diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2018-01-16 22:17:18 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-07 11:12:17 -0800 |
| commit | d6eded6c94530cb2f359f1fbffcb5f92ee0fa8b2 (patch) | |
| tree | 59eb870f67850ff0264c4ae983888f8fae81be63 /arch/powerpc/kernel | |
| parent | 517bdccc3af650316046801fdcd828d7b6aa42ba (diff) | |
powerpc/64s: Allow control of RFI flush via debugfs
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/setup_64.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 4fac5cca19e1..9527a4c6cbc2 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> @@ -885,6 +886,35 @@ 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) |