Commit 1a4e8795 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/mm/pat: Revert 'Adjust default caching mode translation tables' 



Toshi explains:

"No, the default values need to be set to the fallback types,
 i.e. minimal supported mode.  For WC and WT, UC is the fallback type.

 When PAT is disabled, pat_init() does update the tables below to
 enable WT per the default BIOS setup.  However, when PAT is enabled,
 but CPU has PAT -errata, WT falls back to UC per the default values."

Revert: ca1fec58 'x86/mm/pat: Adjust default caching mode translation tables'
Requested-by: default avatarToshi Kani <toshi.kani@hp.com>
Cc: Jan Beulich <jbeulich@suse.de>
Link: http://lkml.kernel.org/r/1437577776.3214.252.camel@hp.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent c0c3322e

arch/x86/mm/init.c

+3 −3
Original line number Diff line number Diff line
@@ -43,18 +43,18 @@ uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = { 
	[_PAGE_CACHE_MODE_WC      ]	= 0         | _PAGE_PCD,

	[_PAGE_CACHE_MODE_UC_MINUS]	= 0         | _PAGE_PCD,

	[_PAGE_CACHE_MODE_UC      ]	= _PAGE_PWT | _PAGE_PCD,

	[_PAGE_CACHE_MODE_WT      ]	= _PAGE_PWT | 0,

	[_PAGE_CACHE_MODE_WT      ]	= 0         | _PAGE_PCD,

	[_PAGE_CACHE_MODE_WP      ]	= 0         | _PAGE_PCD,

};

EXPORT_SYMBOL(__cachemode2pte_tbl);



uint8_t __pte2cachemode_tbl[8] = {

	[__pte2cm_idx( 0        | 0         | 0        )] = _PAGE_CACHE_MODE_WB,

	[__pte2cm_idx(_PAGE_PWT | 0         | 0        )] = _PAGE_CACHE_MODE_WT,

	[__pte2cm_idx(_PAGE_PWT | 0         | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,

	[__pte2cm_idx( 0        | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC_MINUS,

	[__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0        )] = _PAGE_CACHE_MODE_UC,

	[__pte2cm_idx( 0        | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,

	[__pte2cm_idx(_PAGE_PWT | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_WT,

	[__pte2cm_idx(_PAGE_PWT | 0         | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,

	[__pte2cm_idx(0         | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,

	[__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,

};

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