Boris, could you check that this series also fixes the /dev/mem problem you were seeing?
-- We have a new debugging check on x86 that has caught a number of long-standing bugs. However, there is a _bit_ of collateral damage with things that call __pa(high_memory). We are now checking that any addresses passed to __pa() are *valid* and can be dereferenced. "high_memory", however, is not valid. It marks the start of highmem, and isn't itself a valid pointer. But, those users are really just asking "is this vaddr mapped"? So, give them a helper that does that, plus is also kind to our new debugging check. Signed-off-by: Dave Hansen <[email protected]> --- linux-2.6.git-dave/arch/x86/mm/pat.c | 11 ++++++----- linux-2.6.git-dave/drivers/char/mem.c | 4 ++-- linux-2.6.git-dave/drivers/mtd/mtdchar.c | 2 +- linux-2.6.git-dave/include/linux/mm.h | 13 +++++++++++++ 4 files changed, 22 insertions(+), 8 deletions(-) diff -puN drivers/char/mem.c~clean-up-highmem-checks drivers/char/mem.c --- linux-2.6.git/drivers/char/mem.c~clean-up-highmem-checks 2013-02-08 08:42:37.291222110 -0800 +++ linux-2.6.git-dave/drivers/char/mem.c 2013-02-08 12:27:27.837477867 -0800 @@ -51,7 +51,7 @@ static inline unsigned long size_inside_ #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE static inline int valid_phys_addr_range(phys_addr_t addr, size_t count) { - return addr + count <= __pa(high_memory); + return !phys_addr_is_highmem(addr + count); } static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) @@ -250,7 +250,7 @@ static int uncached_access(struct file * */ if (file->f_flags & O_DSYNC) return 1; - return addr >= __pa(high_memory); + return phys_addr_is_highmem(addr); #endif } #endif diff -puN include/linux/mm.h~clean-up-highmem-checks include/linux/mm.h --- linux-2.6.git/include/linux/mm.h~clean-up-highmem-checks 2013-02-08 08:42:37.295222148 -0800 +++ linux-2.6.git-dave/include/linux/mm.h 2013-02-08 09:01:49.758254468 -0800 @@ -1771,5 +1771,18 @@ static inline unsigned int debug_guardpa static inline bool page_is_guard(struct page *page) { return false; } #endif /* CONFIG_DEBUG_PAGEALLOC */ +static inline phys_addr_t last_lowmem_phys_addr(void) +{ + /* + * 'high_memory' is not a pointer that can be dereferenced, so + * avoid calling __pa() on it directly. + */ + return __pa(high_memory - 1); +} +static inline bool phys_addr_is_highmem(phys_addr_t addr) +{ + return addr > last_lowmem_paddr(); +} + #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ diff -puN arch/arm/mm/mmap.c~clean-up-highmem-checks arch/arm/mm/mmap.c diff -puN arch/arm/mach-u300/core.c~clean-up-highmem-checks arch/arm/mach-u300/core.c diff -puN arch/mips/loongson/common/mem.c~clean-up-highmem-checks arch/mips/loongson/common/mem.c diff -puN arch/mips/mm/cache.c~clean-up-highmem-checks arch/mips/mm/cache.c diff -puN arch/sh/mm/mmap.c~clean-up-highmem-checks arch/sh/mm/mmap.c diff -puN arch/x86/mm/pat.c~clean-up-highmem-checks arch/x86/mm/pat.c --- linux-2.6.git/arch/x86/mm/pat.c~clean-up-highmem-checks 2013-02-08 08:48:29.486594289 -0800 +++ linux-2.6.git-dave/arch/x86/mm/pat.c 2013-02-08 09:03:32.435231850 -0800 @@ -542,7 +542,7 @@ int phys_mem_access_prot_allowed(struct boot_cpu_has(X86_FEATURE_K6_MTRR) || boot_cpu_has(X86_FEATURE_CYRIX_ARR) || boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) && - (pfn << PAGE_SHIFT) >= __pa(high_memory)) { + phys_addr_is_highmem(pfn << PAGE_SHIFT)) { flags = _PAGE_CACHE_UC; } #endif @@ -560,12 +560,13 @@ int kernel_map_sync_memtype(u64 base, un { unsigned long id_sz; - if (base > __pa(high_memory-1)) + if (phys_addr_is_highmem(base)) return 0; - id_sz = (__pa(high_memory-1) <= base + size) ? - __pa(high_memory) - base : - size; + if (phys_addr_is_highmem(base + size - 1)) + id_sz = last_lowmem_phys_addr() - base + 1; + else + id_sz = size; if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) { printk(KERN_INFO "%s:%d ioremap_change_attr failed %s " diff -puN drivers/mtd/mtdchar.c~clean-up-highmem-checks drivers/mtd/mtdchar.c --- linux-2.6.git/drivers/mtd/mtdchar.c~clean-up-highmem-checks 2013-02-08 08:59:26.632884014 -0800 +++ linux-2.6.git-dave/drivers/mtd/mtdchar.c 2013-02-08 09:50:56.410398581 -0800 @@ -1189,7 +1189,7 @@ static int mtdchar_mmap(struct file *fil vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; #ifdef pgprot_noncached - if (file->f_flags & O_DSYNC || off >= __pa(high_memory)) + if (file->f_flags & O_DSYNC || phys_addr_is_highmem(off)) vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); #endif if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT, diff -puN arch/um/kernel/physmem.c~clean-up-highmem-checks arch/um/kernel/physmem.c _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
