From d838270e2516db11084bed4e294017eb7b646a75 Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Thu, 4 Jun 2015 18:55:15 +0200 Subject: [PATCH] x86/mm, asm-generic: Add ioremap_wt() for creating Write-Through mappings Add ioremap_wt() for creating Write-Through mappings on x86. It follows the same model as ioremap_wc() for multi-arch support. Define ARCH_HAS_IOREMAP_WT in the x86 version of io.h to indicate that ioremap_wt() is implemented on x86. Also update the PAT documentation file to cover ioremap_wt(). Signed-off-by: Toshi Kani Signed-off-by: Borislav Petkov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Elliott@hp.com Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Luis R. Rodriguez Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: arnd@arndb.de Cc: hch@lst.de Cc: hmh@hmh.eng.br Cc: jgross@suse.com Cc: konrad.wilk@oracle.com Cc: linux-mm Cc: linux-nvdimm@lists.01.org Cc: stefan.bader@canonical.com Cc: yigal@plexistor.com Link: http://lkml.kernel.org/r/1433436928-31903-8-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- Documentation/x86/pat.txt | 4 +++- arch/x86/include/asm/io.h | 2 ++ arch/x86/mm/ioremap.c | 21 +++++++++++++++++++++ include/asm-generic/io.h | 9 +++++++++ include/asm-generic/iomap.h | 4 ++++ 5 files changed, 39 insertions(+), 1 deletion(-) diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt index 521bd8adc3b8..db0de6cfc351 100644 --- a/Documentation/x86/pat.txt +++ b/Documentation/x86/pat.txt @@ -12,7 +12,7 @@ virtual addresses. PAT allows for different types of memory attributes. The most commonly used ones that will be supported at this time are Write-back, Uncached, -Write-combined and Uncached Minus. +Write-combined, Write-through and Uncached Minus. PAT APIs @@ -40,6 +40,8 @@ ioremap_nocache | -- | UC- | UC- | | | | | ioremap_wc | -- | -- | WC | | | | | +ioremap_wt | -- | -- | WT | + | | | | set_memory_uc | UC- | -- | -- | set_memory_wb | | | | | | | | diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index a94463063b46..83ec9b1d77cc 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -35,6 +35,7 @@ */ #define ARCH_HAS_IOREMAP_WC +#define ARCH_HAS_IOREMAP_WT #include #include @@ -320,6 +321,7 @@ extern void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr); extern int ioremap_change_attr(unsigned long vaddr, unsigned long size, enum page_cache_mode pcm); extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size); +extern void __iomem *ioremap_wt(resource_size_t offset, unsigned long size); extern bool is_early_ioremap_ptep(pte_t *ptep); diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index cc0f17c5ad9f..07cd46a8f30a 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -172,6 +172,10 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, prot = __pgprot(pgprot_val(prot) | cachemode2protval(_PAGE_CACHE_MODE_WC)); break; + case _PAGE_CACHE_MODE_WT: + prot = __pgprot(pgprot_val(prot) | + cachemode2protval(_PAGE_CACHE_MODE_WT)); + break; case _PAGE_CACHE_MODE_WB: break; } @@ -297,6 +301,23 @@ void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size) } EXPORT_SYMBOL(ioremap_wc); +/** + * ioremap_wt - map memory into CPU space write through + * @phys_addr: bus address of the memory + * @size: size of the resource to map + * + * This version of ioremap ensures that the memory is marked write through. + * Write through stores data into memory while keeping the cache up-to-date. + * + * Must be freed with iounmap. + */ +void __iomem *ioremap_wt(resource_size_t phys_addr, unsigned long size) +{ + return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WT, + __builtin_return_address(0)); +} +EXPORT_SYMBOL(ioremap_wt); + void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) { return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB, diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index 90ccba7f9f9a..f56094cfdeff 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -785,8 +785,17 @@ static inline void __iomem *ioremap_wc(phys_addr_t offset, size_t size) } #endif +#ifndef ioremap_wt +#define ioremap_wt ioremap_wt +static inline void __iomem *ioremap_wt(phys_addr_t offset, size_t size) +{ + return ioremap_nocache(offset, size); +} +#endif + #ifndef iounmap #define iounmap iounmap + static inline void iounmap(void __iomem *addr) { } diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h index 1b41011643a5..d8f8622fa044 100644 --- a/include/asm-generic/iomap.h +++ b/include/asm-generic/iomap.h @@ -66,6 +66,10 @@ extern void ioport_unmap(void __iomem *); #define ioremap_wc ioremap_nocache #endif +#ifndef ARCH_HAS_IOREMAP_WT +#define ioremap_wt ioremap_nocache +#endif + #ifdef CONFIG_PCI /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */ struct pci_dev; -- 2.20.1