Subject: Patch "powerpc/64s: Enhance the information in cpu_show_meltdown()" has been added to the 4.16-stable tree

From: <[email-masked]>
Date: Wed, 23 May 2018 19:23:12 +0200

This is a note to let you know that I've just added the patch titled

    powerpc/64s: Enhance the information in cpu_show_meltdown()

to the 4.16-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-64s-enhance-the-information-in-cpu_show_meltdown.patch
and it can be found in the queue-4.16 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email-masked]> know about it.

>>From foo@baz Wed May 23 19:18:22 CEST 2018
From: Michael Ellerman <[email-masked]>
Date: Wed, 23 May 2018 00:41:18 +1000
Subject: powerpc/64s: Enhance the information in cpu_show_meltdown()
To: [email-masked]
Cc: [email-masked], [email-masked], [email-masked]
Message-ID: <[email-masked]>

From: Michael Ellerman <[email-masked]>

commit ff348355e9c72493947be337bb4fae4fc1a41eba upstream.

Now that we have the security feature flags we can make the
information displayed in the "meltdown" file more informative.

Signed-off-by: Michael Ellerman <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>
---
 arch/powerpc/include/asm/security_features.h |    1 
 arch/powerpc/kernel/security.c               |   30 +++++++++++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

--- a/arch/powerpc/include/asm/security_features.h
+++ b/arch/powerpc/include/asm/security_features.h
@@ -10,6 +10,7 @@

 extern unsigned long powerpc_security_features;
+extern bool rfi_flush;
 
 static inline void security_ftr_set(unsigned long feature)
 {
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -6,6 +6,7 @@
 
 #include <linux/kernel.h>
 #include <linux/device.h>
+#include <linux/seq_buf.h>
 
 #include <asm/security_features.h>
 
@@ -19,8 +20,33 @@ unsigned long powerpc_security_features
 
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	if (rfi_flush)
-		return sprintf(buf, "Mitigation: RFI Flush\n");
+	bool thread_priv;
+
+	thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);
+
+	if (rfi_flush || thread_priv) {
+		struct seq_buf s;
+		seq_buf_init(&s, buf, PAGE_SIZE - 1);
+
+		seq_buf_printf(&s, "Mitigation: ");
+
+		if (rfi_flush)
+			seq_buf_printf(&s, "RFI Flush");
+
+		if (rfi_flush && thread_priv)
+			seq_buf_printf(&s, ", ");
+
+		if (thread_priv)
+			seq_buf_printf(&s, "L1D private per thread");
+
+		seq_buf_printf(&s, "\n");
+
+		return s.len;
+	}
+
+	if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
+	    !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
+		return sprintf(buf, "Not affected\n");
 
 	return sprintf(buf, "Vulnerable\n");
 }

Patches currently in stable-queue which might be from [email-masked] are

queue-4.16/powerpc-pseries-fix-clearing-of-security-feature-flags.patch
queue-4.16/powerpc-powernv-set-or-clear-security-feature-flags.patch
queue-4.16/powerpc-64s-move-cpu_show_meltdown.patch
queue-4.16/powerpc-pseries-set-or-clear-security-feature-flags.patch
queue-4.16/powerpc-move-default-security-feature-flags.patch
queue-4.16/powerpc-powernv-use-the-security-flags-in-pnv_setup_rfi_flush.patch
queue-4.16/powerpc-add-security-feature-flags-for-spectre-meltdown.patch
queue-4.16/powerpc-pseries-use-the-security-flags-in-pseries_setup_rfi_flush.patch
queue-4.16/powerpc-64s-enhance-the-information-in-cpu_show_meltdown.patch
queue-4.16/powerpc-rfi-flush-always-enable-fallback-flush-on-pseries.patch
queue-4.16/powerpc-pseries-add-new-h_get_cpu_characteristics-flags.patch
queue-4.16/powerpc-64s-add-support-for-a-store-forwarding-barrier-at-kernel-entry-exit.patch
queue-4.16/powerpc-64s-wire-up-cpu_show_spectre_v1.patch
queue-4.16/powerpc-64s-wire-up-cpu_show_spectre_v2.patch