From 4bb82551e165f887448f6f61055d7bcd90aefa2a Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 13 Aug 2005 14:22:59 -0700 Subject: [PATCH] Fix up mmap of /dev/kmem This leaves the issue of whether we should deprecate the whole thing (or if we should check the whole mmap range, for that matter) open. Just do the minimal fix for now. --- drivers/char/mem.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 42187381506..850a78c9c4b 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -261,7 +261,11 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma) static int mmap_kmem(struct file * file, struct vm_area_struct * vma) { - unsigned long long val; + unsigned long pfn; + + /* Turn a kernel-virtual address into a physical page frame */ + pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; + /* * RED-PEN: on some architectures there is more mapped memory * than available in mem_map which pfn_valid checks @@ -269,10 +273,10 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma) * * RED-PEN: vmalloc is not supported right now. */ - if (!pfn_valid(vma->vm_pgoff)) + if (!pfn_valid(pfn)) return -EIO; - val = (u64)vma->vm_pgoff << PAGE_SHIFT; - vma->vm_pgoff = __pa(val) >> PAGE_SHIFT; + + vma->vm_pgoff = pfn; return mmap_mem(file, vma); } -- 2.20.1