dma: Drop syscalls #97058
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dma: Drop syscalls #97058
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DMA syscalls as they were implemented were unsafe. Accepting a void* was never acceptable as many things could not be verified about it. Accepting a channel identifier meant that a user mode thread could start/stop any DMA channel which in theory could be owned by any other driver. This shouldn't be possible. Signed-off-by: Tom Burdick <[email protected]>
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kv2019i
approved these changes
Oct 6, 2025
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Shouldn't these go through the deprecation process before being removed? I mean, they seem to be as old as 2018... |
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Marking DNM until deprecation process is done |
API isn't changing, but yes the dropping of syscall is something that likely needs to be considered. It's wrong though as its written so we do need to drop this. |
henrikbrixandersen
approved these changes
Oct 6, 2025
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DMA syscalls as they were implemented were unsafe. Accepting a void* was never acceptable as many things could not be verified about it. Accepting a channel identifier meant that a user mode thread could start/stop any DMA channel which in theory could be owned by any other driver. This shouldn't be possible.
Likely we need to at least rethink this by making the pair (dma device, dma channel) a kobject that can be granted/revoked on at the very least.
Related #96985
RFC for breaking change #97071