Add a transaction attribute indicating that a memory access is being
done from user-mode (unprivileged). This corresponds to an equivalent
signal in ARM AMBA buses.
Backports commit 0995bf8cd91b81ec9c1078e37b808794080dc5c0 from qemu
Honour the NS bit in ARM page tables:
* when adding entries to the TLB, include the Secure/NonSecure
transaction attribute
* set the NS bit in the PAR when doing ATS operations
Note that we don't yet correctly use the NSTable bit to
cause the page table walk itself to use the right attributes.
Backports commit 8bf5b6a9c1911d2c8473385fc0cebfaaeef42dbc from qem
Define an API so that devices can register MemoryRegionOps whose read
and write callback functions are passed an arbitrary pointer to some
transaction attributes and can return a success-or-failure status code.
This will allow us to model devices which:
* behave differently for ARM Secure/NonSecure memory accesses
* behave differently for privileged/unprivileged accesses
* may return a transaction failure (causing a guest exception)
for erroneous accesses
This patch defines the new API and plumbs the attributes parameter through
to the memory.c public level functions io_mem_read() and io_mem_write(),
where it is currently dummied out.
The success/failure response indication is also propagated out to
io_mem_read() and io_mem_write(), which retain the old-style
boolean true-for-error return.
Backports commit cc05c43ad942165ecc6ffd39e41991bee43af044 from qemu
