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[PATCH V13 00/14] perf/core: Add ability for an event to "pause" or "resume" AUX area tracing

by Adrian Hunter

Hi Note for V12: There was a small conflict between the Intel PT changes in "KVM: x86: Fix Intel PT Host/Guest mode when host tracing" and the changes in this patch set, so I have put the patch sets together, along with outstanding fix "perf/x86/intel/pt: Fix buffer full but size is 0 case" Cover letter for KVM changes (patches 2 to 4): There is a long-standing problem whereby running Intel PT on host and guest in Host/Guest mode, causes VM-Entry failure. The motivation for this patch set is to provide a fix for stable kernels prior to the advent of the "Mediated Passthrough vPMU" patch set: https://lore.kernel.org/kvm/20240801045907.4010984-1-mizhang@google.com/ which would render a large part of the fix unnecessary but likely not be suitable for backport to stable due to its size and complexity. Ideally, this patch set would be applied before "Mediated Passthrough vPMU" Note that the fix does not conflict with "Mediated Passthrough vPMU", it is just that "Mediated Passthrough vPMU" will make the code to stop and restart Intel PT unnecessary. Note for V11: Moving aux_paused into a union within struct hw_perf_event caused a regression because aux_paused was being written unconditionally even though it is valid only for AUX (e.g. Intel PT) PMUs. That is fixed in V11. Hardware traces, such as instruction traces, can produce a vast amount of trace data, so being able to reduce tracing to more specific circumstances can be useful. The ability to pause or resume tracing when another event happens, can do that. These patches add such a facilty and show how it would work for Intel Processor Trace. Maintainers of other AUX area tracing implementations are requested to consider if this is something they might employ and then whether or not the ABI would work for them. Note, thank you to James Clark (ARM) for evaluating the API for Coresight. Suzuki K Poulose (ARM) also responded positively to the RFC. Changes to perf tools are now (since V4) fleshed out. Please note, Intel® Architecture Instruction Set Extensions and Future Features Programming Reference March 2024 319433-052, currently: https://cdrdv2.intel.com/v1/dl/getContent/671368 introduces hardware pause / resume for Intel PT in a feature named Intel PT Trigger Tracing. For that more fields in perf_event_attr will be necessary. The main differences are: - it can be applied not just to overflows, but optionally to every event - a packet is emitted into the trace, optionally with IP information - no PMI - works with PMC and DR (breakpoint) events only Here are the proposed additions to perf_event_attr, please comment: diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h index 0c557f0a17b3..05dcc43f11bb 100644 --- a/tools/include/uapi/linux/perf_event.h +++ b/tools/include/uapi/linux/perf_event.h @@ -369,6 +369,22 @@ enum perf_event_read_format { PERF_FORMAT_MAX = 1U << 5, /* non-ABI */ }; +enum { + PERF_AUX_ACTION_START_PAUSED = 1U << 0, + PERF_AUX_ACTION_PAUSE = 1U << 1, + PERF_AUX_ACTION_RESUME = 1U << 2, + PERF_AUX_ACTION_EMIT = 1U << 3, + PERF_AUX_ACTION_NR = 0x1f << 4, + PERF_AUX_ACTION_NO_IP = 1U << 9, + PERF_AUX_ACTION_PAUSE_ON_EVT = 1U << 10, + PERF_AUX_ACTION_RESUME_ON_EVT = 1U << 11, + PERF_AUX_ACTION_EMIT_ON_EVT = 1U << 12, + PERF_AUX_ACTION_NR_ON_EVT = 0x1f << 13, + PERF_AUX_ACTION_NO_IP_ON_EVT = 1U << 18, + PERF_AUX_ACTION_MASK = ~PERF_AUX_ACTION_START_PAUSED, + PERF_AUX_PAUSE_RESUME_MASK = PERF_AUX_ACTION_PAUSE | PERF_AUX_ACTION_RESUME, +}; + #define PERF_ATTR_SIZE_VER0 64 /* sizeof first published struct */ #define PERF_ATTR_SIZE_VER1 72 /* add: config2 */ #define PERF_ATTR_SIZE_VER2 80 /* add: branch_sample_type */ @@ -515,10 +531,19 @@ struct perf_event_attr { union { __u32 aux_action; struct { - __u32 aux_start_paused : 1, /* start AUX area tracing paused */ - aux_pause : 1, /* on overflow, pause AUX area tracing */ - aux_resume : 1, /* on overflow, resume AUX area tracing */ - __reserved_3 : 29; + __u32 aux_start_paused : 1, /* start AUX area tracing paused */ + aux_pause : 1, /* on overflow, pause AUX area tracing */ + aux_resume : 1, /* on overflow, resume AUX area tracing */ + aux_emit : 1, /* generate AUX records instead of events */ + aux_nr : 5, /* AUX area tracing reference number */ + aux_no_ip : 1, /* suppress IP in AUX records */ + /* Following apply to event occurrence not overflows */ + aux_pause_on_evt : 1, /* on event, pause AUX area tracing */ + aux_resume_on_evt : 1, /* on event, resume AUX area tracing */ + aux_emit_on_evt : 1, /* generate AUX records instead of events */ + aux_nr_on_evt : 5, /* AUX area tracing reference number */ + aux_no_ip_on_evt : 1, /* suppress IP in AUX records */ + __reserved_3 : 13; }; }; Changes in V13: perf/core: Add aux_pause, aux_resume, aux_start_paused Do aux_resume at the