From 8b150478aeb1a8edb9015c2f7ac4da637ff65c45 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Fri, 28 Oct 2005 17:46:18 -0700 Subject: [PATCH] ppc: make phys_mem_access_prot() work with pfns instead of addresses Change the phys_mem_access_prot() function to take a pfn instead of an address. This allows mmap64() to work on /dev/mem for addresses above 4G on 32-bit architectures. We start with a pfn in mmap_mem(), so there's no need to convert to an address; in fact, it's actively bad, since the conversion can overflow when the address is above 4G. Similarly fix the ppc32 page_is_ram() function to avoid a conversion to an address by directly comparing to max_pfn. Working with max_pfn instead of high_memory fixes page_is_ram() to give the right answer for highmem pages. Signed-off-by: Roland Dreier Cc: Anton Blanchard Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Paul Mackerras --- arch/ppc/mm/init.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'arch/ppc/mm/init.c') diff --git a/arch/ppc/mm/init.c b/arch/ppc/mm/init.c index db94efd25369..99b48abd3296 100644 --- a/arch/ppc/mm/init.c +++ b/arch/ppc/mm/init.c @@ -637,18 +637,16 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, */ int page_is_ram(unsigned long pfn) { - unsigned long paddr = (pfn << PAGE_SHIFT); - - return paddr < __pa(high_memory); + return pfn < max_pfn; } -pgprot_t phys_mem_access_prot(struct file *file, unsigned long addr, +pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) { if (ppc_md.phys_mem_access_prot) - return ppc_md.phys_mem_access_prot(file, addr, size, vma_prot); + return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot); - if (!page_is_ram(addr >> PAGE_SHIFT)) + if (!page_is_ram(pfn)) vma_prot = __pgprot(pgprot_val(vma_prot) | _PAGE_GUARDED | _PAGE_NO_CACHE); return vma_prot; -- cgit v1.2.3-59-g8ed1b