powerpc/64s: Wire up cpu_show_meltdown()

The recent commit 87590ce6e373 ("sysfs/cpu: Add vulnerability folder")
added a generic folder and set of files for reporting information on
CPU vulnerabilities. One of those was for meltdown:

  /sys/devices/system/cpu/vulnerabilities/meltdown

This commit wires up that file for 64-bit Book3S powerpc.

For now we default to "Vulnerable" unless the RFI flush is enabled.
That may not actually be true on all hardware, further patches will
refine the reporting based on the CPU/platform etc. But for now we
default to being pessimists.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c51e6ce42e7a258d20b76f8331c6a8156ffda4b6..2ed525a44734cfaa62ba7125fab11225c1778a7a 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -166,6 +166,7 @@ config PPC
        select GENERIC_CLOCKEVENTS_BROADCAST    if SMP
        select GENERIC_CMOS_UPDATE
        select GENERIC_CPU_AUTOPROBE
+       select GENERIC_CPU_VULNERABILITIES      if PPC_BOOK3S_64
        select GENERIC_IRQ_SHOW
        select GENERIC_IRQ_SHOW_LEVEL
        select GENERIC_SMP_IDLE_THREAD

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 491be4179ddd989fed6cba1e63963bf47653f4ba..624d2a62d05deef9cba1d30821b8594f9311bf8c 100644 (file)
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -901,4 +901,12 @@ void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
        if (!no_rfi_flush)
                rfi_flush_enable(enable);
 }
+
+ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+{
+       if (rfi_flush)
+               return sprintf(buf, "Mitigation: RFI Flush\n");
+
+       return sprintf(buf, "Vulnerable\n");
+}
 #endif /* CONFIG_PPC_BOOK3S_64 */