Date: Tue, 9 May 2017 11:05:32 +0000 (UTC) From: Michal Meloun <mmel@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r318021 - in head/sys/arm: arm include Message-ID: <201705091105.v49B5WAp097952@repo.freebsd.org>
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Author: mmel Date: Tue May 9 11:05:32 2017 New Revision: 318021 URL: https://svnweb.freebsd.org/changeset/base/318021 Log: Introduce pmap_remap_vm_attr(), 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 Modified: head/sys/arm/arm/pmap-v6.c head/sys/arm/include/pmap-v6.h Modified: head/sys/arm/arm/pmap-v6.c ============================================================================== --- head/sys/arm/arm/pmap-v6.c Tue May 9 10:42:23 2017 (r318020) +++ head/sys/arm/arm/pmap-v6.c Tue May 9 11:05:32 2017 (r318021) @@ -498,6 +498,25 @@ pmap_set_tex(void) } /* + * 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 * meets same constrain due to PT2MAP being placed just under KERNBASE. Modified: head/sys/arm/include/pmap-v6.h ============================================================================== --- head/sys/arm/include/pmap-v6.h Tue May 9 10:42:23 2017 (r318020) +++ head/sys/arm/include/pmap-v6.h Tue May 9 11:05:32 2017 (r318021) @@ -188,6 +188,7 @@ vm_offset_t pmap_preboot_reserve_pages(u 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_ */
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