================
@@ -106,9 +111,14 @@ static void emitSCSEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB,
CSI, [&](CalleeSavedInfo &CSR) { return CSR.getReg() == RAReg; }))
return;
+ const RISCVInstrInfo *TII = STI.getInstrInfo();
+ if (STI.hasFeature(RISCV::FeatureStdExtZicfiss)) {
----------------
samitolvanen wrote:
> > Do we need an enable other than just the feature being in -march? The
> > shadow stack pointer has to be set up when the application starts. Is this
> > done by the kernel?
> > My concern is that if your -mcpu supports Zicfiss, but the kernel doesn't,
> > this will generate code that doesn't work.
>
> oh, that's good point...let me check how other target do
If the kernel doesn't support Zicfiss, it presumably also hasn't enabled the
extension for U-mode. Therefore, my understanding is that the application
loader can simply skip shadow stack setup for the program, including the
`prctl` (which would fail with `-EINVAL`), and since the Zicfiss (Zimop)
instructions are no-ops when the extension is disabled, the program would run
normally, just without shadow stacks. Does this sound correct?
https://github.com/llvm/llvm-project/pull/68075
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
