* Bug#894995: rdma-core: Please add support for new architecture "riscv64" (RISC-V 64 bits little-endian) [not found] <152297424964.29286.16311629290309565149.reportbug@reva.itsari.org> @ 2018-04-19 12:00 ` Benjamin Drung 2018-04-20 15:31 ` Jason Gunthorpe 0 siblings, 1 reply; 2+ messages in thread From: Benjamin Drung @ 2018-04-19 12:00 UTC (permalink / raw) To: Manuel A. Fernandez Montecelo, 894995, List Linux RDMA Mailing Hi, Thanks for reporting this bug. Am Freitag, den 06.04.2018, 02:24 +0200 schrieb Manuel A. Fernandez Montecelo: > Source: rdma-core > Version: 17.1-1 > Severity: normal > Tags: patch > User: debian-riscv@lists.debian.org > Usertags: riscv64 > > Hello, > > The current version of this package doesn't build for the riscv64 > port. > > First it fails to be considered to build (due to missing valgrind) > and, when > fixing that problem, FBTFS, because of missing files (see at bottom). I'll apply that part of the patch. > I applied the same fix as for many other arches, which is to add the > arch to the > list of NO_COHERENT_DMA_ARCHS in debian/rules. > > I am not sure if support could be added at a later date, but for the > time being, > seems to be the best way to get it working -- I don't know enough > details of the > architecture or the assembly language to get the necessary > incantations in > place. RISC-V has a FENCE instruction and the A extension (which is part of the G instruction set) provides atomic memory operations. So the architecture should provide coherent DMA support. To enable support, util/udma_barrier.h needs to be adjusted. I am including linux-rdma@vger.kernel.org in the loop for help. ^ permalink raw reply [flat|nested] 2+ messages in thread
* Bug#894995: rdma-core: Please add support for new architecture "riscv64" (RISC-V 64 bits little-endian) 2018-04-19 12:00 ` Bug#894995: rdma-core: Please add support for new architecture "riscv64" (RISC-V 64 bits little-endian) Benjamin Drung @ 2018-04-20 15:31 ` Jason Gunthorpe 0 siblings, 0 replies; 2+ messages in thread From: Jason Gunthorpe @ 2018-04-20 15:31 UTC (permalink / raw) To: Benjamin Drung Cc: Manuel A. Fernandez Montecelo, 894995, List Linux RDMA Mailing On Thu, Apr 19, 2018 at 02:00:18PM +0200, Benjamin Drung wrote: > > I applied the same fix as for many other arches, which is to add the > > arch to the > > list of NO_COHERENT_DMA_ARCHS in debian/rules. > > > > I am not sure if support could be added at a later date, but for the > > time being, > > seems to be the best way to get it working -- I don't know enough > > details of the > > architecture or the assembly language to get the necessary > > incantations in > > place. > > RISC-V has a FENCE instruction and the A extension (which is part of > the G instruction set) provides atomic memory operations. So the > architecture should provide coherent DMA support. To enable support, > util/udma_barrier.h needs to be adjusted. I am including > linux-rdma@vger.kernel.org in the loop for help. You can't tell from the instruction set if a chip is DMA coherent or not. It depends how the cache's are designed, and if they have a 'snoop controller' or otherwise. Generally if *any* DMA coherent implementations exist then we should add the fences, otherwise better to just not compile the drivers that have no chance of working. Jason ^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-04-19 12:00 ` Bug#894995: rdma-core: Please add support for new architecture "riscv64" (RISC-V 64 bits little-endian) Benjamin Drung
2018-04-20 15:31 ` Jason Gunthorpe
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