diff options
| author | Madhavan Srinivasan <maddy@linux.vnet.ibm.com> | 2013-10-02 00:34:10 +0530 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-10-26 21:06:07 +0100 |
| commit | 28cfcc851d5c8a7075ea8bb9b8695bb376f6872d (patch) | |
| tree | 9b098d681e5cc3c143208c75c6dabb508f3af0cc /arch | |
| parent | 0b2d10f8f2e686c9f4b718251765f09f77ee8088 (diff) | |
powerpc/sysfs: Disable writing to PURR in guest mode
commit d1211af3049f4c9c1d8d4eb8f8098cc4f4f0d0c7 upstream.
arch/powerpc/kernel/sysfs.c exports PURR with write permission.
This may be valid for kernel in phyp mode. But writing to
the file in guest mode causes crash due to a priviledge violation
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[bwh: Backported to 3.2:
- Adjust context
- CPUs are sysdev and we must use the sysdev API]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/sysfs.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 55be64db0ae0..ca683a18943b 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -18,6 +18,7 @@ #include <asm/machdep.h> #include <asm/smp.h> #include <asm/pmc.h> +#include <asm/firmware.h> #include "cacheinfo.h" @@ -178,14 +179,24 @@ SYSFS_PMCSETUP(purr, SPRN_PURR); SYSFS_PMCSETUP(spurr, SPRN_SPURR); SYSFS_PMCSETUP(dscr, SPRN_DSCR); +/* + Lets only enable read for phyp resources and + enable write when needed with a separate function. + Lets be conservative and default to pseries. +*/ static SYSDEV_ATTR(mmcra, 0600, show_mmcra, store_mmcra); static SYSDEV_ATTR(spurr, 0600, show_spurr, NULL); static SYSDEV_ATTR(dscr, 0600, show_dscr, store_dscr); -static SYSDEV_ATTR(purr, 0600, show_purr, store_purr); +static SYSDEV_ATTR(purr, 0400, show_purr, store_purr); unsigned long dscr_default = 0; EXPORT_SYMBOL(dscr_default); +static void add_write_permission_dev_attr(struct sysdev_attribute *attr) +{ + attr->attr.mode |= 0200; +} + static ssize_t show_dscr_default(struct sysdev_class *class, struct sysdev_class_attribute *attr, char *buf) { @@ -394,8 +405,11 @@ static void __cpuinit register_cpu_online(unsigned int cpu) if (cpu_has_feature(CPU_FTR_MMCRA)) sysdev_create_file(s, &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(&attr_purr); sysdev_create_file(s, &attr_purr); + } if (cpu_has_feature(CPU_FTR_SPURR)) sysdev_create_file(s, &attr_spurr); |