On Wed, Mar 25, 2015 at 9:04 AM, Christoph Hellwig <hch(a)lst.de> wrote:
Here is another version of the same trivial pmem driver, because two
obviously aren't enough.
Welcome to the party! :-)
The first patch is the same pmem driver
that Ross posted a short time ago, just modified to use platform_devices
to find the persistant memory region instead of hardconding it in the
Kconfig. This allows to keep pmem.c separate from any discovery mechanism,
but still allow auto-discovery.
This is mostly ok and does not collide too much with the upcoming ACPI
mechanism for this stuff. I do worry that the new
"memmap=nn[KMG]!ss[KMG]" kernel command line option will only be
relevant for at most one kernel cycle given the imminent publication
of the spec that unblocks our release.
Our planned solution to the "legacy pmem" problem is to have a
userspace utility craft a list of address ranges in the form that ACPI
expects and attach that to a platform device (one time setup). It
only requires that the memory be marked reserved, not necessarily
The other two patches are a heavily rewritten version of the code
Intel gave to various storage vendors to discover the type 12 (and earlier
type 6) nvdimms, which I massaged into a form that is hopefully suitable
I'd prefer E820_PMEM over E820_PROTECTED_KERN, I don't know why I
chose that name initially, but to each his own bike shed.