Re: 2.4 vm, program load, page faulting, ...

[wind@cocodriloo.com]

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On Mon, Mar 17, 2003 at 08:06:36PM +0100, wind-lkml@cocodriloo.com wrote:
> On Mon, Mar 17, 2003 at 07:57:49PM +0100, Marc-Christian Petersen wrote:
> > On Monday 17 March 2003 18:38, wind-lkml@cocodriloo.com wrote:
> > 
> > Hi Wind,
> > 
> > > > I wonder if this could be done by walking and faulting
> > > > all pages at fs/binfmt_elf.c::elf_map just after do_mmap...
> > > > will try it just now :)
> > >
> > > OK, this is not tested, since I'm compiling it now... feel free
> > > to correct :)
> > 
> > mm/mmap.c:
> > 
> > unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, unsigned 
> > long len,
> >         unsigned long prot, unsigned long flags, unsigned long pgoff)
> > {
> > 
> > your "do_mmap_pgoff" calls 7 arguments. Obviously it cannot compile 8-)
> > 
> 
> My first patch, I'm just becoming intimate with printk ;)

OK, so I took a different approach, and just called handle_mm_fault just
like if there had been user-level accesses to the file.

Applied on 2.5.63-uml1 and booted debian woody with it.

Can any of you try it on a real machine? (I dont have a test machine :(

Greets, Antonio.


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--- orig/fs/binfmt_elf.c	Mon Mar 17 20:30:17 2003
+++ work/fs/binfmt_elf.c	Mon Mar 17 20:30:29 2003
@@ -259,12 +259,26 @@ create_elf_tables(struct linux_binprm *b
 static inline unsigned long
 elf_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
 {
-	unsigned long map_addr;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	unsigned long map_addr, n;
 
 	down_write(&current->mm->mmap_sem);
 	map_addr = do_mmap(filep, ELF_PAGESTART(addr),
 			   eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr), prot, type,
 			   eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr));
+
+
+	addr = ELF_PAGESTART(addr);
+	mm = current->mm;
+	vma = find_vma(mm, addr);
+	if(!vma)
+		goto out;
+
+	for(n = 0; n < eppnt->p_filesz; n+=PAGE_SIZE)
+		handle_mm_fault(mm, vma, addr + n, 0);
+
+out:
 	up_write(&current->mm->mmap_sem);
 	return(map_addr);
 }