end of __perf_event_overflow() so as to trace less of perf itself perf tools: Add missing_features for aux_start_paused, aux_pause, aux_resume Add error message also in EOPNOTSUPP case (Leo) Changes in V12: Add previously sent patch "perf/x86/intel/pt: Fix buffer full but size is 0 case" Add previously sent patch set "KVM: x86: Fix Intel PT Host/Guest mode when host tracing" Rebase on current tip plus patch set "KVM: x86: Fix Intel PT Host/Guest mode when host tracing" Changes in V11: perf/core: Add aux_pause, aux_resume, aux_start_paused Make assignment to event->hw.aux_paused conditional on (pmu->capabilities & PERF_PMU_CAP_AUX_PAUSE). perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling Remove definition of has_aux_action() because it has already been added as an inline function. perf/x86/intel/pt: Fix sampling synchronization perf tools: Enable evsel__is_aux_event() to work for ARM/ARM64 perf tools: Enable evsel__is_aux_event() to work for S390_CPUMSF Dropped because they have already been applied Changes in V10: perf/core: Add aux_pause, aux_resume, aux_start_paused Move aux_paused into a union within struct hw_perf_event. Additional comment wrt PERF_EF_PAUSE/PERF_EF_RESUME. Factor out has_aux_action() as an inline function. Use scoped_guard for irqsave. Move calls of perf_event_aux_pause() from __perf_event_output() to __perf_event_overflow(). Changes in V9: perf/x86/intel/pt: Fix sampling synchronization New patch perf/core: Add aux_pause, aux_resume, aux_start_paused Move aux_paused to struct hw_perf_event perf/x86/intel/pt: Add support for pause / resume Add more comments and barriers for resume_allowed and pause_allowed Always use WRITE_ONCE with resume_allowed Changes in V8: perf tools: Parse aux-action Fix clang warning: util/auxtrace.c:821:7: error: missing field 'aux_action' initializer [-Werror,-Wmissing-field-initializers] 821 | {NULL}, | ^ Changes in V7: Add Andi's Reviewed-by for patches 2-12 Re-base Changes in V6: perf/core: Add aux_pause, aux_resume, aux_start_paused Removed READ/WRITE_ONCE from __perf_event_aux_pause() Expanded comment about guarding against NMI Changes in V5: perf/core: Add aux_pause, aux_resume, aux_start_paused Added James' Ack perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling New patch perf tools Added Ian's Ack Changes in V4: perf/core: Add aux_pause, aux_resume, aux_start_paused Rename aux_output_cfg -> aux_action Reorder aux_action bits from: aux_pause, aux_resume, aux_start_paused to: aux_start_paused, aux_pause, aux_resume Fix aux_action bits __u64 -> __u32 coresight: Have a stab at support for pause / resume Dropped perf tools All new patches Changes in RFC V3: coresight: Have a stab at support for pause / resume 'mode' -> 'flags' so it at least compiles Changes in RFC V2: Use ->stop() / ->start() instead of ->pause_resume() Move aux_start_paused bit into aux_output_cfg Tighten up when Intel PT pause / resume is allowed Add an example of how it might work for CoreSight Adrian Hunter (14): perf/x86/intel/pt: Fix buffer full but size is 0 case KVM: x86: Fix Intel PT IA32_RTIT_CTL MSR validation KVM: x86: Fix Intel PT Host/Guest mode when host tracing also KVM: selftests: Add guest Intel PT test perf/core: Add aux_pause, aux_resume, aux_start_paused perf/x86/intel/pt: Add support for pause / resume perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling perf tools: Add aux_start_paused, aux_pause and aux_resume perf tools: Add aux-action config term perf tools: Parse aux-action perf tools: Add missing_features for aux_start_paused, aux_pause, aux_resume perf intel-pt: Improve man page format perf intel-pt: Add documentation for pause / resume perf intel-pt: Add a test for pause / resume arch/x86/events/intel/core.c | 4 +- arch/x86/events/intel/pt.c | 209 +++++++- arch/x86/events/intel/pt.h | 16 + arch/x86/include/asm/intel_pt.h | 4 + arch/x86/kvm/vmx/vmx.c | 26 +- arch/x86/kvm/vmx/vmx.h | 1 - include/linux/perf_event.h | 28 + include/uapi/linux/perf_event.h | 11 +- kernel/events/core.c | 75 ++- kernel/events/internal.h | 1 + tools/include/uapi/linux/perf_event.h | 11 +- tools/perf/Documentation/perf-intel-pt.txt | 596 +++++++++++++-------- tools/perf/Documentation/perf-record.txt | 4 + tools/perf/builtin-record.c | 4 +- tools/perf/tests/shell/test_intel_pt.sh | 28 + tools/perf/util/auxtrace.c | 67 ++- tools/perf/util/auxtrace.h | 6 +- tools/perf/util/evsel.c | 15 + tools/perf/util/evsel.h | 1 + tools/perf/util/evsel_config.h | 1 + tools/perf/util/parse-events.c | 10 + tools/perf/util/parse-events.h | 1 + tools/perf/util/parse-events.l | 1 + tools/perf/util/perf_event_attr_fprintf.c | 3 + tools/perf/util/pmu.c | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/include/x86_64/processor.h | 1 + tools/testing/selftests/kvm/x86_64/intel_pt.c | 381 +++++++++++++ 28 files changed, 1243 insertions(+), 264 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86_64/intel_pt.c Regards Adrian

