Messages in this thread | | | Date | Thu, 05 Mar 2015 09:42:20 +0100 | From | Juergen Gross <> | Subject | Re: [PATCH] x86/mm/pat: Initialize __cachemode2pte_tbl[] and __pte2cachemode_tbl[] in a bit more readable fashion |
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On 03/05/2015 09:21 AM, Ingo Molnar wrote: > > ( So this patch is not directly related to gbpages, but while reading > arch/x86/mm/init.c I could not resist ... ) > > =======================> > > The initialization of these two arrays is a bit difficult to follow: > restructure it optically so that a 2D structure shows which bit in > the PTE is set and which not. > > Also improve on comments a bit. > > No code or data changed: > > # arch/x86/mm/init.o: > > text data bss dec hex filename > 4585 424 29776 34785 87e1 init.o.before > 4585 424 29776 34785 87e1 init.o.after > > md5: > a82e11ff58bcfd0af3a94662a701f65d init.o.before.asm > a82e11ff58bcfd0af3a94662a701f65d init.o.after.asm > > Cc: Andy Lutomirski <luto@amacapital.net> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Cc: Jan Beulich <JBeulich@suse.com> > Cc: Juergen Gross <jgross@suse.com> > Cc: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Luis R. Rodriguez <mcgrof@suse.com> > Cc: Toshi Kani <toshi.kani@hp.com> > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
> --- > arch/x86/mm/init.c | 40 ++++++++++++++++++++++------------------ > 1 file changed, 22 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index 6dc85d51cd98..4469563f8c3b 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -29,29 +29,33 @@ > > /* > * Tables translating between page_cache_type_t and pte encoding. > - * Minimal supported modes are defined statically, modified if more supported > - * cache modes are available. > - * Index into __cachemode2pte_tbl is the cachemode. > - * Index into __pte2cachemode_tbl are the caching attribute bits of the pte > - * (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2. > + * > + * Minimal supported modes are defined statically, they are modified > + * during bootup if more supported cache modes are available. > + * > + * Index into __cachemode2pte_tbl[] is the cachemode. > + * > + * Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte > + * (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2. > */ > uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = { > - [_PAGE_CACHE_MODE_WB] = 0, > - [_PAGE_CACHE_MODE_WC] = _PAGE_PWT, > - [_PAGE_CACHE_MODE_UC_MINUS] = _PAGE_PCD, > - [_PAGE_CACHE_MODE_UC] = _PAGE_PCD | _PAGE_PWT, > - [_PAGE_CACHE_MODE_WT] = _PAGE_PCD, > - [_PAGE_CACHE_MODE_WP] = _PAGE_PCD, > + [_PAGE_CACHE_MODE_WB ] = 0 | 0 , > + [_PAGE_CACHE_MODE_WC ] = _PAGE_PWT | 0 , > + [_PAGE_CACHE_MODE_UC_MINUS] = 0 | _PAGE_PCD, > + [_PAGE_CACHE_MODE_UC ] = _PAGE_PWT | _PAGE_PCD, > + [_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)] = _PAGE_CACHE_MODE_WB, > - [__pte2cm_idx(_PAGE_PWT)] = _PAGE_CACHE_MODE_WC, > - [__pte2cm_idx(_PAGE_PCD)] = _PAGE_CACHE_MODE_UC_MINUS, > - [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD)] = _PAGE_CACHE_MODE_UC, > - [__pte2cm_idx(_PAGE_PAT)] = _PAGE_CACHE_MODE_WB, > - [__pte2cm_idx(_PAGE_PWT | _PAGE_PAT)] = _PAGE_CACHE_MODE_WC, > - [__pte2cm_idx(_PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS, > + [__pte2cm_idx( 0 | 0 | 0 )] = _PAGE_CACHE_MODE_WB, > + [__pte2cm_idx(_PAGE_PWT | 0 | 0 )] = _PAGE_CACHE_MODE_WC, > + [__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(0 | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS, > [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC, > }; > EXPORT_SYMBOL(__pte2cachemode_tbl); > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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