arch/openrisc/kernel/signal.c:50 restore_fp_state() warn: maybe return -EFAULT instead of the bytes remaining?

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

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: linux-kernel@vger.kernel.org
TO: Stafford Horne <shorne@gmail.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   59b723cd2adbac2a34fc8e12c74ae26ae45bf230
commit: 4dc70e1aadfadf968676d983587c6f5d455aba85 openrisc: Move FPU state out of pt_regs
date:   7 months ago
:::::: branch date: 18 hours ago
:::::: commit date: 7 months ago
config: openrisc-randconfig-r072-20241104 (https://download.01.org/0day-ci/archive/20241105/202411050108.7hvptsS6-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.1.0

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>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202411050108.7hvptsS6-lkp@intel.com/

smatch warnings:
arch/openrisc/kernel/signal.c:50 restore_fp_state() warn: maybe return -EFAULT instead of the bytes remaining?
arch/openrisc/kernel/signal.c:67 save_fp_state() warn: maybe return -EFAULT instead of the bytes remaining?

vim +50 arch/openrisc/kernel/signal.c

1c4de499e6134e Stafford Horne 2023-08-20  39  
1c4de499e6134e Stafford Horne 2023-08-20  40  asmlinkage int do_work_pending(struct pt_regs *regs, unsigned int thread_flags,
1c4de499e6134e Stafford Horne 2023-08-20  41  			       int syscall);
1c4de499e6134e Stafford Horne 2023-08-20  42  
4dc70e1aadfadf Stafford Horne 2024-03-30  43  #ifdef CONFIG_FPU
4dc70e1aadfadf Stafford Horne 2024-03-30  44  static long restore_fp_state(struct sigcontext __user *sc)
4dc70e1aadfadf Stafford Horne 2024-03-30  45  {
4dc70e1aadfadf Stafford Horne 2024-03-30  46  	long err;
4dc70e1aadfadf Stafford Horne 2024-03-30  47  
4dc70e1aadfadf Stafford Horne 2024-03-30  48  	err = __copy_from_user(&current->thread.fpcsr, &sc->fpcsr, sizeof(unsigned long));
4dc70e1aadfadf Stafford Horne 2024-03-30  49  	if (unlikely(err))
4dc70e1aadfadf Stafford Horne 2024-03-30 @50  		return err;
4dc70e1aadfadf Stafford Horne 2024-03-30  51  
4dc70e1aadfadf Stafford Horne 2024-03-30  52  	/* Restore the FPU state */
4dc70e1aadfadf Stafford Horne 2024-03-30  53  	restore_fpu(current);
4dc70e1aadfadf Stafford Horne 2024-03-30  54  
4dc70e1aadfadf Stafford Horne 2024-03-30  55  	return 0;
4dc70e1aadfadf Stafford Horne 2024-03-30  56  }
4dc70e1aadfadf Stafford Horne 2024-03-30  57  
4dc70e1aadfadf Stafford Horne 2024-03-30  58  static long save_fp_state(struct sigcontext __user *sc)
4dc70e1aadfadf Stafford Horne 2024-03-30  59  {
4dc70e1aadfadf Stafford Horne 2024-03-30  60  	long err;
4dc70e1aadfadf Stafford Horne 2024-03-30  61  
4dc70e1aadfadf Stafford Horne 2024-03-30  62  	/* Sync the user FPU state so we can copy to sigcontext */
4dc70e1aadfadf Stafford Horne 2024-03-30  63  	save_fpu(current);
4dc70e1aadfadf Stafford Horne 2024-03-30  64  
4dc70e1aadfadf Stafford Horne 2024-03-30  65  	err = __copy_to_user(&sc->fpcsr, &current->thread.fpcsr, sizeof(unsigned long));
4dc70e1aadfadf Stafford Horne 2024-03-30  66  
4dc70e1aadfadf Stafford Horne 2024-03-30 @67  	return err;
4dc70e1aadfadf Stafford Horne 2024-03-30  68  }
4dc70e1aadfadf Stafford Horne 2024-03-30  69  #else
4dc70e1aadfadf Stafford Horne 2024-03-30  70  #define save_fp_state(sc) (0)
4dc70e1aadfadf Stafford Horne 2024-03-30  71  #define restore_fp_state(sc) (0)
4dc70e1aadfadf Stafford Horne 2024-03-30  72  #endif
4dc70e1aadfadf Stafford Horne 2024-03-30  73  

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