1 year, 2 months

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[PATCH net-next v5 0/3] Threads support in proc connector

by Anjali Kulkarni

Recently we committed a fix to allow processes to receive notifications for non-zero exits via the process connector module. Commit is a4c9a56e6a2c. However, for threads, when it does a pthread_exit(&exit_status) call, the kernel is not aware of the exit status with which pthread_exit is called. It is sent by child thread to the parent process, if it is waiting in pthread_join(). Hence, for a thread exiting abnormally, kernel cannot send notifications to any listening processes. The exception to this is if the thread is sent a signal which it has not handled, and dies along with it's process as a result; for eg. SIGSEGV or SIGKILL. In this case, kernel is aware of the non-zero exit and sends a notification for it. For our use case, we cannot have parent wait in pthread_join, one of the main reasons for this being that we do not want to track normal pthread_exit(), which could be a very large number. We only want to be notified of any abnormal exits. Hence, threads are created with pthread_attr_t set to PTHREAD_CREATE_DETACHED. To fix this problem, we add a new type PROC_CN_MCAST_NOTIFY to proc connector API, which allows a thread to send it's exit status to kernel either when it needs to call pthread_exit() with non-zero value to indicate some error or from signal handler before pthread_exit(). We also need to filter packets with non-zero exit notifications futher based on instances, which can be identified by task names. Hence, added a comm field to the packet's struct proc_event, in which task->comm is stored. v4->v5 changes: - Handled comment by Stanislav Fomichev to fix a print format error. - Made thread.c completely automated by starting proc_filter program from within threads.c. - Changed name CONFIG_CN_HASH_KUNIT_TEST to CN_HASH_KUNIT_TEST in Kconfig.debug and changed display text. v3->v4 changes: - Reduce size of exit.log by removing unnecessary text. v2->v3 changes: - Handled comment by Liam Howlett to set hdev to NULL and add comment on it. - Handled comment by Liam Howlett to combine functions for deleting+get and deleting into one in cn_hash.c - Handled comment by Liam Howlett to remove extern in the functions defined in cn_hash_test.h - Some nits by Liam Howlett fixed. - Handled comment by Liam Howlett to make threads test automated. proc_filter.c creates exit.log, which is read by thread.c and checks the values reported. - Added "comm" field to struct proc_event, to copy the task's name to the packet to allow further filtering by packets. v1->v2 changes: - Handled comment by Peter Zijlstra to remove locking for PF_EXIT_NOTIFY task->flags. - Added error handling in thread.c v->v1 changes: - Handled comment by Simon Horman to remove unused err in cn_proc.c - Handled comment by Simon Horman to make adata and key_display static in cn_hash_test.c Anjali Kulkarni (3): connector/cn_proc: Add hash table for threads connector/cn_proc: Kunit tests for threads hash table connector/cn_proc: Selftest for threads drivers/connector/Makefile | 2 +- drivers/connector/cn_hash.c | 221 +++++++++++++++++ drivers/connector/cn_proc.c | 62 ++++- drivers/connector/connector.c | 75 +++++- include/linux/connector.h | 35 +++ include/linux/sched.h | 2 +- include/uapi/linux/cn_proc.h | 5 +- lib/Kconfig.debug | 17 ++ lib/Makefile | 1 + lib/cn_hash_test.c | 167 +++++++++++++ lib/cn_hash_test.h | 10 + tools/testing/selftests/connector/Makefile | 23 +- .../testing/selftests/connector/proc_filter.c | 34 ++- tools/testing/selftests/connector/thread.c | 232 ++++++++++++++++++ .../selftests/connector/thread_filter.c | 96 ++++++++ 15 files changed, 967 insertions(+), 15 deletions(-) create mode 100644 drivers/connector/cn_hash.c create mode 100644 lib/cn_hash_test.c create mode 100644 lib/cn_hash_test.h create mode 100644 tools/testing/selftests/connector/thread.c create mode 100644 tools/testing/selftests/connector/thread_filter.c -- 2.46.0

1 year, 2 months

4
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[PATCH AUTOSEL 6.6 03/23] selftests/bpf: Verify that sync_linked_regs preserves subreg_def

by Sasha Levin

From: Eduard Zingerman <eddyz87(a)gmail.com> [ Upstream commit a41b3828ec056a631ad22413d4560017fed5c3bd ] This test was added because of a bug in verifier.c:sync_linked_regs(), upon range propagation it destroyed subreg_def marks for registers. The test is written in a way to return an upper half of a register that is affected by range propagation and must have it's subreg_def preserved. This gives a return value of 0 and leads to undefined return value if subreg_def mark is not preserved. Signed-off-by: Eduard Zingerman <eddyz87(a)gmail.com> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Acked-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240924210844.1758441-2-eddyz87@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- .../selftests/bpf/progs/verifier_scalar_ids.c | 67 +++++++++++++++++++ 1 file changed, 67 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c b/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c index 13b29a7faa71a..d24d3a36ec144 100644 --- a/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c +++ b/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c @@ -656,4 +656,71 @@ __naked void two_old_ids_one_cur_id(void) : __clobber_all); } +SEC("socket") +/* Note the flag, see verifier.c:opt_subreg_zext_lo32_rnd_hi32() */ +__flag(BPF_F_TEST_RND_HI32) +__success +/* This test was added because of a bug in verifier.c:sync_linked_regs(), + * upon range propagation it destroyed subreg_def marks for registers. + * The subreg_def mark is used to decide whether zero extension instructions + * are needed when register is read. When BPF_F_TEST_RND_HI32 is set it + * also causes generation of statements to randomize upper halves of + * read registers. + * + * The test is written in a way to return an upper half of a register + * that is affected by range propagation and must have it's subreg_def + * preserved. This gives a return value of 0 and leads to undefined + * return value if subreg_def mark is not preserved. + */ +__retval(0) +/* Check that verifier believes r1/r0 are zero at exit */ +__log_level(2) +__msg("4: (77) r1 >>= 32 ; R1_w=0") +__msg("5: (bf) r0 = r1 ; R0_w=0 R1_w=0") +__msg("6: (95) exit") +__msg("from 3 to 4") +__msg("4: (77) r1 >>= 32 ; R1_w=0") +__msg("5: (bf) r0 = r1 ; R0_w=0 R1_w=0") +__msg("6: (95) exit") +/* Verify that statements to randomize upper half of r1 had not been + * generated. + */ +__xlated("call unknown") +__xlated("r0 &= 2147483647") +__xlated("w1 = w0") +/* This is how disasm.c prints BPF_ZEXT_REG at the moment, x86 and arm + * are the only CI archs that do not need zero extension for subregs. + */ +#if !defined(__TARGET_ARCH_x86) && !defined(__TARGET_ARCH_arm64) +__xlated("w1 = w1") +#endif +__xlated("if w0 < 0xa goto pc+0") +__xlated("r1 >>= 32") +__xlated("r0 = r1") +__xlated("exit") +__naked void linked_regs_and_subreg_def(void) +{ + asm volatile ( + "call %[bpf_ktime_get_ns];" + /* make sure r0 is in 32-bit range, otherwise w1 = w0 won't + * assign same IDs to registers. + */ + "r0 &= 0x7fffffff;" + /* link w1 and w0 via ID */ + "w1 = w0;" + /* 'if' statement propagates range info from w0 to w1, + * but should not affect w1->subreg_def property. + */ + "if w0 < 10 goto +0;" + /* r1 is read here, on archs that require subreg zero + * extension this would cause zext patch generation. + */ + "r1 >>= 32;" + "r0 = r1;" + "exit;" + : + : __imm(bpf_ktime_get_ns) + : __clobber_all); +} + char _license[] SEC("license") = "GPL"; -- 2.43.0

