[peterz-queue:x86/urgent 4/5] arch/x86/kernel/alternative.c:264:14: error: call to undeclared function 'its_alloc'; ISO C99 and later do not support implicit function declarations

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/urgent
head:   e87348e4a2daaf44da409991ca751e8844b27ef8
commit: 01c48b9466bf0ecf95821e3ea1a58b876c4e8aaf [4/5] x86/its: explicitly manage permissions for ITS pages
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20250606/202506060355.7UJHIyDa-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
rustc: rustc 1.78.0 (9b00956e5 2024-04-29)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250606/202506060355.7UJHIyDa-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/202506060355.7UJHIyDa-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/kernel/alternative.c:264:14: error: call to undeclared function 'its_alloc'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     264 |                 its_page = its_alloc();
         |                            ^
>> arch/x86/kernel/alternative.c:264:12: error: incompatible integer to pointer conversion assigning to 'void *' from 'int' [-Wint-conversion]
     264 |                 its_page = its_alloc();
         |                          ^ ~~~~~~~~~~~
   2 errors generated.


vim +/its_alloc +264 arch/x86/kernel/alternative.c

e52c1dc7455d32 Peter Zijlstra 2025-04-23  262  
872df34d7c51a7 Peter Zijlstra 2024-10-14  263  	if (!its_page || (its_offset + size - 1) >= PAGE_SIZE) {
872df34d7c51a7 Peter Zijlstra 2024-10-14 @264  		its_page = its_alloc();
872df34d7c51a7 Peter Zijlstra 2024-10-14  265  		if (!its_page) {
872df34d7c51a7 Peter Zijlstra 2024-10-14  266  			pr_err("ITS page allocation failed\n");
872df34d7c51a7 Peter Zijlstra 2024-10-14  267  			return NULL;
872df34d7c51a7 Peter Zijlstra 2024-10-14  268  		}
872df34d7c51a7 Peter Zijlstra 2024-10-14  269  		memset(its_page, INT3_INSN_OPCODE, PAGE_SIZE);
872df34d7c51a7 Peter Zijlstra 2024-10-14  270  		its_offset = 32;
872df34d7c51a7 Peter Zijlstra 2024-10-14  271  	}
872df34d7c51a7 Peter Zijlstra 2024-10-14  272  
872df34d7c51a7 Peter Zijlstra 2024-10-14  273  	/*
872df34d7c51a7 Peter Zijlstra 2024-10-14  274  	 * If the indirect branch instruction will be in the lower half
872df34d7c51a7 Peter Zijlstra 2024-10-14  275  	 * of a cacheline, then update the offset to reach the upper half.
872df34d7c51a7 Peter Zijlstra 2024-10-14  276  	 */
872df34d7c51a7 Peter Zijlstra 2024-10-14  277  	if ((its_offset + size - 1) % 64 < 32)
872df34d7c51a7 Peter Zijlstra 2024-10-14  278  		its_offset = ((its_offset - 1) | 0x3F) + 33;
872df34d7c51a7 Peter Zijlstra 2024-10-14  279  
872df34d7c51a7 Peter Zijlstra 2024-10-14  280  	thunk = its_page + its_offset;
872df34d7c51a7 Peter Zijlstra 2024-10-14  281  	its_offset += size;
872df34d7c51a7 Peter Zijlstra 2024-10-14  282  
872df34d7c51a7 Peter Zijlstra 2024-10-14  283  	return its_init_thunk(thunk, reg);
872df34d7c51a7 Peter Zijlstra 2024-10-14  284  }
872df34d7c51a7 Peter Zijlstra 2024-10-14  285  

:::::: The code at line 264 was first introduced by commit
:::::: 872df34d7c51a79523820ea6a14860398c639b87 x86/its: Use dynamic thunks for indirect branches

:::::: TO: Peter Zijlstra <peterz@infradead.org>
:::::: CC: Dave Hansen <dave.hansen@linux.intel.com>

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