From 20c5ea4fc131dc45c2639653b5b7aeeb2d4d0d1e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 4 Mar 2016 10:05:39 +0100 Subject: [PATCH 1/4] ARM: reintroduce ioremap_cached() for creating cached I/O mappings The original ARM-only ioremap flavor 'ioremap_cached' has been renamed to 'ioremap_cache' to align with other architectures, and subsequently abused in generic code to map things like firmware tables in memory. For that reason, there is currently an effort underway to deprecate ioremap_cache, whose semantics are poorly defined, and which is typed with an __iomem annotation that is inappropriate for mappings of ordinary memory. However, original users of ioremap_cached() used it in a context where the I/O connotation is appropriate, and replacing those instances with memremap() does not make sense. So let's revive ioremap_cached(), so that we can change back those original users before we drop ioremap_cache entirely in favor of memremap. Cc: Russell King Acked-by: Dan Williams Signed-off-by: Ard Biesheuvel --- arch/arm/include/asm/io.h | 6 ++++++ arch/arm/mm/ioremap.c | 4 ++++ arch/arm/mm/nommu.c | 4 ++++ 3 files changed, 14 insertions(+) diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index 485982084fe9..fb94de290edd 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -395,6 +395,12 @@ void __iomem *ioremap(resource_size_t res_cookie, size_t size); void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size); #define ioremap_cache ioremap_cache +/* + * Do not use ioremap_cached in new code. Provided for the benefit of + * the pxa2xx-flash MTD driver only. + */ +void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size); + void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size); #define ioremap_wc ioremap_wc #define ioremap_wt ioremap_wc diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index 66a978d05958..d5350f6af089 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -380,11 +380,15 @@ void __iomem *ioremap(resource_size_t res_cookie, size_t size) EXPORT_SYMBOL(ioremap); void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size) + __alias(ioremap_cached); + +void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size) { return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED, __builtin_return_address(0)); } EXPORT_SYMBOL(ioremap_cache); +EXPORT_SYMBOL(ioremap_cached); void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) { diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index 1dd10936d68d..f24967e8ff7f 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -367,11 +367,15 @@ void __iomem *ioremap(resource_size_t res_cookie, size_t size) EXPORT_SYMBOL(ioremap); void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size) + __alias(ioremap_cached); + +void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size) { return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED, __builtin_return_address(0)); } EXPORT_SYMBOL(ioremap_cache); +EXPORT_SYMBOL(ioremap_cached); void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) { From 7769aea2a27db8f12859dcecce37a3da44ab588b Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 25 Feb 2016 08:57:52 +0100 Subject: [PATCH 2/4] mtd: pxa2xx-flash: switch back from memremap to ioremap_cached This reverts commit 06968a54790d ("mtd: pxa2xx-flash: switch from ioremap_cache to memremap"), since NOR with memory semantics in array mode and RAM are not necessarily the same thing, and architectures may implement ioremap_cached() and memremap() with different memory attributes. For this reason, ioremap_cached() has been brought back from the dead on the ARM side, so switch this driver back to using it instead of memremap(). Cc: David Woodhouse Acked-by: Brian Norris Acked-by: Dan Williams Signed-off-by: Ard Biesheuvel --- drivers/mtd/maps/pxa2xx-flash.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/maps/pxa2xx-flash.c b/drivers/mtd/maps/pxa2xx-flash.c index 7497090e9900..2cde28ed95c9 100644 --- a/drivers/mtd/maps/pxa2xx-flash.c +++ b/drivers/mtd/maps/pxa2xx-flash.c @@ -71,8 +71,8 @@ static int pxa2xx_flash_probe(struct platform_device *pdev) info->map.name); return -ENOMEM; } - info->map.cached = memremap(info->map.phys, info->map.size, - MEMREMAP_WB); + info->map.cached = + ioremap_cached(info->map.phys, info->map.size); if (!info->map.cached) printk(KERN_WARNING "Failed to ioremap cached %s\n", info->map.name); @@ -111,7 +111,7 @@ static int pxa2xx_flash_remove(struct platform_device *dev) map_destroy(info->mtd); iounmap(info->map.virt); if (info->map.cached) - memunmap(info->map.cached); + iounmap(info->map.cached); kfree(info); return 0; } From c269cba35b061181bc23c470809c00e8f71e535a Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 22 Feb 2016 15:02:07 +0100 Subject: [PATCH 3/4] memremap: add arch specific hook