From 59d85b39c97725fb4084fe1131b80b2c9a16e531 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Lesimple?= <speed47_github@speed47.net>
Date: Sun, 15 Apr 2018 20:55:01 +0200
Subject: [PATCH] feat: detect RSB filling capability in the kernel

---
 spectre-meltdown-checker.sh | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index 858b02d..ca25d5c 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -2293,6 +2293,22 @@ check_variant2_linux()
 			fi
 		fi
 
+		if is_skylake_cpu; then
+			_info_nol "  * Kernel supports RSB filling: "
+			if ! which "${opt_arch_prefix}strings" >/dev/null 2>&1; then
+				pstatus yellow UNKNOWN "missing '${opt_arch_prefix}strings' tool, please install it, usually it's in the binutils package"
+			elif [ -z "$kernel" ]; then
+				pstatus yellow UNKNOWN "kernel image missing"
+			else
+				rsb_filling=$("${opt_arch_prefix}strings" "$kernel" | grep -w 'Filling RSB on context switch')
+				if [ -n "$rsb_filling" ]; then
+					pstatus green YES
+				else
+					pstatus yellow NO
+				fi
+			fi
+		fi
+
 	elif [ "$sys_interface_available" = 0 ]; then
 		# we have no sysfs but were asked to use it only!
 		msg="/sys vulnerability interface use forced, but it's not available!"