[PATCH v11 5/9] x86/cet/ibt: Update arch_prctl functions for Indirect Branch Tracking

[Yu-cheng Yu]

From: "H.J. Lu" <hjl.to...@gmail.com>

Update ARCH_X86_CET_STATUS and ARCH_X86_CET_DISABLE for Indirect Branch
Tracking.

Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng...@intel.com>
---
 arch/x86/kernel/cet_prctl.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cet_prctl.c b/arch/x86/kernel/cet_prctl.c
index cc49eef08ab0..2cd089e1542c 100644
--- a/arch/x86/kernel/cet_prctl.c
+++ b/arch/x86/kernel/cet_prctl.c
@@ -22,6 +22,9 @@ static int copy_status_to_user(struct cet_status *cet, u64 
arg2)
                buf[2] = (u64)cet->shstk_size;
        }
 
+       if (cet->ibt_enabled)
+               buf[0] |= GNU_PROPERTY_X86_FEATURE_1_IBT;
+
        return copy_to_user((u64 __user *)arg2, buf, sizeof(buf));
 }
 
@@ -72,7 +75,8 @@ int prctl_cet(int option, u64 arg2)
        if (option == ARCH_X86_CET_STATUS)
                return copy_status_to_user(cet, arg2);
 
-       if (!static_cpu_has(X86_FEATURE_SHSTK))
+       if (!static_cpu_has(X86_FEATURE_SHSTK) &&
+           !static_cpu_has(X86_FEATURE_IBT))
                return -EOPNOTSUPP;
 
        switch (option) {
@@ -83,6 +87,8 @@ int prctl_cet(int option, u64 arg2)
                        return -EINVAL;
                if (arg2 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)
                        cet_disable_free_shstk(current);
+               if (arg2 & GNU_PROPERTY_X86_FEATURE_1_IBT)
+                       cet_disable_ibt();
                return 0;
 
        case ARCH_X86_CET_LOCK:
-- 
2.21.0