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Subject[PATCH 09/11] powerpc/64s: Allow control of RFI flush via sysfs
Date
From: Nicholas Piggin <npiggin@gmail.com>

Expose the state of the RFI flush (enabled/disabled) via sysfs, and
allow it to be enabled/dissabled at runtime.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/kernel/setup.h | 2 ++
arch/powerpc/kernel/sysfs.c | 41 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 43 insertions(+)

diff --git a/arch/powerpc/kernel/setup.h b/arch/powerpc/kernel/setup.h
index 21c18071d9d5..493b03b0a966 100644
--- a/arch/powerpc/kernel/setup.h
+++ b/arch/powerpc/kernel/setup.h
@@ -61,4 +61,6 @@ void kvm_cma_reserve(void);
static inline void kvm_cma_reserve(void) { };
#endif

+extern bool rfi_flush;
+
#endif /* __ARCH_POWERPC_KERNEL_SETUP_H */
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index b8d4a1dac39f..8c19d014cffc 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -20,6 +20,7 @@
#include <asm/firmware.h>

#include "cacheinfo.h"
+#include "setup.h"

#ifdef CONFIG_PPC64
#include <asm/paca.h>
@@ -496,6 +497,43 @@ static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
static DEVICE_ATTR(pir, 0400, show_pir, NULL);

+#ifdef CONFIG_PPC_BOOK3S_64
+static ssize_t show_rfi_flush(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", rfi_flush ? 1 : 0);
+}
+
+static ssize_t __used store_rfi_flush(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ int val;
+ int ret = 0;
+
+ ret = sscanf(buf, "%d", &val);
+ if (ret != 1)
+ return -EINVAL;
+
+ if (val == 1)
+ rfi_flush_enable(true);
+ else if (val == 0)
+ rfi_flush_enable(false);
+ else
+ return -EINVAL;
+
+ return count;
+}
+
+static DEVICE_ATTR(rfi_flush, 0600,
+ show_rfi_flush, store_rfi_flush);
+
+static void sysfs_create_rfi_flush(void)
+{
+ device_create_file(cpu_subsys.dev_root, &dev_attr_rfi_flush);
+}
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
/*
* This is the system wide DSCR register default value. Any
* change to this default value through the sysfs interface
@@ -1047,6 +1085,9 @@ static int __init topology_init(void)
WARN_ON(r < 0);
#ifdef CONFIG_PPC64
sysfs_create_dscr_default();
+#ifdef CONFIG_PPC_BOOK3S
+ sysfs_create_rfi_flush();
+#endif
#endif /* CONFIG_PPC64 */

return 0;
--
2.14.3
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