[PATCH RFC rebase 7/9] powerpc/64: barrier_nospec: Add debugfs trigger

[Michal Suchanek <msuchanek@suse.de>]

Copypasta from rfi implementation

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/setup_64.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index f60e0e3b5ad2..f6678a7b6114 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -963,6 +963,41 @@ static __init int rfi_flush_debugfs_init(void)
 	return 0;
 }
 device_initcall(rfi_flush_debugfs_init);
+
+static int barrier_nospec_set(void *data, u64 val)
+{
+	switch (val) {
+	case 0:
+	case 1:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (!!val == !!barrier_nospec_enabled)
+		return 0;
+
+	barrier_nospec_enable(!!val);
+
+	return 0;
+}
+
+static int barrier_nospec_get(void *data, u64 *val)
+{
+	*val = barrier_nospec_enabled ? 1 : 0;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
+			barrier_nospec_get, barrier_nospec_set, "%llu\n");
+
+static __init int barrier_nospec_debugfs_init(void)
+{
+	debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
+			    &fops_barrier_nospec);
+	return 0;
+}
+device_initcall(barrier_nospec_debugfs_init);
 #endif
 
 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
-- 
2.13.6