[tip:core/entry 2/3] arch/x86/include/asm/entry-common.h:43:24: error: call to undeclared function 'task_stack_page'; ISO C99 and later do not support implicit function declarations

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core/entry
head:   34ef6308418f138395a664bf9f5d80ace9825ac6
commit: 7fc04d7044aaa5ffe2afe78979fe6ddd5da24f10 [2/3] syscall_user_dispatch: Make it configurable in Kconfig
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20260708/[email protected]/config)
compiler: clang version 22.1.3 (https://github.com/llvm/llvm-project e9846648fd6183ee6d8cbdb4502213fcf902a211)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260708/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All errors (new ones prefixed by >>):

   In file included from arch/x86/kernel/idt.c:9:
   In file included from arch/x86/include/asm/traps.h:9:
   In file included from arch/x86/include/asm/idtentry.h:11:
   In file included from include/linux/entry-common.h:5:
>> arch/x86/include/asm/entry-common.h:43:24: error: call to undeclared function 'task_stack_page'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
      43 |                 WARN_ON_ONCE(regs != task_pt_regs(current));
         |                                      ^
   arch/x86/include/asm/processor.h:650:39: note: expanded from macro 'task_pt_regs'
     650 |         unsigned long __ptr = (unsigned long)task_stack_page(task);     \
         |                                              ^
   In file included from arch/x86/kernel/idt.c:9:
   In file included from arch/x86/include/asm/traps.h:9:
   In file included from arch/x86/include/asm/idtentry.h:11:
   In file included from include/linux/entry-common.h:8:
   In file included from include/linux/irq-entry-common.h:9:
   In file included from include/linux/syscalls.h:95:
   In file included from include/trace/syscall.h:7:
   In file included from include/linux/trace_events.h:10:
   In file included from include/linux/perf_event.h:25:
   In file included from arch/x86/include/asm/perf_event.h:721:
   In file included from arch/x86/include/asm/stacktrace.h:14:
   In file included from arch/x86/include/asm/switch_to.h:5:
>> include/linux/sched/task_stack.h:21:30: error: conflicting types for 'task_stack_page'
      21 | static __always_inline void *task_stack_page(const struct task_struct *task)
         |                              ^
   arch/x86/include/asm/entry-common.h:43:24: note: previous implicit declaration is here
      43 |                 WARN_ON_ONCE(regs != task_pt_regs(current));
         |                                      ^
   arch/x86/include/asm/processor.h:650:39: note: expanded from macro 'task_pt_regs'
     650 |         unsigned long __ptr = (unsigned long)task_stack_page(task);     \
         |                                              ^
   2 errors generated.


vim +/task_stack_page +43 arch/x86/include/asm/entry-common.h

167fd210ec0555 Thomas Gleixner 2020-07-23  12  
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  13  /* Check that the stack and regs on entry from user mode are sane. */
6d97af487dee31 Sven Schnelle   2022-05-04  14  static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs)
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  15  {
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  16  	if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) {
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  17  		/*
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  18  		 * Make sure that the entry code gave us a sensible EFLAGS
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  19  		 * register.  Native because we want to check the actual CPU
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  20  		 * state, not the interrupt state as imagined by Xen.
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  21  		 */
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  22  		unsigned long flags = native_save_fl();
662a0221893a3d Peter Zijlstra  2020-09-02  23  		unsigned long mask = X86_EFLAGS_DF | X86_EFLAGS_NT;
662a0221893a3d Peter Zijlstra  2020-09-02  24  
662a0221893a3d Peter Zijlstra  2020-09-02  25  		/*
662a0221893a3d Peter Zijlstra  2020-09-02  26  		 * For !SMAP hardware we patch out CLAC on entry.
662a0221893a3d Peter Zijlstra  2020-09-02  27  		 */
0bafc51babe234 Juergen Gross   2022-11-04  28  		if (cpu_feature_enabled(X86_FEATURE_SMAP) ||
0bafc51babe234 Juergen Gross   2022-11-04  29  		    cpu_feature_enabled(X86_FEATURE_XENPV))
662a0221893a3d Peter Zijlstra  2020-09-02  30  			mask |= X86_EFLAGS_AC;
662a0221893a3d Peter Zijlstra  2020-09-02  31  
662a0221893a3d Peter Zijlstra  2020-09-02  32  		WARN_ON_ONCE(flags & mask);
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  33  
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  34  		/* We think we came from user mode. Make sure pt_regs agrees. */
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  35  		WARN_ON_ONCE(!user_mode(regs));
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  36  
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  37  		/*
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  38  		 * All entries from user mode (except #DF) should be on the
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  39  		 * normal thread stack and should have user pt_regs in the
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  40  		 * correct location.
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  41  		 */
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  42  		WARN_ON_ONCE(!on_thread_stack());
27d6b4d14f5c3a Thomas Gleixner 2020-07-23 @43  		WARN_ON_ONCE(regs != task_pt_regs(current));
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  44  	}
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  45  }
6d97af487dee31 Sven Schnelle   2022-05-04  46  #define arch_enter_from_user_mode arch_enter_from_user_mode
27d6b4d14f5c3a Thomas Gleixner 2020-07-23  47  

:::::: The code at line 43 was first introduced by commit
:::::: 27d6b4d14f5c3ab21c4aef87dd04055a2d7adf14 x86/entry: Use generic syscall entry function

:::::: TO: Thomas Gleixner <[email protected]>
:::::: CC: Thomas Gleixner <[email protected]>

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