On Thu, Nov 28, 2024 at 08:47:28PM +0000, Lorenzo Stoakes wrote:
> Peter - not sure whether it's easy for you to make a simple adjustment to this
> patch or if you want me to just send a v2, but I have to pop an #ifdef CONFIG_MMU
> into the code.
>
> > +static int map_range(struct perf_buffer *rb, struct vm_area_struct *vma)
> > +{
> > + unsigned long nr_pages = vma_pages(vma);
> > + int err = 0;
> > + unsigned long pgoff;
> > +
> > + for (pgoff = 0; pgoff < nr_pages; pgoff++) {
> > + unsigned long va = vma->vm_start + PAGE_SIZE * pgoff;
> > + struct page *page = perf_mmap_to_page(rb, pgoff);
> > +
> > + if (page == NULL) {
> > + err = -EINVAL;
> > + break;
> > + }
> > +
> > + /* Map readonly, perf_mmap_pfn_mkwrite() called on write fault. */
> > + err = remap_pfn_range(vma, va, page_to_pfn(page), PAGE_SIZE,
> > + vm_get_page_prot(vma->vm_flags & ~VM_SHARED));
> > + if (err)
> > + break;
> > + }
> > +
>
> Need a:
>
> #ifdef CONFIG_MMU
> > + /* Clear any partial mappings on error. */
> > + if (err)
> > + zap_page_range_single(vma, vma->vm_start, nr_pages * PAGE_SIZE, NULL);
> #endif
>
> Here to work around the wonders of nommu :)
All good, I'll edit the thing.
