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Subject[PATCH 4.4 027/266] powerpc/64s: Enhance the information in cpu_show_meltdown()
Date
From: Michael Ellerman <mpe@ellerman.id.au>

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>
---
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");
}

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