Messages in this thread | | | Date | Tue, 18 Oct 2022 13:33:55 -0500 | Subject | Re: [PATCH net] net: fman: Use physical address for userspace interfaces | From | Andrew Davis <> |
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On 10/18/22 12:37 PM, Sean Anderson wrote: > Hi Andrew, > > On 10/18/22 1:22 PM, Andrew Lunn wrote: >> On Mon, Oct 17, 2022 at 12:28:06PM -0400, Sean Anderson wrote: >>> For whatever reason, the address of the MAC is exposed to userspace in >>> several places. We need to use the physical address for this purpose to >>> avoid leaking information about the kernel's memory layout, and to keep >>> backwards compatibility. >> >> How does this keep backwards compatibility? Whatever is in user space >> using this virtual address expects a virtual address. If it now gets a >> physical address it will probably do the wrong thing. Unless there is >> a one to one mapping, and you are exposing virtual addresses anyway. >> >> If you are going to break backwards compatibility Maybe it would be >> better to return 0xdeadbeef? Or 0? >> >> Andrew >> > > The fixed commit was added in v6.1-rc1 and switched from physical to > virtual. So this is effectively a partial revert to the previous > behavior (but keeping the other changes). See [1] for discussion. > > --Sean > > [1] https://lore.kernel.org/netdev/20220902215737.981341-1-sean.anderson@seco.com/T/#md5c6b66bc229c09062d205352a7d127c02b8d262
I see it asked in that thread, but not answered. Why are you exposing "physical" addresses to userspace? There should be no reason for that.
Andrew
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