1 year, 2 months

1
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[PATCH AUTOSEL 6.11 20/30] selftests/bpf: Assert link info uprobe_multi count & path_size if unset

by Sasha Levin

From: Tyrone Wu <wudevelops(a)gmail.com> [ Upstream commit b836cbdf3b81a4a22b3452186efa2e5105a77e10 ] Add assertions in `bpf_link_info.uprobe_multi` test to verify that `count` and `path_size` fields are correctly populated when the fields are unset. This tests a previous bug where the `path_size` field was not populated when `path` and `path_size` were unset. Signed-off-by: Tyrone Wu <wudevelops(a)gmail.com> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/bpf/20241011000803.681190-2-wudevelops@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaaf..59ef57145b63c 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -417,6 +417,15 @@ verify_umulti_link_info(int fd, bool retprobe, __u64 *offsets, if (!ASSERT_NEQ(err, -1, "readlink")) return -1; + memset(&info, 0, sizeof(info)); + err = bpf_link_get_info_by_fd(fd, &info, &len); + if (!ASSERT_OK(err, "bpf_link_get_info_by_fd")) + return -1; + + ASSERT_EQ(info.uprobe_multi.count, 3, "info.uprobe_multi.count"); + ASSERT_EQ(info.uprobe_multi.path_size, strlen(path) + 1, + "info.uprobe_multi.path_size"); + for (bit = 0; bit < 8; bit++) { memset(&info, 0, sizeof(info)); info.uprobe_multi.path = ptr_to_u64(path_buf); -- 2.43.0

1 year, 2 months

1
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[PATCH AUTOSEL 6.11 03/30] selftests/bpf: Verify that sync_linked_regs preserves subreg_def

by Sasha Levin

From: Eduard Zingerman <eddyz87(a)gmail.com> [ Upstream commit a41b3828ec056a631ad22413d4560017fed5c3bd ] This test was added because of a bug in verifier.c:sync_linked_regs(), upon range propagation it destroyed subreg_def marks for registers. The test is written in a way to return an upper half of a register that is affected by range propagation and must have it's subreg_def preserved. This gives a return value of 0 and leads to undefined return value if subreg_def mark is not preserved. Signed-off-by: Eduard Zingerman <eddyz87(a)gmail.com> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Signed-off-by: Daniel Borkmann <daniel(a)iogearbox.net> Acked-by: Daniel Borkmann <daniel(a)iogearbox.net> Link: https://lore.kernel.org/bpf/20240924210844.1758441-2-eddyz87@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- .../selftests/bpf/progs/verifier_scalar_ids.c | 67 +++++++++++++++++++ 1 file changed, 67 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c b/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c index 13b29a7faa71a..d24d3a36ec144 100644 --- a/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c +++ b/tools/testing/selftests/bpf/progs/verifier_scalar_ids.c @@ -656,4 +656,71 @@ __naked void two_old_ids_one_cur_id(void) : __clobber_all); } +SEC("socket") +/* Note the flag, see verifier.c:opt_subreg_zext_lo32_rnd_hi32() */ +__flag(BPF_F_TEST_RND_HI32) +__success +/* This test was added because of a bug in verifier.c:sync_linked_regs(), + * upon range propagation it destroyed subreg_def marks for registers. + * The subreg_def mark is used to decide whether zero extension instructions + * are needed when register is read. When BPF_F_TEST_RND_HI32 is set it + * also causes generation of statements to randomize upper halves of + * read registers. + * + * The test is written in a way to return an upper half of a register + * that is affected by range propagation and must have it's subreg_def + * preserved. This gives a return value of 0 and leads to undefined + * return value if subreg_def mark is not preserved. + */ +__retval(0) +/* Check that verifier believes r1/r0 are zero at exit */ +__log_level(2) +__msg("4: (77) r1 >>= 32 ; R1_w=0") +__msg("5: (bf) r0 = r1 ; R0_w=0 R1_w=0") +__msg("6: (95) exit") +__msg("from 3 to 4") +__msg("4: (77) r1 >>= 32 ; R1_w=0") +__msg("5: (bf) r0 = r1 ; R0_w=0 R1_w=0") +__msg("6: (95) exit") +/* Verify that statements to randomize upper half of r1 had not been + * generated. + */ +__xlated("call unknown") +__xlated("r0 &= 2147483647") +__xlated("w1 = w0") +/* This is how disasm.c prints BPF_ZEXT_REG at the moment, x86 and arm + * are the only CI archs that do not need zero extension for subregs. + */ +#if !defined(__TARGET_ARCH_x86) && !defined(__TARGET_ARCH_arm64) +__xlated("w1 = w1") +#endif +__xlated("if w0 < 0xa goto pc+0") +__xlated("r1 >>= 32") +__xlated("r0 = r1") +__xlated("exit") +__naked void linked_regs_and_subreg_def(void) +{ + asm volatile ( + "call %[bpf_ktime_get_ns];" + /* make sure r0 is in 32-bit range, otherwise w1 = w0 won't + * assign same IDs to registers. + */ + "r0 &= 0x7fffffff;" + /* link w1 and w0 via ID */ + "w1 = w0;" + /* 'if' statement propagates range info from w0 to w1, + * but should not affect w1->subreg_def property. + */ + "if w0 < 10 goto +0;" + /* r1 is read here, on archs that require subreg zero + * extension this would cause zext patch generation. + */ + "r1 >>= 32;" + "r0 = r1;" + "exit;" + : + : __imm(bpf_ktime_get_ns) + : __clobber_all); +} + char _license[] SEC("license") = "GPL"; -- 2.43.0

