[PATCH] L1TF support in PowerPC SYSFS.

[asteinhauser at google.com]

From: Anthony Steinhauser <asteinhauser at google.com>

PowerPC CPUs are vulnerable to L1TF to the same extent as to Meltdown.
It is also mitigated by flushing the L1D on privilege transition.
Currently the SYSFS gives a false negative on L1TF on CPUs that I verified
to be vulnerable.
https://www.ibm.com/blogs/psirt/potential-impact-processors-power-family/
https://github.com/google/safeside/pull/52
Signed-off-by: Anthony Steinhauser <asteinhauser at google.com>
---
 arch/powerpc/kernel/security.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 7cfcb294b11c..a1a5017c5170 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -135,7 +135,8 @@ void setup_spectre_v2(void)
 #endif /* CONFIG_PPC_FSL_BOOK3E */
 
 #ifdef CONFIG_PPC_BOOK3S_64
-ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t cpu_show_delayed_fault_common(
+		struct device *dev, struct device_attribute *attr, char *buf)
 {
 	bool thread_priv;
 
@@ -167,6 +168,16 @@ ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, cha
 
 	return sprintf(buf, "Vulnerable\n");
 }
+
+ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_delayed_fault_common(dev, attr, buf);
+}
+
+ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return cpu_show_delayed_fault_common(dev, attr, buf);
+}
 #endif
 
 ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
-- 
2.24.0.rc0.303.g954a862665-goog