[openeuler:openEuler-1.0-LTS 1636/1636] arch/x86/kernel/fpu/core.c:175:14: warning: mixing declarations and code is a C99 extension

16 May 2025

      tree:   https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS
head:   60611bd206ba7e11ef429b2653fdada76eff4d77
commit: 1e3cb18ebe2976b3294e85c3d162736cc3c7c92b [1636/1636] x86: Enhanced copy capabilities for Hygon processor
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20250516/202505160438.vuslIGAx-lkp@i...)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250516/202505160438.vuslIGAx-lkp@i...)

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/202505160438.vuslIGAx-lkp@intel.com/

All warnings (new ones prefixed by >>):

   arch/x86/kernel/fpu/core.c:149:14: warning: no previous prototype for function 'get_fpustate_free_space' [-Wmissing-prototypes]
     149 | unsigned int get_fpustate_free_space(struct fpu *fpu)
         |              ^
   arch/x86/kernel/fpu/core.c:149:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     149 | unsigned int get_fpustate_free_space(struct fpu *fpu)
         | ^
         | static
...
...
arch/x86/kernel/fpu/core.c:175:14: warning: mixing declarations and code is a C99 extension [-Wdeclaration-after-statement]
     175 |         struct fpu *fpu = ¤t->thread.fpu;
         |                     ^
   2 warnings generated.
vim +175 arch/x86/kernel/fpu/core.c

   144	
   145	#if defined(CONFIG_X86_HYGON_LMC_SSE2_ON) || \
   146		defined(CONFIG_X86_HYGON_LMC_AVX2_ON)
   147	
   148	extern unsigned int fpu_kernel_nonatomic_xstate_size;
...
149	unsigned int get_fpustate_free_space(struct fpu *fpu)
   150	{
   151		if ((fpu_kernel_xstate_size + fpu_kernel_nonatomic_xstate_size) >
   152		    sizeof(fpu->state))
   153			return 0;
   154		return fpu_kernel_nonatomic_xstate_size;
   155	}
   156	
   157	unsigned long get_fpu_registers_pos(struct fpu *fpu, unsigned int off)
   158	{
   159		unsigned long addr = 0;
   160	
   161		if (fpu && (fpu_kernel_nonatomic_xstate_size > off)) {
   162			addr = (unsigned long)&fpu->state.__padding[0];
   163			addr += fpu_kernel_xstate_size + off;
   164		}
   165		return addr;
   166	}
   167	
   168	/*
   169	 * We can call kernel_fpu_begin_nonatomic in non-atomic task context.
   170	 */
   171	int kernel_fpu_begin_nonatomic_mask(void)
   172	{
   173		preempt_disable();
   174	
175		struct fpu *fpu = ¤t->thread.fpu;
   176	
   177		/* we not support Nested call */
   178		if (test_thread_flag(TIF_USING_FPU_NONATOMIC))
   179			goto err;
   180	
   181		if (KERNEL_FPU_NONATOMIC_SIZE >
   182		    get_fpustate_free_space(¤t->thread.fpu))
   183			goto err;
   184	
   185		/*
   186	       * This means we call kernel_fpu_begin_nonatomic after kernel_fpu_begin,
   187	       * but before kernel_fpu_end.
   188	       */
   189		if (this_cpu_read(in_kernel_fpu))
   190			goto err;
   191	
   192		if (in_interrupt())
   193			goto err;
   194	
   195		if (current->flags & PF_KTHREAD)
   196			goto err;
   197	
   198		if (fpu->initialized)
   199			copy_fpregs_to_fpstate(¤t->thread.fpu);
   200	
   201		/* Set thread flag: TIC_USING_FPU_NONATOMIC */
   202		set_thread_flag(TIF_USING_FPU_NONATOMIC);
   203	
   204		__cpu_invalidate_fpregs_state();
   205	
   206		preempt_enable();
   207	
   208		return 0;
   209	
   210	err:
   211		preempt_enable();
   212	
   213		return -1;
   214	}
   215	EXPORT_SYMBOL_GPL(kernel_fpu_begin_nonatomic_mask);
   216
-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki