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x86/mm/pat: Emulate PAT when it is disabled

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In the case when PAT is disabled on the command line with
"nopat" or when virtualization doesn't support PAT (correctly) -
see

  9d34cfdf47 ("x86: Don't rely on VMWare emulating PAT MSR correctly").

we emulate it using the PWT and PCD cache attribute bits. Get
rid of boot_pat_state while at it.

Based on a conglomerate patch from Toshi Kani.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov
2015-06-04 18:55:10 +02:00
committed by Ingo Molnar
parent 9dac629094
commit 9cd25aac1f
4 changed files with 60 additions and 34 deletions
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6
arch/x86/mm/init.c
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@@ -40,7 +40,7 @@
*/
uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
[_PAGE_CACHE_MODE_WB ] = 0 | 0 ,
[_PAGE_CACHE_MODE_WC ] = _PAGE_PWT | 0 ,
[_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 ] = 0 | _PAGE_PCD,
@@ -50,11 +50,11 @@ 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_WC,
[__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_WC,
[__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,
};