linux-kernel - [PATCH 4/5] x86/pti: warn for unknown pti boot options

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Date:   Mon, 16 Jul 2018 12:03:39 +0800
From:   Jiang Biao <jiang.biao2@....com.cn>
To:     tglx@...utronix.de, mingo@...hat.com
Cc:     dave.hansen@...ux.intel.com, luto@...nel.org, hpa@...or.com,
        x86@...nel.org, albcamus@...il.com, linux-kernel@...r.kernel.org,
        zhong.weidong@....com.cn, jiang.biao2@....com.cn
Subject: [PATCH 4/5] x86/pti: warn for unknown pti boot options

When using unknown pti boot options other than on/off/auto, we
select auto silently, which is sometimes confusing. Add warning for
unknown pti boot options like we do in
spectre_v2_select_mitigation().

Signed-off-by: Jiang Biao <jiang.biao2@....com.cn>
---
 arch/x86/mm/pti.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index a76b2cc..a368656 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -92,14 +92,14 @@ void __init pti_check_boottime_disable(void)
 			pti_mode = PTI_FORCE_OFF;
 			pti_print_if_insecure("disabled on command line.");
 			return;
-		}
-		if (ret == 2 && !strncmp(arg, "on", 2)) {
+		} else if (ret == 2 && !strncmp(arg, "on", 2)) {
 			pti_mode = PTI_FORCE_ON;
 			pti_print_if_secure("force enabled on command line.");
 			goto enable;
-		}
-		if (ret == 4 && !strncmp(arg, "auto", 4)) {
-			pti_mode = PTI_AUTO;
+		} else if (ret == 4 && !strncmp(arg, "auto", 4)) {
+			goto autosel;
+		} else {
+			pr_err("unknown option (%s). Switching to AUTO select\n", arg);
 			goto autosel;
 		}
 	}
-- 
2.7.4