From: Toshi Kani <toshi.k...@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.k...@hp.com> Reviewed-by: Thomas Gleixner <t...@linutronix.de> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andy Lutomirski <l...@amacapital.net> Cc: a...@arndb.de Cc: elli...@hp.com Cc: h...@lst.de Cc: h...@hmh.eng.br Cc: H. Peter Anvin <h...@zytor.com> Cc: Ingo Molnar <mi...@redhat.com> Cc: jgr...@suse.com Cc: konrad.w...@oracle.com Cc: linux-mm <linux...@kvack.org> Cc: linux-nvd...@lists.01.org Cc: Luis R. Rodriguez <mcg...@suse.com> Cc: stefan.ba...@canonical.com Cc: x86-ml <x...@kernel.org> Cc: yi...@plexistor.com Link: http://lkml.kernel.org/r/1433187393-22688-4-git-send-email-toshi.k...@hp.com Signed-off-by: Borislav Petkov <b...@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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