1 year, 2 months

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[PATCH v2 0/5] implement lightweight guard pages

by Lorenzo Stoakes

Userland library functions such as allocators and threading implementations often require regions of memory to act as 'guard pages' - mappings which, when accessed, result in a fatal signal being sent to the accessing process. The current means by which these are implemented is via a PROT_NONE mmap() mapping, which provides the required semantics however incur an overhead of a VMA for each such region. With a great many processes and threads, this can rapidly add up and incur a significant memory penalty. It also has the added problem of preventing merges that might otherwise be permitted. This series takes a different approach - an idea suggested by Vlasimil Babka (and before him David Hildenbrand and Jann Horn - perhaps more - the provenance becomes a little tricky to ascertain after this - please forgive any omissions!) - rather than locating the guard pages at the VMA layer, instead placing them in page tables mapping the required ranges. Early testing of the prototype version of this code suggests a 5 times speed up in memory mapping invocations (in conjunction with use of process_madvise()) and a 13% reduction in VMAs on an entirely idle android system and unoptimised code. We expect with optimisation and a loaded system with a larger number of guard pages this could significantly increase, but in any case these numbers are encouraging. This way, rather than having separate VMAs specifying which parts of a range are guard pages, instead we have a VMA spanning the entire range of memory a user is permitted to access and including ranges which are to be 'guarded'. After mapping this, a user can specify which parts of the range should result in a fatal signal when accessed. By restricting the ability to specify guard pages to memory mapped by existing VMAs, we can rely on the mappings being torn down when the mappings are ultimately unmapped and everything works simply as if the memory were not faulted in, from the point of view of the containing VMAs. This mechanism in effect poisons memory ranges similar to hardware memory poisoning, only it is an entirely software-controlled form of poisoning. Any poisoned region of memory is also able to 'unpoisoned', that is, to have its poison markers removed. The mechanism is implemented via madvise() behaviour - MADV_GUARD_POISON which simply poisons ranges - and MADV_GUARD_UNPOISON - which clears this poisoning. Poisoning can be performed across multiple VMAs and any existing mappings will be cleared, that is zapped, before installing the poisoned page table mappings. There is no concept of 'nested' poisoning, multiple attempts to poison a range will, after the first poisoning, have no effect. Importantly, unpoisoning of poisoned ranges has no effect on non-poisoned memory, so a user can safely unpoison a range of memory and clear only poison page table mappings leaving the rest intact. The actual mechanism by which the page table entries are specified makes use of existing logic - PTE markers, which are used for the userfaultfd UFFDIO_POISON mechanism. Unfortunately PTE_MARKER_POISONED is not suited for the guard page mechanism as it results in VM_FAULT_HWPOISON semantics in the fault handler, so we add our own specific PTE_MARKER_GUARD and adapt existing logic to handle it. We also extend the generic page walk mechanism to allow for installation of PTEs (carefully restricted to memory management logic only to prevent unwanted abuse). We ensure that zapping performed by, for instance, MADV_DONTNEED, does not remove guard poison markers, nor does forking (except when VM_WIPEONFORK is specified for a VMA which implies a total removal of memory characteristics). It's important to note that the guard page implementation is emphatically NOT a security feature, so a user can remove the poisoning if they wish. We simply implement it in such a way as to provide the least surprising behaviour. An extensive set of self-tests are provided which ensure behaviour is as expected and additionally self-documents expected behaviour of poisoned ranges. Suggested-by: Vlastimil Babka <vbabka(a)suse.cz> Suggested-by: Jann Horn <jannh(a)google.com> Suggested-by: David Hildenbrand <david(a)redhat.com> v2 * The macros in kselftest_harness.h seem to be broken - __EXPECT() is terminated by '} while (0); OPTIONAL_HANDLER(_assert)' meaning it is not safe in single line if / else or for /which blocks, however working around this results in checkpatch producing invalid warnings, as reported by Shuah. * Fixing these macros is out of scope for this series, so compromise and instead rewrite test blocks so as to use multiple lines by separating out a decl in most cases. This has the side effect of, for the most part, making things more readable. * Heavily document the use of the volatile keyword - we can't avoid checkpatch complaining about this, so we explain it, as reported by Shuah. * Updated commit message to highlight that we skip tests we lack permissions for, as reported by Shuah. * Replaced a perror() with ksft_exit_fail_perror(), as reported by Shuah. * Added user friendly messages to cases where tests are skipped due to lack of permissions, as reported by Shuah. * Update the tool header to include the new MADV_GUARD_POISON/UNPOISON defines and directly include asm-generic/mman.h to get the platform-neutral versions to ensure we import them. * Finally fixed Vlastimil's email address in Suggested-by tags from suze to suse, as reported by Vlastimil. * Added linux-api to cc list, as reported by Vlastimil. v1 * Un-RFC'd as appears no major objections to approach but rather debate on implementation. * Fixed issue with arches which need mmu_context.h and tlbfush.h. header imports in pagewalker logic to be able to use update_mmu_cache() as reported by the kernel test bot. * Added comments in page walker logic to clarify who can use ops->install_pte and why as well as adding a check_ops_valid() helper function, as suggested by Christoph. * Pass false in full parameter in pte_clear_not_present_full() as suggested by Jann. * Stopped erroneously requiring a write lock for the poison operation as suggested by Jann and Suren. * Moved anon_vma_prepare() to the start of madvise_guard_poison() to be consistent with how this is used elsewhere in the kernel as suggested by Jann. * Avoid returning -EAGAIN if we are raced on page faults, just keep looping and duck out if a fatal signal is pending or a conditional reschedule is needed, as suggested by Jann. * Avoid needlessly splitting huge PUDs and PMDs by specifying ACTION_CONTINUE, as suggested by Jann. https://lore.kernel.org/all/cover.1729196871.git.lorenzo.stoakes@oracle.com/ RFC https://lore.kernel.org/all/cover.1727440966.git.lorenzo.stoakes@oracle.com/ Lorenzo Stoakes (5): mm: pagewalk: add the ability to install PTEs mm: add PTE_MARKER_GUARD PTE marker mm: madvise: implement lightweight guard page mechanism tools: testing: update tools UAPI header for mman-common.h selftests/mm: add self tests for guard page feature arch/alpha/include/uapi/asm/mman.h | 3 + arch/mips/include/uapi/asm/mman.h | 3 + arch/parisc/include/uapi/asm/mman.h | 3 + arch/xtensa/include/uapi/asm/mman.h | 3 + include/linux/mm_inline.h | 2 +- include/linux/pagewalk.h | 18 +- include/linux/swapops.h | 26 +- include/uapi/asm-generic/mman-common.h | 3 + mm/hugetlb.c | 3 + mm/internal.h | 6 + mm/madvise.c | 168 +++ mm/memory.c | 18 +- mm/mprotect.c | 3 +- mm/mseal.c | 1 + mm/pagewalk.c | 200 ++- tools/include/uapi/asm-generic/mman-common.h | 3 + tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/guard-pages.c | 1228 ++++++++++++++++++ 19 files changed, 1627 insertions(+), 66 deletions(-) create mode 100644 tools/testing/selftests/mm/guard-pages.c -- 2.47.0

