linux-kernel - [PATCH 4.9 39/61] powerpc/pseries: Use the security flags in pseries_setup_rfi

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Date:   Tue,  5 Jun 2018 19:02:00 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.9 39/61] powerpc/pseries: Use the security flags in pseries_setup_rfi_flush()

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michael Ellerman <mpe@...erman.id.au>

commit 2e4a16161fcd324b1f9bf6cb6856529f7eaf0689 upstream.

Now that we have the security flags we can simplify the code in
pseries_setup_rfi_flush() because the security flags have pessimistic
defaults.

Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/powerpc/platforms/pseries/setup.c |   27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -492,30 +492,27 @@ void pseries_setup_rfi_flush(void)
 	bool enable;
 	long rc;
 
-	/* Enable by default */
-	enable = true;
-	types = L1D_FLUSH_FALLBACK;
-
 	rc = plpar_get_cpu_characteristics(&result);
-	if (rc == H_SUCCESS) {
+	if (rc == H_SUCCESS)
 		init_cpu_char_feature_flags(&result);
 
-		if (result.character & H_CPU_CHAR_L1D_FLUSH_TRIG2)
-			types |= L1D_FLUSH_MTTRIG;
-		if (result.character & H_CPU_CHAR_L1D_FLUSH_ORI30)
-			types |= L1D_FLUSH_ORI;
-
-		if ((!(result.behaviour & H_CPU_BEHAV_L1D_FLUSH_PR)) ||
-		    (!(result.behaviour & H_CPU_BEHAV_FAVOUR_SECURITY)))
-			enable = false;
-	}
-
 	/*
 	 * We're the guest so this doesn't apply to us, clear it to simplify
 	 * handling of it elsewhere.
 	 */
 	security_ftr_clear(SEC_FTR_L1D_FLUSH_HV);
 
+	types = L1D_FLUSH_FALLBACK;
+
+	if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_TRIG2))
+		types |= L1D_FLUSH_MTTRIG;
+
+	if (security_ftr_enabled(SEC_FTR_L1D_FLUSH_ORI30))
+		types |= L1D_FLUSH_ORI;
+
+	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) && \
+		 security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR);
+
 	setup_rfi_flush(types, enable);
 }