4.16-stable review patch. If anyone has any objections, please let me know.
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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"); }