[PATCH v26 5/9] x86/cet/ibt: Update arch_prctl functions for Indirect Branch Tracking

Yu-cheng Yu
2021-04-27T20:47:58Z

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>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
v24:
- Update for function name changes introduced from splitting shadow stack and ibt.

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 3bb9f32ca70d..ab05597545c5 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)
shstk_disable();
+ if (arg2 & GNU_PROPERTY_X86_FEATURE_1_IBT)
+ ibt_disable();
return 0;

case ARCH_X86_CET_LOCK:
--
2.21.0