On Wed, May 15, 2013 at 06:06:26PM +0900, HATAYAMA Daisuke wrote: > This patch introduces mmap_vmcore(). > > Don't permit writable nor executable mapping even with mprotect() > because this mmap() is aimed at reading crash dump memory. > Non-writable mapping is also requirement of remap_pfn_range() when > mapping linear pages on non-consecutive physical pages; see > is_cow_mapping(). > > Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by > remap_vmalloc_range_pertial at the same time for a single > vma. do_munmap() can correctly clean partially remapped vma with two > functions in abnormal case. See zap_pte_range(), vm_normal_page() and > their comments for details. > > On x86-32 PAE kernels, mmap() supports at most 16TB memory only. This > limitation comes from the fact that the third argument of > remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long. > > Signed-off-by: HATAYAMA Daisuke <[email protected]> > ---
This one looks fine to me assuming vm folks like remap_vmalloc_range_partial(). Acked-by: Vivek Goyal <[email protected]> Thanks Vivek > > fs/proc/vmcore.c | 86 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 86 insertions(+), 0 deletions(-) > > diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c > index 7f2041c..2c72487 100644 > --- a/fs/proc/vmcore.c > +++ b/fs/proc/vmcore.c > @@ -20,6 +20,7 @@ > #include <linux/init.h> > #include <linux/crash_dump.h> > #include <linux/list.h> > +#include <linux/vmalloc.h> > #include <asm/uaccess.h> > #include <asm/io.h> > #include "internal.h" > @@ -200,9 +201,94 @@ static ssize_t read_vmcore(struct file *file, char > __user *buffer, > return acc; > } > > +static int mmap_vmcore(struct file *file, struct vm_area_struct *vma) > +{ > + size_t size = vma->vm_end - vma->vm_start; > + u64 start, end, len, tsz; > + struct vmcore *m; > + > + start = (u64)vma->vm_pgoff << PAGE_SHIFT; > + end = start + size; > + > + if (size > vmcore_size || end > vmcore_size) > + return -EINVAL; > + > + if (vma->vm_flags & (VM_WRITE | VM_EXEC)) > + return -EPERM; > + > + vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC); > + vma->vm_flags |= VM_MIXEDMAP; > + > + len = 0; > + > + if (start < elfcorebuf_sz) { > + u64 pfn; > + > + tsz = elfcorebuf_sz - start; > + if (size < tsz) > + tsz = size; > + pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT; > + if (remap_pfn_range(vma, vma->vm_start, pfn, tsz, > + vma->vm_page_prot)) > + return -EAGAIN; > + size -= tsz; > + start += tsz; > + len += tsz; > + > + if (size == 0) > + return 0; > + } > + > + if (start < elfcorebuf_sz + elfnotes_sz) { > + void *kaddr; > + > + tsz = elfcorebuf_sz + elfnotes_sz - start; > + if (size < tsz) > + tsz = size; > + kaddr = elfnotes_buf + start - elfcorebuf_sz; > + if (remap_vmalloc_range_partial(vma, vma->vm_start + len, > + kaddr, tsz)) { > + do_munmap(vma->vm_mm, vma->vm_start, len); > + return -EAGAIN; > + } > + size -= tsz; > + start += tsz; > + len += tsz; > + > + if (size == 0) > + return 0; > + } > + > + list_for_each_entry(m, &vmcore_list, list) { > + if (start < m->offset + m->size) { > + u64 paddr = 0; > + > + tsz = m->offset + m->size - start; > + if (size < tsz) > + tsz = size; > + paddr = m->paddr + start - m->offset; > + if (remap_pfn_range(vma, vma->vm_start + len, > + paddr >> PAGE_SHIFT, tsz, > + vma->vm_page_prot)) { > + do_munmap(vma->vm_mm, vma->vm_start, len); > + return -EAGAIN; > + } > + size -= tsz; > + start += tsz; > + len += tsz; > + > + if (size == 0) > + return 0; > + } > + } > + > + return 0; > +} > + > static const struct file_operations proc_vmcore_operations = { > .read = read_vmcore, > .llseek = default_llseek, > + .mmap = mmap_vmcore, > }; > > static struct vmcore* __init get_new_element(void) -- 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/
