diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 21:37:47 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 21:37:47 (GMT) |
commit | 6c8a53c9e6a151fffb07f8b4c34bd1e33dddd467 (patch) | |
tree | 791caf826ef136c521a97b7878f226b6ba1c1d75 /kernel/trace | |
parent | e95e7f627062be5e6ce971ce873e6234c91ffc50 (diff) | |
parent | 066450be419fa48007a9f29e19828f2a86198754 (diff) | |
download | linux-6c8a53c9e6a151fffb07f8b4c34bd1e33dddd467.tar.xz |
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf changes from Ingo Molnar:
"Core kernel changes:
- One of the more interesting features in this cycle is the ability
to attach eBPF programs (user-defined, sandboxed bytecode executed
by the kernel) to kprobes.
This allows user-defined instrumentation on a live kernel image
that can never crash, hang or interfere with the kernel negatively.
(Right now it's limited to root-only, but in the future we might
allow unprivileged use as well.)
(Alexei Starovoitov)
- Another non-trivial feature is per event clockid support: this
allows, amongst other things, the selection of different clock
sources for event timestamps traced via perf.
This feature is sought by people who'd like to merge perf generated
events with external events that were measured with different
clocks:
- cluster wide profiling
- for system wide tracing with user-space events,
- JIT profiling events
etc. Matching perf tooling support is added as well, available via
the -k, --clockid <clockid> parameter to perf record et al.
(Peter Zijlstra)
Hardware enablement kernel changes:
- x86 Intel Processor Trace (PT) support: which is a hardware tracer
on steroids, available on Broadwell CPUs.
The hardware trace stream is directly output into the user-space
ring-buffer, using the 'AUX' data format extension that was added
to the perf core to support hardware constraints such as the
necessity to have the tracing buffer physically contiguous.
This patch-set was developed for two years and this is the result.
A simple way to make use of this is to use BTS tracing, the PT
driver emulates BTS output - available via the 'intel_bts' PMU.
More explicit PT specific tooling support is in the works as well -
will probably be ready by 4.2.
(Alexander Shishkin, Peter Zijlstra)
- x86 Intel Cache QoS Monitoring (CQM) support: this is a hardware
feature of Intel Xeon CPUs that allows the measurement and
allocation/partitioning of caches to individual workloads.
These kernel changes expose the measurement side as a new PMU
driver, which exposes various QoS related PMU events. (The
partitioning change is work in progress and is planned to be merged
as a cgroup extension.)
(Matt Fleming, Peter Zijlstra; CPU feature detection by Peter P
Waskiewicz Jr)
- x86 Intel Haswell LBR call stack support: this is a new Haswell
feature that allows the hardware recording of call chains, plus
tooling support. To activate this feature you have to enable it
via the new 'lbr' call-graph recording option:
perf record --call-graph lbr
perf report
or:
perf top --call-graph lbr
This hardware feature is a lot faster than stack walk or dwarf
based unwinding, but has some limitations:
- It reuses the current LBR facility, so LBR call stack and
branch record can not be enabled at the same time.
- It is only available for user-space callchains.
(Yan, Zheng)
- x86 Intel Broadwell CPU support and various event constraints and
event table fixes for earlier models.
(Andi Kleen)
- x86 Intel HT CPUs event scheduling workarounds. This is a complex
CPU bug affecting the SNB,IVB,HSW families that results in counter
value corruption. The mitigation code is automatically enabled and
is transparent.
