Message ID | 1380268926-21338-1-git-send-email-maddy@linux.vnet.ibm.com (mailing list archive) |
---|---|
State | Superseded |
Headers | show |
On Fri, 2013-09-27 at 13:32 +0530, Madhavan Srinivasan wrote: > powerpc/kernel/sysfs.c exports purr with write permission. > This may be valid for powernv kernel since purr is Hyp resource. > But writing to the file in PowerVM lpar causes crash. Testing powernv isn't right, you should test for hypervisor mode. Cheers, Ben. > # echo 0 > purr > cpu 0x0: Vector: 700 (Program Check) at [c000000000d072b0] > pc: c00000000001770c: .write_purr+0x1c/0x40 > lr: c000000000017708: .write_purr+0x18/0x40 > sp: c000000000d07530 > msr: 8000000000049032 > current = 0xc000000000c53de0 > paca = 0xc00000000ec70000 softe: 0 irq_happened: 0x01 > pid = 0, comm = swapper/0 > enter ? for help > [c000000000d075b0] c0000000000fba64 > .generic_smp_call_function_single_interrupt+0x104/0x190 > [c000000000d07650] c000000000037748 .smp_ipi_demux+0xa8/0xf0 > [c000000000d076e0] c000000000035314 .doorbell_exception+0x74/0xb0 > [c000000000d07760] c000000000002950 doorbell_super_common+0x150/0x180 > --- Exception: a01 (Doorbell) at c000000000060904 > .plpar_hcall_norets+0x84/0xd4 > [link register ] c00000000006dbd4 .check_and_cede_processor+0x24/0x40 > [c000000000d07a50] c000000001002558 (unreliable) > [c000000000d07ac0] c00000000006dd0c .shared_cede_loop+0x2c/0x70 > [c000000000d07b40] c0000000006ae954 .cpuidle_enter_state+0x64/0x150 > [c000000000d07c00] c0000000006aeb30 .cpuidle_idle_call+0xf0/0x300 > [c000000000d07cb0] c000000000062fa0 .pseries_lpar_idle+0x10/0x50 > [c000000000d07d20] c000000000016d14 .arch_cpu_idle+0x64/0x150 > [c000000000d07da0] c0000000000e0060 .cpu_startup_entry+0x1a0/0x2c0 > [c000000000d07e80] c00000000000bca4 .rest_init+0x94/0xb0 > [c000000000d07ef0] c000000000b54530 .start_kernel+0x478/0x494 > [c000000000d07f90] c000000000009be0 .start_here_common+0x20/0x40 > 0:mon> > > Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> > --- > arch/powerpc/kernel/sysfs.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c > index 27a90b9..d7097c2 100644 > --- a/arch/powerpc/kernel/sysfs.c > +++ b/arch/powerpc/kernel/sysfs.c > @@ -179,15 +179,27 @@ SYSFS_PMCSETUP(spurr, SPRN_SPURR); > SYSFS_PMCSETUP(dscr, SPRN_DSCR); > SYSFS_PMCSETUP(pir, SPRN_PIR); > > +/* > + Lets only enable Read for Hyp 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(void *ptr) > +{ > + struct device_attribute *attr = (struct device_attribute *)ptr; > + > + attr->attr.mode |= (unsigned short) 0200; > +} > + > static ssize_t show_dscr_default(struct device *dev, > struct device_attribute *attr, char *buf) > { > @@ -394,8 +406,11 @@ 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 (machine_is(powernv)) > + add_write_permission_dev_attr((void *)&dev_attr_purr); > device_create_file(s, &dev_attr_purr); > + } > > if (cpu_has_feature(CPU_FTR_SPURR)) > device_create_file(s, &dev_attr_spurr);
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index 27a90b9..d7097c2 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -179,15 +179,27 @@ SYSFS_PMCSETUP(spurr, SPRN_SPURR); SYSFS_PMCSETUP(dscr, SPRN_DSCR); SYSFS_PMCSETUP(pir, SPRN_PIR); +/* + Lets only enable Read for Hyp 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(void *ptr) +{ + struct device_attribute *attr = (struct device_attribute *)ptr; + + attr->attr.mode |= (unsigned short) 0200; +} + static ssize_t show_dscr_default(struct device *dev, struct device_attribute *attr, char *buf) { @@ -394,8 +406,11 @@ 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 (machine_is(powernv)) + add_write_permission_dev_attr((void *)&dev_attr_purr); device_create_file(s, &dev_attr_purr); + } if (cpu_has_feature(CPU_FTR_SPURR)) device_create_file(s, &dev_attr_spurr);
powerpc/kernel/sysfs.c exports purr with write permission. This may be valid for powernv kernel since purr is Hyp resource. But writing to the file in PowerVM lpar causes crash. # echo 0 > purr cpu 0x0: Vector: 700 (Program Check) at [c000000000d072b0] pc: c00000000001770c: .write_purr+0x1c/0x40 lr: c000000000017708: .write_purr+0x18/0x40 sp: c000000000d07530 msr: 8000000000049032 current = 0xc000000000c53de0 paca = 0xc00000000ec70000 softe: 0 irq_happened: 0x01 pid = 0, comm = swapper/0 enter ? for help [c000000000d075b0] c0000000000fba64 .generic_smp_call_function_single_interrupt+0x104/0x190 [c000000000d07650] c000000000037748 .smp_ipi_demux+0xa8/0xf0 [c000000000d076e0] c000000000035314 .doorbell_exception+0x74/0xb0 [c000000000d07760] c000000000002950 doorbell_super_common+0x150/0x180 --- Exception: a01 (Doorbell) at c000000000060904 .plpar_hcall_norets+0x84/0xd4 [link register ] c00000000006dbd4 .check_and_cede_processor+0x24/0x40 [c000000000d07a50] c000000001002558 (unreliable) [c000000000d07ac0] c00000000006dd0c .shared_cede_loop+0x2c/0x70 [c000000000d07b40] c0000000006ae954 .cpuidle_enter_state+0x64/0x150 [c000000000d07c00] c0000000006aeb30 .cpuidle_idle_call+0xf0/0x300 [c000000000d07cb0] c000000000062fa0 .pseries_lpar_idle+0x10/0x50 [c000000000d07d20] c000000000016d14 .arch_cpu_idle+0x64/0x150 [c000000000d07da0] c0000000000e0060 .cpu_startup_entry+0x1a0/0x2c0 [c000000000d07e80] c00000000000bca4 .rest_init+0x94/0xb0 [c000000000d07ef0] c000000000b54530 .start_kernel+0x478/0x494 [c000000000d07f90] c000000000009be0 .start_here_common+0x20/0x40 0:mon> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com> --- arch/powerpc/kernel/sysfs.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)