From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753270AbdH2Lf3 (ORCPT ); Tue, 29 Aug 2017 07:35:29 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:47711 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753025AbdH2Lf2 (ORCPT ); Tue, 29 Aug 2017 07:35:28 -0400 Subject: Re: [PATCH V8] perf: Add PERF_SAMPLE_PHYS_ADDR To: kan.liang@intel.com, peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org Cc: acme@kernel.org, jolsa@redhat.com, tglx@linutronix.de, eranian@google.com, ak@linux.intel.com, mpe@ellerman.id.au References: <1503967969-48278-1-git-send-email-kan.liang@intel.com> From: Madhavan Srinivasan Date: Tue, 29 Aug 2017 17:05:15 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1503967969-48278-1-git-send-email-kan.liang@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-TM-AS-MML: disable x-cbid: 17082911-0012-0000-0000-0000025AA487 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17082911-0013-0000-0000-000007766FE1 Message-Id: <5af3f1ab-b139-2c41-3218-1cba5ee3803e@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-08-29_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1708290173 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 29 August 2017 06:22 AM, kan.liang@intel.com wrote: > From: Kan Liang > > 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. > > Add a new sample type for physical address. > > perf already has a facility to collect data virtual address. This patch > introduces a function to convert the virtual address to physical address. > The function is quite generic and can be extended to any architecture as > long as a virtual address is provided. > - 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. > > The new sample type requires collecting the virtual address. The > virtual address will not be output unless SAMPLE_ADDR is applied. > > For security, the physical address can only be exposed to root or > privileged user. Tested-by: Madhavan Srinivasan > > Signed-off-by: Kan Liang > --- > > This patch is kernel patch. > The user space patch can be found here. > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_kernel_msg2587093.html&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=3f2W2m24mqGnx1C8qDsVjM_Sd89MwbaDB37IJVL-h7w&m=bL7qsJKf8aRpvBVr07ODZxoQhPgxffpGFgN9A4iyACw&s=R1OMYJt1szqNhPZu8QQDDRCnQgHZiQzcCPzofF6FIF8&e= > > Changes since V7 > - Fix virt_addr_valid compile warning for MIPS architecture (LKP) > > arch/powerpc/perf/core-book3s.c | 3 ++- > arch/x86/events/intel/ds.c | 2 +- > 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 +++++++++++++++++++++++++++++++++++++++++ > 6 files changed, 56 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c > index 6c2d416..2e3eb74 100644 > --- a/arch/powerpc/perf/core-book3s.c > +++ b/arch/powerpc/perf/core-book3s.c > @@ -2039,7 +2039,8 @@ static void record_and_restart(struct perf_event *event, unsigned long val, > > perf_sample_data_init(&data, ~0ULL, event->hw.last_period); > > - if (event->attr.sample_type & PERF_SAMPLE_ADDR) > + if (event->attr.sample_type & > + (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR)) > perf_get_data_addr(regs, &data.addr); > > if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) { > diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c > index a322fed..0516f78 100644 > --- a/arch/x86/events/intel/ds.c > +++ b/arch/x86/events/intel/ds.c > @@ -1175,7 +1175,7 @@ static void setup_pebs_sample_data(struct perf_event *event, > else > regs->flags &= ~PERF_EFLAGS_EXACT; > > - if ((sample_type & PERF_SAMPLE_ADDR) && > + if ((sample_type & (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR)) && > x86_pmu.intel_cap.pebs_format >= 1) > data->addr = pebs->dla; > > 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..e8d5c5d 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((void *)(uintptr_t)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; > +} > + > 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); > } > > 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; >