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Commit 9fed3978 authored by Michael Ellerman's avatar Michael Ellerman Committed by Greg Kroah-Hartman
Browse files

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: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1f0c936f

arch/powerpc/kernel/setup_64.c

+30 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/memblock.h>

#include <linux/memory.h>

#include <linux/nmi.h>

#include <linux/debugfs.h>



#include <asm/io.h>

#include <asm/kdump.h>
@@ -779,6 +780,35 @@ 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)