Use reserve_memtype and free_memtype interfaces in set_memory_uc/set_memory_wb interfaces to avoid aliasing. Usage model of set_memory_uc and set_memory_wb is for RAM memory and users will first call set_memory_uc and call set_memory_wb after use to reset the attribute. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Index: linux-2.6-x86.git/arch/x86/mm/pageattr.c =================================================================== --- linux-2.6-x86.git.orig/arch/x86/mm/pageattr.c 2008-03-18 02:16:06.000000000 -0700 +++ linux-2.6-x86.git/arch/x86/mm/pageattr.c 2008-03-18 09:20:30.000000000 -0700 @@ -19,6 +19,7 @@ #include #include #include +#include /* * The current flushing context - we pass it instead of 5 arguments: @@ -771,18 +772,34 @@ return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask); } -int set_memory_uc(unsigned long addr, int numpages) +int _set_memory_uc(unsigned long addr, int numpages) { return change_page_attr_set(addr, numpages, __pgprot(_PAGE_CACHE_UC)); } + +int set_memory_uc(unsigned long addr, int numpages) +{ + if (reserve_memtype(addr, addr + numpages * PAGE_SIZE, + _PAGE_CACHE_UC, NULL)) + return -EINVAL; + + return _set_memory_uc(addr, numpages); +} EXPORT_SYMBOL(set_memory_uc); -int set_memory_wb(unsigned long addr, int numpages) +int _set_memory_wb(unsigned long addr, int numpages) { return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_CACHE_MASK)); } + +int set_memory_wb(unsigned long addr, int numpages) +{ + free_memtype(addr, addr + numpages * PAGE_SIZE); + + return _set_memory_wb(addr, numpages); +} EXPORT_SYMBOL(set_memory_wb); int set_memory_x(unsigned long addr, int numpages) Index: linux-2.6-x86.git/arch/x86/mm/ioremap.c =================================================================== --- linux-2.6-x86.git.orig/arch/x86/mm/ioremap.c 2008-03-18 03:19:44.000000000 -0700 +++ linux-2.6-x86.git/arch/x86/mm/ioremap.c 2008-03-18 09:20:25.000000000 -0700 @@ -96,10 +96,10 @@ switch (prot_val) { case _PAGE_CACHE_UC: default: - err = set_memory_uc(vaddr, nrpages); + err = _set_memory_uc(vaddr, nrpages); break; case _PAGE_CACHE_WB: - err = set_memory_wb(vaddr, nrpages); + err = _set_memory_wb(vaddr, nrpages); break; } Index: linux-2.6-x86.git/include/asm-x86/cacheflush.h =================================================================== --- linux-2.6-x86.git.orig/include/asm-x86/cacheflush.h 2008-03-18 02:16:06.000000000 -0700 +++ linux-2.6-x86.git/include/asm-x86/cacheflush.h 2008-03-18 09:20:30.000000000 -0700 @@ -34,6 +34,8 @@ int set_pages_ro(struct page *page, int numpages); int set_pages_rw(struct page *page, int numpages); +int _set_memory_uc(unsigned long addr, int numpages); +int _set_memory_wb(unsigned long addr, int numpages); int set_memory_uc(unsigned long addr, int numpages); int set_memory_wb(unsigned long addr, int numpages); int set_memory_x(unsigned long addr, int numpages); -- -- 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/