On Thu, 31 Jan 2008 18:16:30 +0200
Pekka Paalanen <[EMAIL PROTECTED]> wrote:
> > > could you please send us a patch for the whole mmiotrace
> > > kernel-side feature, so that we can have a look at the general
> > > structure of this? (and the interaction with change_page_attr(),
> > > etc.) Even if it's not functional (and wont even build/boot) at
> > > the moment. Thanks,
>
> And here's mmiotrace. This works for me (amd64), but not for a test
> user who has 32-bit x86. We have not had the chance to debug it yet.
> The symptom is "everything locked up" after insmodding
> testmmiotrace.ko, targeting the mid-point of his VRAM. And there's
> the "undefined symbol init_mm" problem on 32-bit, but we just put the
> export back in (not included in these patches).
>
> No-one has tried this on SMP. I have a Core 2 Duo laptop where I will
> test this when I get the chance.
+static void print_pte(unsigned long address)
> +{
> + pgd_t *pgd = pgd_offset_k(address);
> + pud_t *pud = pud_offset(pgd, address);
> + pmd_t *pmd = pmd_offset(pud, address);
> + if (pmd_large(*pmd)) {
> + printk(KERN_EMERG MODULE_NAME ": 4MB pages are not "
> + "currently
> supported: %lx\n",
> + address);
> + BUG();
> + }
> + printk(KERN_DEBUG MODULE_NAME ": pte for 0x%lx: 0x%lx
> 0x%lx\n",
> + address,
> + pte_val(*pte_offset_kernel(pmd, address)),
> + pte_val(*pte_offset_kernel(pmd, address)) &
> _PAGE_PRESENT); +}
ok this wants to use some of the page_address() and other helpers from
pageattr.c;
that should be easy to solve during integration
(I can even see a more generic version of this function moving there)
> +/* file_create() callback. Creates relay file in debugfs. */
> +static struct dentry *create_buf_file_handler(const char *filename,
> + struct dentry
> *parent,
> + int mode,
> + struct rchan_buf
> *buf,
> + int *is_global)
> +{
> + struct dentry *buf_file;
> +
> + mmio_fops.read = relay_file_operations.read;
> + mmio_fops.open = relay_file_operations.open;
> + mmio_fops.poll = relay_file_operations.poll;
> + mmio_fops.mmap = relay_file_operations.mmap;
> + mmio_fops.release = relay_file_operations.release;
> + mmio_fops.splice_read = relay_file_operations.splice_read;
can't we do this at compile time?
> +
> +void __iomem *ioremap_cache_trace(unsigned long offset, unsigned
> long size) +{
> + void __iomem *p = ioremap_cache(offset, size);
> + printk(KERN_DEBUG MODULE_NAME ": ioremap_cache(0x%lx, 0x%lx)
> = %p\n",
> + offset,
> size, p);
> + ioremap_trace_core(offset, size, p);
> + return p;
> +}
> +EXPORT_SYMBOL(ioremap_cache_trace);
> +
> +void __iomem *ioremap_nocache_trace(unsigned long offset, unsigned
> long size) +{
> + void __iomem *p = ioremap_nocache(offset, size);
> + printk(KERN_DEBUG MODULE_NAME ": ioremap_nocache(0x%lx,
> 0x%lx) = %p\n",
> + offset,
> size, p);
> + ioremap_trace_core(offset, size, p);
> + return p;
> +}
> +EXPORT_SYMBOL(ioremap_nocache_trace);
I would rather keep the split I think and make the trace call explicit
or.. even nicer, we could go fancy and allow the mmio tracer to "subscribe"
to, say, a PCI bar, and auto-enable tracing when the bar gets ioremap'd
about the isntruction decoding.. would be nice if we can share that with kvm
so that we can debug that stuff once ;-)
other than that I think the code is quite nice already, seems getting this merge
ready isn't going to be an enormous deal in terms of complexity
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