[compiler-rt] [FMV][compiler-rt] Fix cpu features initialization. (PR #95149)

[Alexandros Lamprineas via llvm-commits]

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@@ -52,23 +45,20 @@ static void __init_cpu_features_constructor(unsigned long hwcap,
     setCPUFeature(FEAT_FCMA);
   if (hwcap & HWCAP_SB)
     setCPUFeature(FEAT_SB);
-  if (hwcap & HWCAP_SSBS)
+  if (hwcap & HWCAP_SSBS) {
+    setCPUFeature(FEAT_SSBS);
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labrinea wrote:

>From the Arm Architecture Reference Manual on the documentation of `ID_AA64PFR1_EL1.SSBS`:
"FEAT_SSBS2 implements the functionality identified by the value 0b0010".

As far as I understand HWCAP_SSBS is set based on that value. Here is one resource I found https://www.kernel.org/doc/html/next/arm64/elf_hwcaps.html
> HWCAP_SSBS
> Functionality implied by ID_AA64PFR1_EL1.SSBS == 0b0010.



https://github.com/llvm/llvm-project/pull/95149