[peterz-queue:x86/core 2/3] arch/x86/kernel/alternative.c:2083:6: error: implicit declaration of function 'is_jcc32' is invalid in C99

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/core
head:   2eb791245b6ab0aa1bbc37537adb2b2c87f50651
commit: 13c5d94759ccacddeba3041d8c2c0c967becb5d3 [2/3] x86/alternative: Teach text_poke_bp() to patch Jcc.d32 instructions
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20230121/202301210331.s3pHXRMX-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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
        # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?id=13c5d94759ccacddeba3041d8c2c0c967becb5d3
        git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git
        git fetch --no-tags peterz-queue x86/core
        git checkout 13c5d94759ccacddeba3041d8c2c0c967becb5d3
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/kernel/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> arch/x86/kernel/alternative.c:2083:6: error: implicit declaration of function 'is_jcc32' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           if (is_jcc32(&insn)) {
               ^
   1 error generated.


vim +/is_jcc32 +2083 arch/x86/kernel/alternative.c

  2063	
  2064	static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
  2065				       const void *opcode, size_t len, const void *emulate)
  2066	{
  2067		struct insn insn;
  2068		int ret, i = 0;
  2069	
  2070		if (len == 6)
  2071			i = 1;
  2072		memcpy((void *)tp->text, opcode+i, len-i);
  2073		if (!emulate)
  2074			emulate = opcode;
  2075	
  2076		ret = insn_decode_kernel(&insn, emulate);
  2077		BUG_ON(ret < 0);
  2078	
  2079		tp->rel_addr = addr - (void *)_stext;
  2080		tp->len = len;
  2081		tp->opcode = insn.opcode.bytes[0];
  2082	
> 2083		if (is_jcc32(&insn)) {
  2084			/*
  2085			 * Map Jcc.d32 onto Jcc.d8 and use len to distinguish.
  2086			 */
  2087			tp->opcode = insn.opcode.bytes[1] - 0x10;
  2088		}
  2089	
  2090		switch (tp->opcode) {
  2091		case RET_INSN_OPCODE:
  2092		case JMP32_INSN_OPCODE:
  2093		case JMP8_INSN_OPCODE:
  2094			/*
  2095			 * Control flow instructions without implied execution of the
  2096			 * next instruction can be padded with INT3.
  2097			 */
  2098			for (i = insn.length; i < len; i++)
  2099				BUG_ON(tp->text[i] != INT3_INSN_OPCODE);
  2100			break;
  2101	
  2102		default:
  2103			BUG_ON(len != insn.length);
  2104		}
  2105	
  2106		switch (tp->opcode) {
  2107		case INT3_INSN_OPCODE:
  2108		case RET_INSN_OPCODE:
  2109			break;
  2110	
  2111		case CALL_INSN_OPCODE:
  2112		case JMP32_INSN_OPCODE:
  2113		case JMP8_INSN_OPCODE:
  2114		case 0x70 ... 0x7f: /* Jcc */
  2115			tp->disp = insn.immediate.value;
  2116			break;
  2117	
  2118		default: /* assume NOP */
  2119			switch (len) {
  2120			case 2: /* NOP2 -- emulate as JMP8+0 */
  2121				BUG_ON(memcmp(emulate, x86_nops[len], len));
  2122				tp->opcode = JMP8_INSN_OPCODE;
  2123				tp->disp = 0;
  2124				break;
  2125	
  2126			case 5: /* NOP5 -- emulate as JMP32+0 */
  2127				BUG_ON(memcmp(emulate, x86_nops[len], len));
  2128				tp->opcode = JMP32_INSN_OPCODE;
  2129				tp->disp = 0;
  2130				break;
  2131	
  2132			default: /* unknown instruction */
  2133				BUG();
  2134			}
  2135			break;
  2136		}
  2137	}
  2138	

-- 
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