The kernel now has the main shadow stack functionality to support
applications. Wire in the WRSS and shadow stack enable/disable functions
into the existing shadow stack API skeleton.

Tested-by: Pengfei Xu <redacted>
Tested-by: John Allen <john.allen@amd.com>
Reviewed-by: Kees Cook <redacted>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>

---
v4:
 - Remove "CET" references

v2:
 - Split from other patches
---
 arch/x86/kernel/shstk.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
index 009cb3fa0ae5..2faf9b45ac72 100644
--- a/arch/x86/kernel/shstk.c
+++ b/arch/x86/kernel/shstk.c

@@ -464,9 +464,17 @@ long shstk_prctl(struct task_struct *task, int option, unsigned long features)
 		return -EINVAL;
 
 	if (option == ARCH_SHSTK_DISABLE) {
+		if (features & ARCH_SHSTK_WRSS)
+			return wrss_control(false);
+		if (features & ARCH_SHSTK_SHSTK)
+			return shstk_disable();
 		return -EINVAL;
 	}
 
 	/* Handle ARCH_SHSTK_ENABLE */
+	if (features & ARCH_SHSTK_SHSTK)
+		return shstk_setup();
+	if (features & ARCH_SHSTK_WRSS)
+		return wrss_control(true);
 	return -EINVAL;
 }

-- 
2.17.1