_V
   196		/* Reset vector state */
   197		riscv_v_vstate_ctrl_init(current);
   198		riscv_v_vstate_off(task_pt_regs(current));
   199		kfree(current->thread.vstate.datap);
   200		memset(&current->thread.vstate, 0, sizeof(struct __riscv_v_ext_state));
   201		clear_tsk_thread_flag(current, TIF_RISCV_V_DEFER_RESTORE);
   202	#endif
   203	#ifdef CONFIG_RISCV_ISA_SUPM
   204		if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SUPM))
   205			envcfg_update_bits(current, ENVCFG_PMM, ENVCFG_PMM_PMLEN_0);
   206	#endif
 > 207		flush_ptrace_hw_breakpoint(current);
   208	}
   209	

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