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

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 <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h
index db00ad2..400a905 100644 (file)
--- 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)
 {

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 564e7f1..865db6f 100644 (file)
--- 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 __read_mostly = \
 
 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");
 }