[PATCH v22 5/8] 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>
Reviewed-by: Kees Cook <keesc...@chromium.org>
---
 arch/x86/kernel/cet_prctl.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/cet_prctl.c b/arch/x86/kernel/cet_prctl.c
index 0030c63a08c0..4df1eac41965 100644
--- a/arch/x86/kernel/cet_prctl.c
+++ b/arch/x86/kernel/cet_prctl.c
@@ -22,6 +22,9 @@ static int cet_copy_status_to_user(struct cet_status *cet, 
u64 __user *ubuf)
                buf[2] = cet->shstk_size;
        }
 
+       if (cet->ibt_enabled)
+               buf[0] |= GNU_PROPERTY_X86_FEATURE_1_IBT;
+
        return copy_to_user(ubuf, buf, sizeof(buf));
 }
 
@@ -46,6 +49,8 @@ int prctl_cet(int option, u64 arg2)
                        return -EINVAL;
                if (arg2 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)
                        cet_disable_shstk();
+               if (arg2 & GNU_PROPERTY_X86_FEATURE_1_IBT)
+                       cet_disable_ibt();
                return 0;
 
        case ARCH_X86_CET_LOCK:
-- 
2.21.0