On Wed, Feb 21, 2024 at 07:22:21PM +0000, Edgecombe, Rick P wrote: > On Wed, 2024-02-21 at 14:06 -0500, dalias@xxxxxxxx wrote: > > It's fine to turn RDSSP into an actual emulated read of the SSP, or > > at > > least an emulated load of zero so that uninitialized data is not left > > in the target register. > We can't intercept RDSSP, but it becomes a NOP by default. (disclaimer > x86-only knowledge). For arm64 we have a separate control GCSCRE0_EL1.nTR for access to GCSPR_EL0 (our SSP equivalent) we can use. > > I have not looked at all the instructions that become #UD but I > > suspect they all have reasonable trivial ways to implement a > > "disabled" version of them that userspace can act upon reasonably. > This would have to be thought through functionally and performance > wise. I'm not opposed if can come up with a fully fleshed out plan. How > serious are you in pursuing musl support, if we had something like > this? Same here, we have to be careful since it's defining ABI in a way that we don't normally provide ABI but if there's a clear case for doing it then...
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