* [PATCH] powerpc/64s: Allow control of RFI flush via debugfs
@ 2018-01-16 11:24 Michael Ellerman
2018-01-16 14:41 ` Nicholas Piggin
2018-01-17 13:25 ` Michael Ellerman
0 siblings, 2 replies; 3+ messages in thread
From: Michael Ellerman @ 2018-01-16 11:24 UTC (permalink / raw)
To: linuxppc-dev; +Cc: npiggin
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>
---
arch/powerpc/kernel/setup_64.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 624d2a62d05d..e67413f4a8f0 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -38,6 +38,7 @@
#include <linux/memory.h>
#include <linux/nmi.h>
+#include <asm/debugfs.h>
#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/prom.h>
@@ -902,6 +903,35 @@ 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)
--
2.14.3
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] powerpc/64s: Allow control of RFI flush via debugfs
2018-01-16 11:24 [PATCH] powerpc/64s: Allow control of RFI flush via debugfs Michael Ellerman
@ 2018-01-16 14:41 ` Nicholas Piggin
2018-01-17 13:25 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Nicholas Piggin @ 2018-01-16 14:41 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxppc-dev
On Tue, 16 Jan 2018 22:24:31 +1100
Michael Ellerman <mpe@ellerman.id.au> wrote:
> 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 | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 624d2a62d05d..e67413f4a8f0 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -38,6 +38,7 @@
> #include <linux/memory.h>
> #include <linux/nmi.h>
>
> +#include <asm/debugfs.h>
> #include <asm/io.h>
> #include <asm/kdump.h>
> #include <asm/prom.h>
> @@ -902,6 +903,35 @@ 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)
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: powerpc/64s: Allow control of RFI flush via debugfs
2018-01-16 11:24 [PATCH] powerpc/64s: Allow control of RFI flush via debugfs Michael Ellerman
2018-01-16 14:41 ` Nicholas Piggin
@ 2018-01-17 13:25 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2018-01-17 13:25 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: npiggin
On Tue, 2018-01-16 at 11:24:31 UTC, Michael Ellerman wrote:
> 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>
Applied to powerpc fixes.
https://git.kernel.org/powerpc/c/236003e6b5443c45c18e613d2b0d77
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
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2018-01-16 14:41 ` Nicholas Piggin
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