Re: [PATCH v1 1/1] x86/fred/signal: Prevent single-step upon ERETU completion

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

Hi Xin,

kernel test robot noticed the following build errors:

[auto build test ERROR on 6a7c3c2606105a41dde81002c0037420bc1ddf00]

url:    https://github.com/intel-lab-lkp/linux/commits/Xin-Li-Intel/x86-fred-signal-Prevent-single-step-upon-ERETU-completion/20250522-140954
base:   6a7c3c2606105a41dde81002c0037420bc1ddf00
patch link:    https://lore.kernel.org/r/20250522060549.2882444-1-xin%40zytor.com
patch subject: [PATCH v1 1/1] x86/fred/signal: Prevent single-step upon ERETU completion
config: i386-buildonly-randconfig-003-20250522 (https://download.01.org/0day-ci/archive/20250523/202505230141.4YBHhrPI-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/20250523/202505230141.4YBHhrPI-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/202505230141.4YBHhrPI-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/x86/kernel/signal_32.c:32:
   arch/x86/include/asm/sighandling.h: In function 'prevent_single_step_upon_eretu':
>> arch/x86/include/asm/sighandling.h:44:21: error: 'struct pt_regs' has no member named 'fred_ss'
      44 |                 regs->fred_ss.swevent = 0;
         |                     ^~


vim +44 arch/x86/include/asm/sighandling.h

    26	
    27	/*
    28	 * To prevent infinite SIGTRAP handler loop if TF is used without an external
    29	 * debugger, clear the software event flag in the augmented SS, ensuring no
    30	 * single-step trap is pending upon ERETU completion.
    31	 *
    32	 * Note, this function should be called in sigreturn() before the original state
    33	 * is restored to make sure the TF is read from the entry frame.
    34	 */
    35	static __always_inline void prevent_single_step_upon_eretu(struct pt_regs *regs)
    36	{
    37		/*
    38		 * If the trap flag (TF) is set, i.e., the sigreturn() SYSCALL instruction
    39		 * is being single-stepped, do not clear the software event flag in the
    40		 * augmented SS, thus a debugger won't skip over the following instruction.
    41		 */
    42		if (IS_ENABLED(CONFIG_X86_FRED) && cpu_feature_enabled(X86_FEATURE_FRED) &&
    43		    !(regs->flags & X86_EFLAGS_TF))
  > 44			regs->fred_ss.swevent = 0;
    45	}
    46	

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