[PATCH 4/4] entry: Inline syscall_exit_to_user_mode()

[kernel test robot]

Hi Charlie,

kernel test robot noticed the following build errors:

[auto build test ERROR on ffd294d346d185b70e28b1a28abe367bbfe53c04]

url:    https://github.com/intel-lab-lkp/linux/commits/Charlie-Jenkins/riscv-entry-Convert-ret_from_fork-to-C/20250123-065957
base:   ffd294d346d185b70e28b1a28abe367bbfe53c04
patch link:    https://lore.kernel.org/r/20250122-riscv_optimize_entry-v1-4-4ee95559cfd0%40rivosinc.com
patch subject: [PATCH 4/4] entry: Inline syscall_exit_to_user_mode()
config: x86_64-randconfig-072-20250123 (https://download.01.org/0day-ci/archive/20250124/202501240101.mSdGpEoH-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250124/202501240101.mSdGpEoH-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501240101.mSdGpEoH-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/x86/include/asm/bug.h:99,
                    from include/linux/bug.h:5,
                    from include/linux/thread_info.h:13,
                    from include/linux/sched.h:14,
                    from arch/x86/mm/fault.c:7:
   include/linux/entry-common.h: In function 'syscall_exit_to_user_mode_work':
>> include/linux/entry-common.h:397:34: error: 'CONTEXT_KERNEL' undeclared (first use in this function); did you mean 'PERF_CONTEXT_KERNEL'?
     397 |         CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
         |                                  ^~~~~~~~~~~~~~
   include/asm-generic/bug.h:123:32: note: in definition of macro 'WARN_ON'
     123 |         int __ret_warn_on = !!(condition);                              \
         |                                ^~~~~~~~~
   include/linux/entry-common.h:397:9: note: in expansion of macro 'CT_WARN_ON'
     397 |         CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
         |         ^~~~~~~~~~
   include/linux/entry-common.h:397:34: note: each undeclared identifier is reported only once for each function it appears in
     397 |         CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
         |                                  ^~~~~~~~~~~~~~
   include/asm-generic/bug.h:123:32: note: in definition of macro 'WARN_ON'
     123 |         int __ret_warn_on = !!(condition);                              \
         |                                ^~~~~~~~~
   include/linux/entry-common.h:397:9: note: in expansion of macro 'CT_WARN_ON'
     397 |         CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
         |         ^~~~~~~~~~


vim +397 include/linux/entry-common.h

   378	
   379	/**
   380	 * syscall_exit_to_user_mode_work - Handle work before returning to user mode
   381	 * @regs:	Pointer to currents pt_regs
   382	 *
   383	 * Same as step 1 and 2 of syscall_exit_to_user_mode() but without calling
   384	 * exit_to_user_mode() to perform the final transition to user mode.
   385	 *
   386	 * Calling convention is the same as for syscall_exit_to_user_mode() and it
   387	 * returns with all work handled and interrupts disabled. The caller must
   388	 * invoke exit_to_user_mode() before actually switching to user mode to
   389	 * make the final state transitions. Interrupts must stay disabled between
   390	 * return from this function and the invocation of exit_to_user_mode().
   391	 */
   392	static __always_inline void syscall_exit_to_user_mode_work(struct pt_regs *regs)
   393	{
   394		unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
   395		unsigned long nr = syscall_get_nr(current, regs);
   396	
 > 397		CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
   398	
   399		if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
   400			if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr))
   401				local_irq_enable();
   402		}
   403	
   404		rseq_syscall(regs);
   405	
   406		/*
   407		 * Do one-time syscall specific work. If these work items are
   408		 * enabled, we want to run them exactly once per syscall exit with
   409		 * interrupts enabled.
   410		 */
   411		if (unlikely(work & SYSCALL_WORK_EXIT))
   412			syscall_exit_work(regs, work);
   413		local_irq_disable_exit_to_user();
   414		exit_to_user_mode_prepare(regs);
   415	}
   416	

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