https://github.com/torvalds/linux
Revision 116d753308cf032159c7b7aa87c9605bb5354784 authored by John David Anglin on 02 June 2019, 23:12:40 UTC, committed by Helge Deller on 06 June 2019, 12:12:22 UTC
Most I/O in the kernel is done using the kernel offset mapping. However, there is one API that uses aliased kernel address ranges: > The final category of APIs is for I/O to deliberately aliased address > ranges inside the kernel. Such aliases are set up by use of the > vmap/vmalloc API. Since kernel I/O goes via physical pages, the I/O > subsystem assumes that the user mapping and kernel offset mapping are > the only aliases. This isn't true for vmap aliases, so anything in > the kernel trying to do I/O to vmap areas must manually manage > coherency. It must do this by flushing the vmap range before doing > I/O and invalidating it after the I/O returns. For this reason, we should use the hardware lpa instruction to load the physical address of kernel virtual addresses in the driver code. I believe we only use the vmap/vmalloc API with old PA 1.x processors which don't have a sba, so we don't hit this problem. Tested on c3750, c8000 and rp3440. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
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Tip revision: 116d753308cf032159c7b7aa87c9605bb5354784 authored by John David Anglin on 02 June 2019, 23:12:40 UTC
parisc: Use lpa instruction to load physical addresses in driver code
parisc: Use lpa instruction to load physical addresses in driver code
Tip revision: 116d753
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| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 71 bytes |
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| COPYING | -rw-r--r-- | 423 bytes |
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| MAINTAINERS | -rw-r--r-- | 499.1 KB |
| Makefile | -rw-r--r-- | 58.8 KB |
| README | -rw-r--r-- | 727 bytes |
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