(Maria Dimakopoulou, Stephane Eranian)
The perf tooling side had a ton of changes in this cycle as well, so
I'm only able to list the user visible changes here, in addition to
the tooling changes outlined above:
User visible changes affecting all tools:
- Improve support of compressed kernel modules (Jiri Olsa)
- Save DSO loading errno to better report errors (Arnaldo Carvalho de Melo)
- Bash completion for subcommands (Yunlong Song)
- Add 'I' event modifier for perf_event_attr.exclude_idle bit (Jiri Olsa)
- Support missing -f to override perf.data file ownership. (Yunlong Song)
- Show the first event with an invalid filter (David Ahern, Arnaldo Carvalho de Melo)
User visible changes in individual tools:
'perf data':
New tool for converting perf.data to other formats, initially
for the CTF (Common Trace Format) from LTTng (Jiri Olsa,
Sebastian Siewior)
'perf diff':
Add --kallsyms option (David Ahern)
'perf list':
Allow listing events with 'tracepoint' prefix (Yunlong Song)
Sort the output of the command (Yunlong Song)
'perf kmem':
Respect -i option (Jiri Olsa)
Print big numbers using thousands' group (Namhyung Kim)
Allow -v option (Namhyung Kim)
Fix alignment of slab result table (Namhyung Kim)
'perf probe':
Support multiple probes on different binaries on the same command line (Masami Hiramatsu)
Support unnamed union/structure members data collection. (Masami Hiramatsu)
Check kprobes blacklist when adding new events. (Masami Hiramatsu)
'perf record':
Teach 'perf record' about perf_event_attr.clockid (Peter Zijlstra)
Support recording running/enabled time (Andi Kleen)
'perf sched':
Improve the performance of 'perf sched replay' on high CPU core count machines (Yunlong Song)
'perf report' and 'perf top':
Allow annotating entries in callchains in the hists browser (Arnaldo Carvalho de Melo)
Indicate which callchain entries are annotated in the
TUI hists browser (Arnaldo Carvalho de Melo)
Add pid/tid filtering to 'report' and 'script' commands (David Ahern)
Consider PERF_RECORD_ events with cpumode == 0 in 'perf top', removing one
cause of long term memory usage buildup, i.e. not processing PERF_RECORD_EXIT
events (Arnaldo Carvalho de Melo)
'perf stat':
Report unsupported events properly (Suzuki K. Poulose)
Output running time and run/enabled ratio in CSV mode (Andi Kleen)
'perf trace':
Handle legacy syscalls tracepoints (David Ahern, Arnaldo Carvalho de Melo)
Only insert blank duration bracket when tracing syscalls (Arnaldo Carvalho de Melo)
Filter out the trace pid when no threads are specified (Arnaldo Carvalho de Melo)
Dump stack on segfaults (Arnaldo Carvalho de Melo)
No need to explicitely enable evsels for workload started from perf, let it
be enabled via perf_event_attr.enable_on_exec, removing some events that take
place in the 'perf trace' before a workload is really started by it.
(Arnaldo Carvalho de Melo)
Allow mixing with tracepoints and suppressing plain syscalls. (Arnaldo Carvalho de Melo)
There's also been a ton of infrastructure work done, such as the
split-out of perf's build system into tools/build/ and other changes -
see the shortlog and changelog for details"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (358 commits)
perf/x86/intel/pt: Clean up the control flow in pt_pmu_hw_init()
perf evlist: Fix type for references to data_head/tail
perf probe: Check the orphaned -x option
perf probe: Support multiple probes on different binaries
perf buildid-list: Fix segfault when show DSOs with hits
perf tools: Fix cross-endian analysis
perf tools: Fix error path to do closedir() when synthesizing threads
perf tools: Fix synthesizing fork_event.ppid for non-main thread
perf tools: Add 'I' event modifier for exclude_idle bit
perf report: Don't call map__kmap if map is NULL.
perf tests: Fix attr tests
perf probe: Fix ARM 32 building error
perf tools: Merge all perf_event_attr print functions
perf record: Add clockid parameter
perf sched replay: Use replay_repeat to calculate the runavg of cpu usage instead of the default value 10
perf sched replay: Support using -f to override perf.data file ownership
perf sched replay: Fix the EMFILE error caused by the limitation of the maximum open files
perf sched replay: Handle the dead halt of sem_wait when create_tasks() fails for any task
perf sched replay: Fix the segmentation fault problem caused by pr_err in threads
perf sched replay: Realloc the memory of pid_to_task stepwise to adapt to the different pid_max configurations
...
