From 18e780b4e6ab89a3a10f46d151971863562c1c91 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Tue, 7 Jun 2022 20:50:25 +0800 Subject: [PATCH] mm: ioremap: Add ioremap/iounmap_allowed() Add special hook for architecture to verify addr, size or prot when ioremap() or iounmap(), which will make the generic ioremap more useful. ioremap_allowed() return a bool, - true means continue to remap - false means skip remap and return directly iounmap_allowed() return a bool, - true means continue to vunmap - false code means skip vunmap and return directly Meanwhile, only vunmap the address when it is in vmalloc area as the generic ioremap only returns vmalloc addresses. Acked-by: Andrew Morton Signed-off-by: Kefeng Wang Reviewed-by: Christoph Hellwig Reviewed-by: Baoquan He Link: https://lore.kernel.org/r/20220607125027.44946-5-wangkefeng.wang@huawei.com Signed-off-by: Will Deacon --- include/asm-generic/io.h | 26 ++++++++++++++++++++++++++ mm/ioremap.c | 11 ++++++++++- 2 files changed, 36 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index b76379628a02..db5b890eaff7 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -964,6 +964,32 @@ static inline void iounmap(volatile void __iomem *addr) #elif defined(CONFIG_GENERIC_IOREMAP) #include +/* + * Arch code can implement the following two hooks when using GENERIC_IOREMAP + * ioremap_allowed() return a bool, + * - true means continue to remap + * - false means skip remap and return directly + * iounmap_allowed() return a bool, + * - true means continue to vunmap + * - false means skip vunmap and return directly + */ +#ifndef ioremap_allowed +#define ioremap_allowed ioremap_allowed +static inline bool ioremap_allowed(phys_addr_t phys_addr, size_t size, + unsigned long prot) +{ + return true; +} +#endif + +#ifndef iounmap_allowed +#define iounmap_allowed iounmap_allowed +static inline bool iounmap_allowed(void *addr) +{ + return true; +} +#endif + void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long prot); void iounmap(volatile void __iomem *addr); diff --git a/mm/ioremap.c b/mm/ioremap.c index e1d008e8f87f..8652426282cc 100644 --- a/mm/ioremap.c +++ b/mm/ioremap.c @@ -28,6 +28,9 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, phys_addr -= offset; size = PAGE_ALIGN(size + offset); + if (!ioremap_allowed(phys_addr, size, prot)) + return NULL; + area = get_vm_area_caller(size, VM_IOREMAP, __builtin_return_address(0)); if (!area) @@ -47,6 +50,12 @@ EXPORT_SYMBOL(ioremap_prot); void iounmap(volatile void __iomem *addr) { - vunmap((void *)((unsigned long)addr & PAGE_MASK)); + void *vaddr = (void *)((unsigned long)addr & PAGE_MASK); + + if (!iounmap_allowed(vaddr)) + return; + + if (is_vmalloc_addr(vaddr)) + vunmap(vaddr); } EXPORT_SYMBOL(iounmap);