Messages in this thread Patch in this message | | | From | Borislav Petkov <> | Subject | [PATCH 06/20] x86/mm: Teach is_new_memtype_allowed() about Write-Through type | Date | Thu, 4 Jun 2015 18:55:14 +0200 |
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From: Toshi Kani <toshi.kani@hp.com>
__ioremap_caller() calls reserve_memtype() and the passed down @new_pcm contains the actual page cache type it reserved in the success case.
is_new_memtype_allowed() verifies if converting to the new page cache type is allowed when @pcm (the requested type) is different from @new_pcm.
When WT is requested, the caller expects that writes are ordered and uncached. Therefore, enhance is_new_memtype_allowed() to disallow the following cases:
- If the request is WT, mapping type cannot be WB - If the request is WT, mapping type cannot be WC
Signed-off-by: Toshi Kani <toshi.kani@hp.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: arnd@arndb.de Cc: Elliott@hp.com Cc: hch@lst.de Cc: hmh@hmh.eng.br Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: jgross@suse.com Cc: konrad.wilk@oracle.com Cc: linux-mm <linux-mm@kvack.org> Cc: linux-nvdimm@lists.01.org Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: stefan.bader@canonical.com Cc: x86-ml <x86@kernel.org> Cc: yigal@plexistor.com Link: http://lkml.kernel.org/r/1433187393-22688-4-git-send-email-toshi.kani@hp.com Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/include/asm/pgtable.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index fe57e7a98839..2562e303405b 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -398,11 +398,17 @@ static inline int is_new_memtype_allowed(u64 paddr, unsigned long size, * requested memtype: * - request is uncached, return cannot be write-back * - request is write-combine, return cannot be write-back + * - request is write-through, return cannot be write-back + * - request is write-through, return cannot be write-combine */ if ((pcm == _PAGE_CACHE_MODE_UC_MINUS && new_pcm == _PAGE_CACHE_MODE_WB) || (pcm == _PAGE_CACHE_MODE_WC && - new_pcm == _PAGE_CACHE_MODE_WB)) { + new_pcm == _PAGE_CACHE_MODE_WB) || + (pcm == _PAGE_CACHE_MODE_WT && + new_pcm == _PAGE_CACHE_MODE_WB) || + (pcm == _PAGE_CACHE_MODE_WT && + new_pcm == _PAGE_CACHE_MODE_WC)) { return 0; } -- 2.3.5
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