Diffstat (limited to 'kernel/trace')
-rw-r--r-- | kernel/trace/Kconfig | 8 | ||||
-rw-r--r-- | kernel/trace/Makefile | 1 | ||||
-rw-r--r-- | kernel/trace/bpf_trace.c | 222 | ||||
-rw-r--r-- | kernel/trace/trace_kprobe.c | 10 | ||||
-rw-r--r-- | kernel/trace/trace_uprobe.c | 10 |
5 files changed, 245 insertions, 6 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index fedbdd7..3b9a48a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -432,6 +432,14 @@ config UPROBE_EVENT This option is required if you plan to use perf-probe subcommand of perf tools on user space applications. +config BPF_EVENTS + depends on BPF_SYSCALL + depends on KPROBE_EVENT + bool + default y + help + This allows the user to attach BPF programs to kprobe events. + config PROBE_EVENTS def_bool n diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 98f2658..9b1044e 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -53,6 +53,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o endif obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o +obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o obj-$(CONFIG_TRACEPOINTS) += power-traces.o ifeq ($(CONFIG_PM),y) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c new file mode 100644 index 0000000..2d56ce5 --- /dev/null +++ b/kernel/trace/bpf_trace.c @@ -0,0 +1,222 @@ +/* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/bpf.h> +#include <linux/filter.h> +#include <linux/uaccess.h> +#include <linux/ctype.h> +#include "trace.h" + +static DEFINE_PER_CPU(int, bpf_prog_active); + +/** + * trace_call_bpf - invoke BPF program + * @prog: BPF program + * @ctx: opaque context pointer + * + * kprobe handlers execute BPF programs via this helper. + * Can be used from static tracepoints in the future. + * + * Return: BPF programs always return an integer which is interpreted by + * kprobe handler as: + * 0 - return from kprobe (event is filtered out) + * 1 - store kprobe event into ring buffer + * Other values are reserved and currently alias to 1 + */ +unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx) +{ + unsigned int ret; + + if (in_nmi()) /* not supported yet */ + return 1; + + preempt_disable(); + + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { + /* + * since some bpf program is already running on this cpu, + * don't call into another bpf program (same or different) + * and don't send kprobe event into ring-buffer, + * so return zero here + */ + ret = 0; + goto out; + } + + rcu_read_lock(); + ret = BPF_PROG_RUN(prog, ctx); + rcu_read_unlock(); + + out: + __this_cpu_dec(bpf_prog_active); + preempt_enable(); + + return ret; +} +EXPORT_SYMBOL_GPL(trace_call_bpf); + +static u64 bpf_probe_read(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + void *dst = (void *) (long) r1; + int size = (int) r2; + void *unsafe_ptr = (void *) (long) r3; + + return probe_kernel_read(dst, unsafe_ptr, size); +} + +static const struct bpf_func_proto bpf_probe_read_proto = { + .func = bpf_probe_read, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_STACK, + .arg2_type = ARG_CONST_STACK_SIZE, + .arg3_type = ARG_ANYTHING, +}; + +static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + /* NMI safe access to clock monotonic */ + return ktime_get_mono_fast_ns(); +} + +static const struct bpf_func_proto bpf_ktime_get_ns_proto = { + .func = bpf_ktime_get_ns, + .gpl_only = true, + .ret_type = RET_INTEGER, +}; + +/* + * limited trace_printk() + * only %d %u %x %ld %lu %lx %lld %llu %llx %p conversion specifiers allowed + */ +static u64 bpf_trace_printk(u64 r1, u64 fmt_size, u64 r3, u64 r4, u64 r5) +{ + char *fmt = (char *) (long) r1; + int mod[3] = {}; + int fmt_cnt = 0; + int i; + + /* + * bpf_check()->check_func_arg()->check_stack_boundary() + * guarantees that fmt points to bpf program stack, + * fmt_size bytes of it were initialized and fmt_size > 0 + */ + if (fmt[--fmt_size] != 0) + return -EINVAL; + + /* check format string for allowed specifiers */ + for (i = 0; i < fmt_size; i++) { + if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) + return -EINVAL; + + if (fmt[i] != '%') + continue; + + if (fmt_cnt >= 3) + return -EINVAL; + + /* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */ + i++; + if (fmt[i] == 'l') { + mod[fmt_cnt]++; + i++; + } else if (fmt[i] == 'p') { + mod[fmt_cnt]++; + i++; + if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0) + return -EINVAL; + fmt_cnt++; + continue; + } + + if (fmt[i] == 'l') { + mod[fmt_cnt]++; + i++; + } + + if (fmt[i] != 'd' && fmt[i] != 'u' && fmt[i] != 'x') + return -EINVAL; + fmt_cnt++; + } + + return __trace_printk(1/* fake ip will not be printed */, fmt, + mod[0] == 2 ? r3 : mod[0] == 1 ? (long) r3 : (u32) r3, + mod[1] == 2 ? r4 : mod[1] == 1 ? (long) r4 : (u32) r4, + mod[2] == 2 ? r5 : mod[2] == 1 ? (long) r5 : (u32) r5); +} + +static const struct bpf_func_proto bpf_trace_printk_proto = { + .func = bpf_trace_printk, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_STACK, + .arg2_type = ARG_CONST_STACK_SIZE, +}; + +static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id) +{ + switch (func_id) { + case BPF_FUNC_map_lookup_elem: + return &bpf_map_lookup_elem_proto; + case BPF_FUNC_map_update_elem: + return &bpf_map_update_elem_proto; + case BPF_FUNC_map_delete_elem: + return &bpf_map_delete_elem_proto; + case BPF_FUNC_probe_read: + return &bpf_probe_read_proto; + case BPF_FUNC_ktime_get_ns: + return &bpf_ktime_get_ns_proto; + + case BPF_FUNC_trace_printk: + /* + * this program might be calling bpf_trace_printk, + * so allocate per-cpu printk buffers + */ + trace_printk_init_buffers(); + + return &bpf_trace_printk_proto; + default: + return NULL; + } +} + +/* bpf+kprobe programs can access fields of 'struct pt_regs' */ +static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type) +{ + /* check bounds */ + if (off < 0 || off >= sizeof(struct pt_regs)) + return false; + + /* only read is allowed */ + if (type != BPF_READ) + return false; + + /* disallow misaligned access */ + if (off % size != 0) + return false; + + return true; +} + +static struct bpf_verifier_ops kprobe_prog_ops = { + .get_func_proto = kprobe_prog_func_proto, + .is_valid_access = kprobe_prog_is_valid_access, +}; + +static struct bpf_prog_type_list kprobe_tl = { + .ops = &kprobe_prog_ops, + .type = BPF_PROG_TYPE_KPROBE, +}; + +static int __init register_kprobe_prog_ops(void) +{ + bpf_register_prog_type(&kprobe_tl); + return 0; +} +late_initcall(register_kprobe_prog_ops); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 9ba3f43..d0ce590 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1135,11 +1135,15 @@ static void kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) { struct ftrace_event_call *call = &tk->tp.call; + struct bpf_prog *prog = call->prog; struct kprobe_trace_entry_head *entry; struct hlist_head *head; int size, __size, dsize; int rctx; + if (prog && !trace_call_bpf(prog, regs)) + return; + head = this_cpu_ptr(call->perf_events); if (hlist_empty(head)) return; @@ -1166,11 +1170,15 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, struct pt_regs *regs) { struct ftrace_event_call *call = &tk->tp.call; + struct bpf_prog *prog = call->prog; struct kretprobe_trace_entry_head *entry; struct hlist_head *head; int size, __size, dsize; int rctx; + if (prog && !trace_call_bpf(prog, regs)) + return; + head = this_cpu_ptr(call->perf_events); if (hlist_empty(head)) return; @@ -1287,7 +1295,7 @@ static int register_kprobe_event(struct trace_kprobe *tk) kfree(call->print_fmt); return -ENODEV; } - call->flags = 0; + call->flags = TRACE_EVENT_FL_KPROBE; call->class->reg = kprobe_register; call->data = tk; ret = trace_add_event_call(call); diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 7486546..d60fe62 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1006,7 +1006,7 @@ __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) return true; list_for_each_entry(event, &filter->perf_events, hw.tp_list) { - if (event->hw.tp_target->mm == mm) + if (event->hw.target->mm == mm) return true; } @@ -1016,7 +1016,7 @@ __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) static inline bool uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) { - return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm); + return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); } static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) @@ -1024,10 +1024,10 @@ static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) bool done; write_lock(&tu->filter.rwlock); - if (event->hw.tp_target) { + if (event->hw.target) { list_del(&event->hw.tp_list); done = tu->filter.nr_systemwide || - (event->hw.tp_target->flags & PF_EXITING) || + (event->hw.target->flags & PF_EXITING) || uprobe_filter_event(tu, event); } else { tu->filter.nr_systemwide--; @@ -1047,7 +1047,7 @@ static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) int err; write_lock(&tu->filter.rwlock); - if (event->hw.tp_target) { + if (event->hw.target) { /* * event->parent != NULL means copy_process(), we can avoid * uprobe_apply(). current->mm must be probed and we can rely |