Michael, Maddy, Since PPC implements PERF_SAMPLE_ADDR this affects you guys too, please have a look.
On Wed, Aug 23, 2017 at 10:22:46AM -0400, kan.li...@intel.com wrote: > From: Kan Liang <kan.li...@intel.com> > > For understanding how the workload maps to memory channels and hardware > behavior, it's very important to collect address maps with physical > addresses. For example, 3D XPoint access can only be found by filtering > the physical address. > However, perf doesn't collect physical address information in sampling. > > The virtual address which stored in data->addr can be used to calculate > the physical address. > For kernel direct mapping addresses, virt_to_phys is used to convert the > virtual addresses to physical address. > For user virtual addresses, __get_user_pages_fast is used to walk the > pages tables for user physical address. > This does not work for vmalloc addresses. Right now these are not > resolved, but code to do that could be added. > For security, the physical address can only be exposed to root or > privileged user. > A new sample type PERF_SAMPLE_PHYS_ADDR is introduced to expose the > physical addresses. Please reflow that.. > Signed-off-by: Kan Liang <kan.li...@intel.com> > --- > > This patch is kernel patch. > The user space patch can be found here. > https://www.spinics.net/lists/kernel/msg2587093.html > > Changes since V5 > - Move virt_to_phys to generic code (PeterZ) > > arch/x86/events/perf_event.h | 2 +- > include/linux/perf_event.h | 2 ++ > include/uapi/linux/perf_event.h | 4 +++- > kernel/events/core.c | 47 > +++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 53 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h > index 476aec3..65bb91e 100644 > --- a/arch/x86/events/perf_event.h > +++ b/arch/x86/events/perf_event.h > @@ -91,7 +91,7 @@ struct amd_nb { > (PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_ADDR | \ > PERF_SAMPLE_ID | PERF_SAMPLE_CPU | PERF_SAMPLE_STREAM_ID | \ > PERF_SAMPLE_DATA_SRC | PERF_SAMPLE_IDENTIFIER | \ > - PERF_SAMPLE_TRANSACTION) > + PERF_SAMPLE_TRANSACTION | PERF_SAMPLE_PHYS_ADDR) > > /* > * A debug store configuration. > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index b14095b..74fb87e 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -944,6 +944,8 @@ struct perf_sample_data { > > struct perf_regs regs_intr; > u64 stack_user_size; > + > + u64 phys_addr; > } ____cacheline_aligned; > > /* default value for data source */ > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h > index 642db5f..cbea02f 100644 > --- a/include/uapi/linux/perf_event.h > +++ b/include/uapi/linux/perf_event.h > @@ -139,8 +139,9 @@ enum perf_event_sample_format { > PERF_SAMPLE_IDENTIFIER = 1U << 16, > PERF_SAMPLE_TRANSACTION = 1U << 17, > PERF_SAMPLE_REGS_INTR = 1U << 18, > + PERF_SAMPLE_PHYS_ADDR = 1U << 19, > > - PERF_SAMPLE_MAX = 1U << 19, /* non-ABI */ > + PERF_SAMPLE_MAX = 1U << 20, /* non-ABI */ > }; > > /* > @@ -814,6 +815,7 @@ enum perf_event_type { > * { u64 transaction; } && > PERF_SAMPLE_TRANSACTION > * { u64 abi; # enum perf_sample_regs_abi > * u64 regs[weight(mask)]; } && > PERF_SAMPLE_REGS_INTR > + * { u64 phys_addr;} && PERF_SAMPLE_PHYS_ADDR > * }; > */ > PERF_RECORD_SAMPLE = 9, > diff --git a/kernel/events/core.c b/kernel/events/core.c > index d704e23..b991af3 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -1570,6 +1570,9 @@ static void __perf_event_header_size(struct perf_event > *event, u64 sample_type) > if (sample_type & PERF_SAMPLE_TRANSACTION) > size += sizeof(data->txn); > > + if (sample_type & PERF_SAMPLE_PHYS_ADDR) > + size += sizeof(data->phys_addr); > + > event->header_size = size; > } > > @@ -6012,6 +6015,9 @@ void perf_output_sample(struct perf_output_handle > *handle, > } > } > > + if (sample_type & PERF_SAMPLE_PHYS_ADDR) > + perf_output_put(handle, data->phys_addr); > + > if (!event->attr.watermark) { > int wakeup_events = event->attr.wakeup_events; > > @@ -6027,6 +6033,38 @@ void perf_output_sample(struct perf_output_handle > *handle, > } > } > > +static u64 perf_virt_to_phys(u64 virt) > +{ > + u64 phys_addr = 0; > + struct page *p = NULL; > + > + if (!virt) > + return 0; > + > + if (virt >= TASK_SIZE) { > + /* If it's vmalloc()d memory, leave phys_addr as 0 */ > + if (virt_addr_valid(virt) && > + !(virt >= VMALLOC_START && virt < VMALLOC_END)) > + phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); > + } else { > + /* > + * Walking the pages tables for user address. > + * Interrupts are disabled, so it prevents any tear down > + * of the page tables. > + * Try IRQ-safe __get_user_pages_fast first. > + * If failed, leave phys_addr as 0. > + */ > + if ((current->mm != NULL) && > + (__get_user_pages_fast(virt, 1, 0, &p) == 1)) > + phys_addr = page_to_phys(p) + virt % PAGE_SIZE; > + > + if (p) > + put_page(p); > + } > + > + return phys_addr; > +} Michael, does this work for PPC as is? > + > void perf_prepare_sample(struct perf_event_header *header, > struct perf_sample_data *data, > struct perf_event *event, > @@ -6145,6 +6183,9 @@ void perf_prepare_sample(struct perf_event_header > *header, > > header->size += size; > } > + > + if (sample_type & PERF_SAMPLE_PHYS_ADDR) > + data->phys_addr = perf_virt_to_phys(data->addr); Only problem with this now is that it requires SAMPLE_ADDR to also be set in order to obtain data->addr. Either fix all to set data->attr for (SAMPLE_ADDR || SAMPLE_PHYS_ADDR) or mandate SAMPLE_ADDR when SAMPLE_PHYS_ADDR. > } > > static void __always_inline > @@ -9892,6 +9933,12 @@ SYSCALL_DEFINE5(perf_event_open, > return -EINVAL; > } > > + /* Only privileged users can get kernel addresses */ > + if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) && > + perf_paranoid_kernel() && > + !capable(CAP_SYS_ADMIN)) > + return -EACCES; > + > if (!attr.sample_max_stack) > attr.sample_max_stack = sysctl_perf_event_max_stack; > > -- > 2.4.3 >
