On Wed, 2016-05-25 at 01:33 +0200, Luis R. Rodriguez wrote: > On Wed, Apr 27, 2016 at 09:25:57AM -0600, Toshi Kani wrote: > > > > On x86, ioremap() and remap_pfn_range() fail on conflicting cache > > type of an alias mapping request only if the case is not allowed > > by the rule set in is_new_memtype_allowed(). While this exemption > > is necessary for remap_pfn_range() called for /dev/mem mappings, > > it is not necessary for ioremap(). > > The wording here is a bit unclear. How about:
I will update the change log according to your suggestions. > > Link: https://lkml.org/lkml/2016/4/16/54 > > lkml.org references should be avoided, we have no control over > that domain. Please instead use: > > http://lkml.kernel.org/r/[email protected] Will do. > > > > Signed-off-by: Toshi Kani <[email protected]> > > Cc: Ingo Molnar <[email protected]> > > Cc: Thomas Gleixner <[email protected]> > > Cc: "H. Peter Anvin" <[email protected]> > > Cc: Borislav Petkov <[email protected]> > > Cc: Luis R. Rodriguez <[email protected]> > > Cc: Andy Lutomirski <[email protected]> > > Cc: Dan Williams <[email protected]> > > --- > > arch/x86/mm/ioremap.c | 10 ++++++---- > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > > index 0d8d53d..16c5887 100644 > > --- a/arch/x86/mm/ioremap.c > > +++ b/arch/x86/mm/ioremap.c > > @@ -138,14 +138,16 @@ static void __iomem > > *__ioremap_caller(resource_size_t phys_addr, > > } > > > > if (pcm != new_pcm) { > > - if (!is_new_memtype_allowed(phys_addr, size, pcm, > > new_pcm)) { > > - printk(KERN_ERR > > - "ioremap error for 0x%llx-0x%llx, requested 0x%x, got > > 0x%x\n", > > + retval = is_new_memtype_allowed(phys_addr, size, pcm, > > new_pcm); > > + pr_err( > > + "ioremap %s for 0x%llx-0x%llx, requested 0x%x, got > > 0x%x\n", > > + retval ? "warning" : "error", > > (unsigned long long)phys_addr, > > (unsigned long long)(phys_addr + > > size), > > pcm, new_pcm); > > This doesn't really make it humanly consumable, a pcm_to_str may help, > such use already exists but not generalized see pat_get_cache_mode(). OK, I will add a pcm_to_str. > > > > + if (!retval) > > goto err_free_memtype; > > - } > > + > > pcm = new_pcm; > > } > > In the future we may be able to proactively hunt for these invalid uses > semantically but to do so we need first a demo driver with all known > possible bugs we can think of. Right. Thanks, -Toshi