1 year, 2 months

10
65
0 0

[PATCH] kselftest/arm64: Log fp-stress child startup errors to stdout

by Mark Brown

Currently if we encounter an error between fork() and exec() of a child process we log the error to stderr. This means that the errors don't get annotated with the child information which makes diagnostics harder and means that if we miss the exit signal from the child we can deadlock waiting for output from the child. Improve robustness and output quality by logging to stdout instead. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/arm64/fp/fp-stress.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/arm64/fp/fp-stress.c b/tools/testing/selftests/arm64/fp/fp-stress.c index faac24bdefeb9436e2daf20b7250d0ae25ca23a7..80f22789504d661efc52a90d4b0893fbebec42f8 100644 --- a/tools/testing/selftests/arm64/fp/fp-stress.c +++ b/tools/testing/selftests/arm64/fp/fp-stress.c @@ -79,7 +79,7 @@ static void child_start(struct child_data *child, const char *program) */ ret = dup2(pipefd[1], 1); if (ret == -1) { - fprintf(stderr, "dup2() %d\n", errno); + printf("dup2() %d\n", errno); exit(EXIT_FAILURE); } @@ -89,7 +89,7 @@ static void child_start(struct child_data *child, const char *program) */ ret = dup2(startup_pipe[0], 3); if (ret == -1) { - fprintf(stderr, "dup2() %d\n", errno); + printf("dup2() %d\n", errno); exit(EXIT_FAILURE); } @@ -107,16 +107,15 @@ static void child_start(struct child_data *child, const char *program) */ ret = read(3, &i, sizeof(i)); if (ret < 0) - fprintf(stderr, "read(startp pipe) failed: %s (%d)\n", - strerror(errno), errno); + printf("read(startp pipe) failed: %s (%d)\n", + strerror(errno), errno); if (ret > 0) - fprintf(stderr, "%d bytes of data on startup pipe\n", - ret); + printf("%d bytes of data on startup pipe\n", ret); close(3); ret = execl(program, program, NULL); - fprintf(stderr, "execl(%s) failed: %d (%s)\n", - program, errno, strerror(errno)); + printf("execl(%s) failed: %d (%s)\n", + program, errno, strerror(errno)); exit(EXIT_FAILURE); } else { --- base-commit: 8e929cb546ee42c9a61d24fae60605e9e3192354 change-id: 20241017-arm64-fp-stress-exec-fail-d074ec82cf43 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 year, 2 months

