This size was used to break up DMA transactions so that a single
transaction would not cross a page boundary. This was because on Alpha,
there was an actual page table which translated between PCI and DMA
address spaces. On all currently implemented systems, the mapping is
simply to add a scalar offset, so it's not possible for a legal region
of memory to be contiguous in one space but not in the other.
Additionally, if it *was* possible for there to be a mismatch, it was
only coincidence that Alpha used a page table which had the same sized
pages as it normally used. There is no requirement that there even would
be fixed sized pages in the first place.
To avoid this artificial dependency between the IDE controller and the
ISA, this change simply changes the chunk size for DMA accesses to 4K.
That's the page size at least on x86 and probably other architectures,
and will be a pretty close approximation of the previous behavior.
It's possible that even having this chunking in the first place is
unnecessary and functionally useless, but there are some checks which
happen between chunks, and changing how big they are would change the
frequency of those checks. For instance, the controller/disk may not
notice in the same amount of time if a DMA was cancelled somehow.
Change-Id: I1ec840d1f158c3faa31ba0184458b69bf654c252
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34178
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
isa_traits.hh used to have much more in it, but now it only has
PageShift, PageBytes, and (for now) the guest endianness. These values
should only be retrieved from the System class generally speaking, so
only the system class should include arch/isa_traits.hh.
Some gpu compute related files need PageBytes or PageShift. Even though
those files don't advertise their ISA dependence, they are tied to x86.
In those files, they can include arch/x86/isa_traits.hh.
The only other file which legitimately needs arch/isa_traits.hh is the
decoder cache since it uses PageBytes to size an array.
Change-Id: I12686368715623e3140a68a7027c136bd52567b1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33203
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
GCC 7.2 is much stricter than previous GCC versions. The following changes
are needed:
* There is now a warning if there is an implicit fallthrough between two
case statments. C++17 adds the [[fallthrough]]; declaration. However,
to support non C++17 standards (i.e., C++11), we use M5_FALLTHROUGH.
M5_FALLTHROUGH checks for [[fallthrough]] compliant C++17 compiler and
if that doesn't exist, it defaults to nothing (no older compilers
generate warnings).
* The above resulted in a couple of bugs that were found. This is noted
in the review request on gerrit.
* throw() for dynamic exception specification is deprecated
* There were a couple of new uninitialized variable warnings
* Can no longer perform bitwise operations on a bool.
* Must now include <functional> for std::function
* Compiler bug for void* lambda. Changed to auto as work around. See
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82878
Change-Id: I5d4c782a4e133fa4cdb119e35d9aff68c6e2958e
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/5802
Reviewed-by: Gabe Black <gabeblack@google.com>
Add a case for the ATA command ATAPI_IDENTIFY_DEVICE.
This avoids the panic: Unsupported ATA command when booting a recent Linux
kernel. This was tested on 4.8.13.
Change-Id: Ib297a2c02da0730d8698c59801254dd0f5ee9f7f
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/2863
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
We want to extend the stats of objects hierarchically and thus it is necessary
to register the statistics of the base-class(es), as well. For now, these are
empty, but generic stats will be added there.
Patch originally provided by Akash Bagdia at ARM Ltd.
