d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Introduce pmap_remap_vm_attr(),

Browse Source 
it allows to remap one VM memattr class to another.

This function is intent to be used as workaround for various SoC bugs,
mainly access ordering/sequencing related bugs in crossbar fabric.

Inspired by:	https://reviews.freebsd.org/D10218
MFC after:	2 weeks
This commit is contained in:
mmel 2017-05-09 11:05:32 +00:00
parent 12c092ad55
commit f62996a7a4
2 changed files with 20 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
sys/arm/arm/pmap-v6.c
View File

@ -497,6 +497,25 @@ pmap_set_tex(void)
tlb_flush_all_local();
}
/*
* Remap one vm_meattr class to another one. This can be useful as
* workaround for SOC errata, e.g. if devices must be accessed using
* SO memory class.
*/
void
pmap_remap_vm_attr(vm_memattr_t old_attr, vm_memattr_t new_attr)
{
int old_idx, new_idx;
/* Map VM memattrs to indexes to tex_class table. */
old_idx = pte2_attr_tab[(int)old_attr];
new_idx = pte2_attr_tab[(int)new_attr];
/* Replace TEX attribute and apply it. */
tex_class[old_idx] = tex_class[new_idx];
pmap_set_tex();
}
/*
* KERNBASE must be multiple of NPT2_IN_PG * PTE1_SIZE. In other words,
* KERNBASE is mapped by first L2 page table in L2 page table page. It

1
sys/arm/include/pmap-v6.h
View File

@ -188,6 +188,7 @@ vm_offset_t pmap_preboot_reserve_pages(u_int);
vm_offset_t pmap_preboot_get_vpages(u_int);
void pmap_preboot_map_attr(vm_paddr_t, vm_offset_t, vm_size_t, vm_prot_t,
vm_memattr_t);
void pmap_remap_vm_attr(vm_memattr_t old_attr, vm_memattr_t new_attr);
#endif /* _KERNEL */
#endif /* !_MACHINE_PMAP_V6_H_ */