2
1
0 0

[PATCH bpf-next v2 0/4] Retire test_sock.c

by Jordan Rife

This patch series migrates test cases out of test_sock.c to prog_tests-style tests. It moves all BPF_CGROUP_INET4_POST_BIND and BPF_CGROUP_INET6_POST_BIND test cases into a new prog_test, sock_post_bind.c, while reimplementing all LOAD_REJECT test cases as verifier tests in progs/verifier_sock.c. Finally, it moves remaining BPF_CGROUP_INET_SOCK_CREATE test coverage into prog_tests/sock_create.c before retiring test_sock.c completely. Changes ======= v1->v2: - Remove superfluous verbose bool from the top of sock_post_bind.c. - Use ASSERT_OK_FD instead of ASSERT_GE to test cgroup_fd validity. - Run sock_post_bind tests in their own namespace, "sock_post_bind". Jordan Rife (4): selftests/bpf: Migrate *_POST_BIND test cases to prog_tests selftests/bpf: Migrate LOAD_REJECT test cases to prog_tests selftests/bpf: Migrate BPF_CGROUP_INET_SOCK_CREATE test cases to prog_tests selftests/bpf: Retire test_sock.c tools/testing/selftests/bpf/.gitignore | 1 - tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/sock_create.c | 35 ++- .../sock_post_bind.c} | 256 +++++------------- .../selftests/bpf/progs/verifier_sock.c | 60 ++++ 5 files changed, 150 insertions(+), 205 deletions(-) rename tools/testing/selftests/bpf/{test_sock.c => prog_tests/sock_post_bind.c} (64%) -- 2.47.0.105.g07ac214952-goog

1 year, 2 months

2
5
0 0

[PATCH 1/2] selftests/intel_pstate: fix operand expected

by Alessandro Zanni

Running "make kselftest TARGETS=intel_pstate" results in the following errors: - ./run.sh: line 90: / 1000: syntax error: operand expected (error token is "/ 1000") - ./run.sh: line 92: / 1000: syntax error: operand expected (error token is "/ 1000") This fix allows to have cross-platform compatibility when using arithmetic expression with command substitutions. Signed-off-by: Alessandro Zanni <alessandro.zanni87(a)gmail.com> --- tools/testing/selftests/intel_pstate/run.sh | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/intel_pstate/run.sh b/tools/testing/selftests/intel_pstate/run.sh index e7008f614ad7..0c1b6c1308a4 100755 --- a/tools/testing/selftests/intel_pstate/run.sh +++ b/tools/testing/selftests/intel_pstate/run.sh @@ -87,9 +87,9 @@ mkt_freq=${_mkt_freq}0 # Get the ranges from cpupower _min_freq=$(cpupower frequency-info -l | tail -1 | awk ' { print $1 } ') -min_freq=$(($_min_freq / 1000)) +min_freq=$((_min_freq / 1000)) _max_freq=$(cpupower frequency-info -l | tail -1 | awk ' { print $2 } ') -max_freq=$(($_max_freq / 1000)) +max_freq=$((_max_freq / 1000)) [ $EVALUATE_ONLY -eq 0 ] && for freq in `seq $max_freq -100 $min_freq` -- 2.43.0 From d6500cf7c800bd39ae3ef2930cece5b3be460c0b Mon Sep 17 00:00:00 2001 From: Alessandro Zanni <alessandro.zanni87(a)gmail.com> Date: Tue, 22 Oct 2024 17:22:13 +0200 Subject: [PATCH 2/2] selftests/intel_pstate: cpupower command not found To: shuah(a)kernel.org Cc: linux-kselftest(a)vger.kernel.org, linux-kernel(a)vger.kernel.org, skhan(a)linuxfoundation.org, anupnewsmail(a)gmail.com Running "make kselftest TARGETS=intel_pstate" results in the following errors: - ./run.sh: line 89: cpupower: command not found - ./run.sh: line 91: cpupower: command not found if the cpupower is not installed. Since the test depends on cpupower, this patch stops the test if the cpupower is not installed. Signed-off-by: Alessandro Zanni <alessandro.zanni87(a)gmail.com> --- tools/testing/selftests/intel_pstate/run.sh | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/testing/selftests/intel_pstate/run.sh b/tools/testing/selftests/intel_pstate/run.sh index 0c1b6c1308a4..6a3b8503264e 100755 --- a/tools/testing/selftests/intel_pstate/run.sh +++ b/tools/testing/selftests/intel_pstate/run.sh @@ -44,6 +44,11 @@ if [ $UID != 0 ] && [ $EVALUATE_ONLY == 0 ]; then exit $ksft_skip fi +if ! command -v cpupower &> /dev/null; then + echo $msg cpupower could not be found, please install it >&2 + exit $ksft_skip +fi + max_cpus=$(($(nproc)-1)) function run_test () { -- 2.43.0

