What is the function of arch/x86/purgatory/purgatory.c?

[Larry Finger]

While checking the rtlwifi family of drivers using Sparse, I got the following 
warnings:

  CHECK   arch/x86/purgatory/purgatory.c
arch/x86/purgatory/purgatory.c:21:15: warning: symbol 'backup_dest' was not 
declared. Should it be static?
arch/x86/purgatory/purgatory.c:22:15: warning: symbol 'backup_src' was not 
declared. Should it be static?
arch/x86/purgatory/purgatory.c:23:15: warning: symbol 'backup_sz' was not 
declared. Should it be static?
arch/x86/purgatory/purgatory.c:25:4: warning: symbol 'sha256_digest' was not 
declared. Should it be static?
arch/x86/purgatory/purgatory.c:27:19: warning: symbol 'sha_regions' was not 
declared. Should it be static?
arch/x86/purgatory/purgatory.c:42:5: warning: symbol 'verify_sha256_digest' was 
not declared. Should it be static?
arch/x86/purgatory/purgatory.c:61:6: warning: symbol 'purgatory' was not 
declared. Should it be static?

Upon examination of the routine, I can see that if purgatory() should be static, 
then none of the code here will ever be accessed by any part of the kernel. Is 
there some bit of magic that is above my understanding, or is this a useless bit 
of code that has been forgotten and should be removed?

If the former, then I think there should be declarations so that the clueless 
like me are not confused.

Thanks,

Larry