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FAILED: patch "[PATCH] powerpc64s: Show ori31 availability in spectre_v1 sysfs file" failed to apply to 4.14-stable tree

PATCH [email protected] 1 participant 1 message Aug 22, 2018

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The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 6d44acae1937b81cf8115ada8958e04f601f3f2e Mon Sep 17 00:00:00 2001

From: Michael Ellerman <[email protected]>
Date: Mon, 9 Jul 2018 16:25:21 +1000
Subject: [PATCH] powerpc64s: Show ori31 availability in spectre_v1 sysfs file
not v2

When I added the spectre_v2 information in sysfs, I included the availability of the ori31 speculation barrier.

Although the ori31 barrier can be used to mitigate v2, it's primarily intended as a spectre v1 mitigation. Spectre v2 is mitigated by hardware changes.

So rework the sysfs files to show the ori31 information in the spectre_v1 file, rather than v2.

Currently we display eg:

  $ grep . spectre_v*
  spectre_v1:Mitigation: __user pointer sanitization
  spectre_v2:Mitigation: Indirect branch cache disabled, ori31 speculation barrier enabled

After:

  $ grep . spectre_v*
  spectre_v1:Mitigation: __user pointer sanitization, ori31 speculation barrier enabled
  spectre_v2:Mitigation: Indirect branch cache disabled
Fixes d6fbe1c55c55 ("powerpc/64s: Wire up cpu_show_spectre_v2()")
Cc [email protected] # v4.17+
Signed-off-by Michael Ellerman <[email protected]>
arch/powerpc/kernel/security.c +17 -10
index a8b277362931..4cb8f1f7b593 100644
@@ -117,25 +117,35 @@ ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, cha
 
 ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	if (!security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR))
-		return sprintf(buf, "Not affected\n");
+	struct seq_buf s;
+
+	seq_buf_init(&s, buf, PAGE_SIZE - 1);
 
-	if (barrier_nospec_enabled)
-		return sprintf(buf, "Mitigation: __user pointer sanitization\n");
+	if (security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) {
+		if (barrier_nospec_enabled)
+			seq_buf_printf(&s, "Mitigation: __user pointer sanitization");
+		else
+			seq_buf_printf(&s, "Vulnerable");
 
-	return sprintf(buf, "Vulnerable\n");
+		if (security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31))
+			seq_buf_printf(&s, ", ori31 speculation barrier enabled");
+
+		seq_buf_printf(&s, "\n");
+	} else
+		seq_buf_printf(&s, "Not affected\n");
+
+	return s.len;
 }
 
 ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	bool bcs, ccd, ori;
 	struct seq_buf s;
+	bool bcs, ccd;
 
 	seq_buf_init(&s, buf, PAGE_SIZE - 1);
 
 	bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
 	ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
-	ori = security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31);
 
 	if (bcs || ccd) {
 		seq_buf_printf(&s, "Mitigation: ");

@@ -151,9 +161,6 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, c
 	} else
 		seq_buf_printf(&s, "Vulnerable");
 
-	if (ori)
-		seq_buf_printf(&s, ", ori31 speculation barrier enabled");
-
 	seq_buf_printf(&s, "\n");
 
 	return s.len;