1 year, 2 months

1
0
0 0

[PATCH] selftests/sched: add basic test for psi

by Pintu Kumar

There is a psi module that exists under kernel/sched/psi. Add a basic test to test the psi. This test just add the basic support to check cpu/memory/io interface. Further test will be added on top of this. Signed-off-by: Pintu Kumar <quic_pintu(a)quicinc.com> --- MAINTAINERS | 2 + tools/testing/selftests/sched/.gitignore | 1 + tools/testing/selftests/sched/Makefile | 4 +- tools/testing/selftests/sched/config | 1 + tools/testing/selftests/sched/psi_test.c | 85 ++++++++++++++++++++++++ tools/testing/selftests/sched/run_psi.sh | 36 ++++++++++ 6 files changed, 127 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/sched/psi_test.c create mode 100755 tools/testing/selftests/sched/run_psi.sh diff --git a/MAINTAINERS b/MAINTAINERS index 84a73e90cfe8..d84ff9ca36a9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18548,10 +18548,12 @@ F: include/uapi/linux/pps.h PRESSURE STALL INFORMATION (PSI) M: Johannes Weiner <hannes(a)cmpxchg.org> M: Suren Baghdasaryan <surenb(a)google.com> +M: Pintu Kumar <quic_pintu(a)quicinc.com> R: Peter Ziljstra <peterz(a)infradead.org> S: Maintained F: include/linux/psi* F: kernel/sched/psi.c +F: tools/testing/selftests/sched/psi_test.c PRINTK M: Petr Mladek <pmladek(a)suse.com> diff --git a/tools/testing/selftests/sched/.gitignore b/tools/testing/selftests/sched/.gitignore index 6996d4654d92..2b15c11b93e6 100644 --- a/tools/testing/selftests/sched/.gitignore +++ b/tools/testing/selftests/sched/.gitignore @@ -1 +1,2 @@ cs_prctl_test +psi_test diff --git a/tools/testing/selftests/sched/Makefile b/tools/testing/selftests/sched/Makefile index 099ee9213557..795f6613eb2c 100644 --- a/tools/testing/selftests/sched/Makefile +++ b/tools/testing/selftests/sched/Makefile @@ -8,7 +8,7 @@ CFLAGS += -O2 -Wall -g -I./ $(KHDR_INCLUDES) -Wl,-rpath=./ \ $(CLANG_FLAGS) LDLIBS += -lpthread -TEST_GEN_FILES := cs_prctl_test -TEST_PROGS := cs_prctl_test +TEST_GEN_FILES := cs_prctl_test psi_test +TEST_PROGS := cs_prctl_test run_psi.sh include ../lib.mk diff --git a/tools/testing/selftests/sched/config b/tools/testing/selftests/sched/config index e8b09aa7c0c4..287cccd434fd 100644 --- a/tools/testing/selftests/sched/config +++ b/tools/testing/selftests/sched/config @@ -1 +1,2 @@ CONFIG_SCHED_DEBUG=y +CONFIG_PSI=y diff --git a/tools/testing/selftests/sched/psi_test.c b/tools/testing/selftests/sched/psi_test.c new file mode 100644 index 000000000000..eeba138d2b39 --- /dev/null +++ b/tools/testing/selftests/sched/psi_test.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <stdio.h> +#include <string.h> +#include <fcntl.h> + + +struct load_avg { + float avg10; + float avg60; + float avg300; + unsigned long long total; +}; + +struct pressure { + struct load_avg some; + struct load_avg full; +}; + + +int psi_get_data_from_proc_pressure(const char *path, struct pressure *p) +{ + FILE *fp; + int rc = -1; + int ret = 0; + + if (path == NULL || p == NULL) + return -1; + + fp = fopen(path, "r"); + if (fp == NULL) + return -1; + + while (!feof(fp)) { + rc = fscanf(fp, "some avg10=%f avg60=%f avg300=%f total=%llu\n", + &p->some.avg10, &p->some.avg60, &p->some.avg300, &p->some.total); + if (rc < 1) { + ret = -1; + break; + } + + /* Note: In some cases (cpu) full may not exists */ + rc = fscanf(fp, "full avg10=%f avg60=%f avg300=%f total=%llu\n", + &p->full.avg10, &p->full.avg60, &p->full.avg300, &p->full.total); + /* We don't care about full case. This is needed to avoid warnings */ + rc = 0; + } + + fclose(fp); + + return ret; +} + +int main(int argc, char *argv[]) +{ + int ret; + struct pressure rs = {0,}; + char path[32]; + + if (argc < 2) { + fprintf(stderr, "usage: %s <path>\n", argv[0]); + return -1; + } + + memset(&rs, 0, sizeof(rs)); + printf("Pressure data: %s\n", argv[1]); + snprintf(path, sizeof(path)-1, "/proc/pressure/%s", argv[1]); + + ret = psi_get_data_from_proc_pressure(path, &rs); + if (ret < 0) { + printf("PSI <%s>: FAIL\n", argv[1]); + return -1; + } + printf("Some Avg10 = %5.2f\n", rs.some.avg10); + printf("Some Avg60 = %5.2f\n", rs.some.avg60); + printf("Some Avg300 = %5.2f\n", rs.some.avg300); + printf("Some Total = %llu\n", rs.some.total); + printf("Full Avg10 = %5.2f\n", rs.full.avg10); + printf("Full Avg60 = %5.2f\n", rs.full.avg60); + printf("Full Avg300 = %5.2f\n", rs.full.avg300); + printf("Full Total = %llu\n", rs.full.total); + + + return 0; +} diff --git a/tools/testing/selftests/sched/run_psi.sh b/tools/testing/selftests/sched/run_psi.sh new file mode 100755 index 000000000000..d0b1c7ae3736 --- /dev/null +++ b/tools/testing/selftests/sched/run_psi.sh @@ -0,0 +1,36 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 + +# Just one node check is enough to detect psi +if [ ! -e /proc/pressure/cpu ]; then + echo "PSI not present..." + exit $ksft_skip +fi + +echo "" +./psi_test cpu +if [ $? -ne 0 ]; then + echo "CPU - [FAIL]" +else + echo "CPU - [PASS]" +fi + +echo "" +./psi_test memory +if [ $? -ne 0 ]; then + echo "MEMORY - [FAIL]" +else + echo "MEMORY - [PASS]" +fi + +echo "" +./psi_test io +if [ $? -ne 0 ]; then + echo "IO - [FAIL]" +else + echo "IO - [PASS]" +fi -- 2.17.1

1 year, 2 months

3
2
0 0

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