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From:   Yu-cheng Yu <yu-cheng.yu@intel.com>
To:     x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
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Cc:     Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v11 5/9] x86/cet/ibt: Update arch_prctl functions for Indirect Branch Tracking
Date:   Mon, 24 Aug 2020 17:26:40 -0700
Message-Id: <20200825002645.3658-6-yu-cheng.yu@intel.com>
In-Reply-To: <20200825002645.3658-1-yu-cheng.yu@intel.com>
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From: "H.J. Lu" <hjl.tools@gmail.com>

Update ARCH_X86_CET_STATUS and ARCH_X86_CET_DISABLE for Indirect Branch
Tracking.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@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