Hi,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[1] https://elixir.bootlin.com/linux/v6.5/source/include/asm-generic/fb.h#L19 [2] https://elixir.bootlin.com/linux/v6.5/source/arch/mips/include/asm/fb.h#L11 [3] https://elixir.bootlin.com/linux/v6.5/source/arch/powerpc/include/asm/fb.h#L12 [4] https://elixir.bootlin.com/linux/v6.5/source/drivers/video/fbdev/core/fbmem.c#L1299
-- 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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