for MEMREMAP_WB mappings Currently, the memremap code serves MEMREMAP_WB mappings directly from the kernel direct mapping, unless the region is in high memory, in which case it falls back to using ioremap_cache(). However, the semantics of ioremap_cache() are not unambiguously defined, and on ARM, it will actually result in a mapping type that differs from the attributes used for the linear mapping, and for this reason, the ioremap_cache() call fails if the region is part of the memory managed by the kernel. So instead, implement an optional hook 'arch_memremap_wb' whose default implementation calls ioremap_cache() as before, but which can be overridden by the architecture to do what is appropriate for it. Acked-by: Dan Williams Signed-off-by: Ard Biesheuvel --- kernel/memremap.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/memremap.c b/kernel/memremap.c index a6d382312e6f..017532193fb1 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -27,6 +27,13 @@ __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size) } #endif +#ifndef arch_memremap_wb +static void *arch_memremap_wb(resource_size_t offset, unsigned long size) +{ + return (__force void *)ioremap_cache(offset, size); +} +#endif + static void *try_ram_remap(resource_size_t offset, size_t size) { unsigned long pfn = PHYS_PFN(offset); @@ -34,7 +41,7 @@ static void *try_ram_remap(resource_size_t offset, size_t size) /* In the simple case just return the existing linear address */ if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn))) return __va(offset); - return NULL; /* fallback to ioremap_cache */ + return NULL; /* fallback to arch_memremap_wb */ } /** @@ -90,7 +97,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags) if (is_ram == REGION_INTERSECTS) addr = try_ram_remap(offset, size); if (!addr) - addr = ioremap_cache(offset, size); + addr = arch_memremap_wb(offset, size); } /* From 9ab9e4fce45379cb6a7dbf87cf8f8e6ba01853c2 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 22 Feb 2016 15:02:08 +0100 Subject: [PATCH 4/4] ARM: memremap: implement arch_memremap_wb() The generic memremap() falls back to using ioremap_cache() to create MEMREMAP_WB mappings if the requested region is not already covered by the linear mapping, unless the architecture provides an implementation of arch_memremap_wb(). Since ioremap_cache() is not appropriate on ARM to map memory with the same attributes used for the linear mapping, implement arch_memremap_wb() which does exactly that. Also, relax the WARN() check to allow MT_MEMORY_RW mappings of pfn_valid() pages. Cc: Russell King Acked-by: Dan Williams Signed-off-by: Ard Biesheuvel --- arch/arm/include/asm/io.h | 6 ++++++ arch/arm/mm/ioremap.c | 12 ++++++++++-- arch/arm/mm/nommu.c | 5 +++++ 3 files changed, 21 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index fb94de290edd..781ef5fe235d 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -392,6 +392,9 @@ void __iomem *ioremap(resource_size_t res_cookie, size_t size); #define ioremap ioremap #define ioremap_nocache ioremap +/* + * Do not use ioremap_cache for mapping memory. Use memremap instead. + */ void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size); #define ioremap_cache ioremap_cache @@ -408,6 +411,9 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size); void iounmap(volatile void __iomem *iomem_cookie); #define iounmap iounmap +void *arch_memremap_wb(phys_addr_t phys_addr, size_t size); +#define arch_memremap_wb arch_memremap_wb + /* * io{read,write}{16,32}be() macros */ diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index d5350f6af089..ff0eed23ddf1 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -297,9 +297,10 @@ static void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, } /* - * Don't allow RAM to be mapped - this causes problems with ARMv6+ + * Don't allow RAM to be mapped with mismatched attributes - this + * causes problems with ARMv6+ */ - if (WARN_ON(pfn_valid(pfn))) + if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW)) return NULL; area = get_vm_area_caller(size, VM_IOREMAP, caller); @@ -418,6 +419,13 @@ __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached) __builtin_return_address(0)); } +void *arch_memremap_wb(phys_addr_t phys_addr, size_t size) +{ + return (__force void *)arch_ioremap_caller(phys_addr, size, + MT_MEMORY_RW, + __builtin_return_address(0)); +} + void __iounmap(volatile void __iomem *io_addr) { void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index f24967e8ff7f..ca6d8e8ca1f8 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -384,6 +384,11 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) } EXPORT_SYMBOL(ioremap_wc); +void *arch_memremap_wb(phys_addr_t phys_addr, size_t size) +{ + return (void *)phys_addr; +} + void __iounmap(volatile void __iomem *addr) { }