Framebuffer mmap on PowerPC

Thomas Zimmermann tzimmermann at
Fri Sep 1 00:41:35 AEST 2023


there's a per-architecture function called fb_pgprotect() that sets 
VMA's vm_page_prot for mmaped framebuffers. Most architectures use a 
simple implementation based on pgprot_writecomine() [1] or 
pgprot_noncached(). [2]

On PPC this function uses phys_mem_access_prot() and therefore requires 
the mmap call's file struct. [3] Removing the file argument would help 
with simplifying the caller of fb_pgprotect(). [4]

Why is the file even required on PPC?

Is it possible to replace phys_mem_access_prot() with something simpler 
that does not use the file struct?

Best regards


Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
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