commit 236003e6b5443c45c18e613d2b0d776a9f87540e upstream.
Expose the state of the RFI flush (enabled/disabled) via debugfs, and allow it to be enabled/disabled at runtime.
eg: $ cat /sys/kernel/debug/powerpc/rfi_flush 1 $ echo 0 > /sys/kernel/debug/powerpc/rfi_flush $ cat /sys/kernel/debug/powerpc/rfi_flush 0
Signed-off-by: Michael Ellerman mpe@ellerman.id.au Reviewed-by: Nicholas Piggin npiggin@gmail.com --- arch/powerpc/kernel/setup_64.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index cd7bfec17654..311b1f560f8a 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -38,7 +38,9 @@ #include <linux/hugetlb.h> #include <linux/memory.h> #include <linux/nmi.h> +#include <linux/debugfs.h>
+#include <asm/debug.h> #include <asm/io.h> #include <asm/kdump.h> #include <asm/prom.h> @@ -935,6 +937,35 @@ void __init setup_rfi_flush(enum l1d_flush_type types, bool enable) rfi_flush_enable(enable); }
+#ifdef CONFIG_DEBUG_FS +static int rfi_flush_set(void *data, u64 val) +{ + if (val == 1) + rfi_flush_enable(true); + else if (val == 0) + rfi_flush_enable(false); + else + return -EINVAL; + + return 0; +} + +static int rfi_flush_get(void *data, u64 *val) +{ + *val = rfi_flush ? 1 : 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n"); + +static __init int rfi_flush_debugfs_init(void) +{ + debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush); + return 0; +} +device_initcall(rfi_flush_debugfs_init); +#endif + ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { if (rfi_flush)