powerpc/sysfs: Disable writing to PURR in guest mode (d1211af3) · Commits · 戴 / test

arch/powerpc/kernel/sysfs.c

+16 −2

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#include <asm/machdep.h>
		#include <asm/smp.h>
		#include <asm/pmc.h>
		#include <asm/firmware.h>

		#include "cacheinfo.h"

		@@ -179,15 +180,25 @@ SYSFS_PMCSETUP(spurr, SPRN_SPURR);
		SYSFS_PMCSETUP(dscr, SPRN_DSCR);
		SYSFS_PMCSETUP(pir, SPRN_PIR);

		/*
		Lets only enable read for phyp resources and
		enable write when needed with a separate function.
		Lets be conservative and default to pseries.
		*/
		static DEVICE_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
		static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
		static DEVICE_ATTR(dscr, 0600, show_dscr, store_dscr);
		static DEVICE_ATTR(purr, 0600, show_purr, store_purr);
		static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
		static DEVICE_ATTR(pir, 0400, show_pir, NULL);

		unsigned long dscr_default = 0;
		EXPORT_SYMBOL(dscr_default);

		static void add_write_permission_dev_attr(struct device_attribute *attr)
		{
		attr->attr.mode \|= 0200;
		}

		static ssize_t show_dscr_default(struct device *dev,
		struct device_attribute attr, char buf)
		{
		@@ -394,8 +405,11 @@ static void register_cpu_online(unsigned int cpu)
		if (cpu_has_feature(CPU_FTR_MMCRA))
		device_create_file(s, &dev_attr_mmcra);

		if (cpu_has_feature(CPU_FTR_PURR))
		if (cpu_has_feature(CPU_FTR_PURR)) {
		if (!firmware_has_feature(FW_FEATURE_LPAR))
		add_write_permission_dev_attr(&dev_attr_purr);
		device_create_file(s, &dev_attr_purr);
		}

		if (cpu_has_feature(CPU_FTR_SPURR))
		device_create_file(s, &dev_attr_spurr);