From 6816a7ffce32e999601825ddfd887f36d3052932 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 28 Jun 2016 12:18:25 +0200 Subject: [PATCH] bpf, trace: add BPF_F_CURRENT_CPU flag for bpf_perf_event_read Follow-up commit to 1e33759c788c ("bpf, trace: add BPF_F_CURRENT_CPU flag for bpf_perf_event_output") to add the same functionality into bpf_perf_event_read() helper. The split of index into flags and index component is also safe here, since such large maps are rejected during map allocation time. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 2 +- kernel/trace/bpf_trace.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 406459b935a2..58df2da3e9bf 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -347,7 +347,7 @@ enum bpf_func_id { #define BPF_F_ZERO_CSUM_TX (1ULL << 1) #define BPF_F_DONT_FRAGMENT (1ULL << 2) -/* BPF_FUNC_perf_event_output flags. */ +/* BPF_FUNC_perf_event_output and BPF_FUNC_perf_event_read flags. */ #define BPF_F_INDEX_MASK 0xffffffffULL #define BPF_F_CURRENT_CPU BPF_F_INDEX_MASK diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 505f9e9cdb3b..19c5b4a5c3eb 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -188,13 +188,19 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void) return &bpf_trace_printk_proto; } -static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) +static u64 bpf_perf_event_read(u64 r1, u64 flags, u64 r3, u64 r4, u64 r5) { struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; struct bpf_array *array = container_of(map, struct bpf_array, map); + unsigned int cpu = smp_processor_id(); + u64 index = flags & BPF_F_INDEX_MASK; struct bpf_event_entry *ee; struct perf_event *event; + if (unlikely(flags & ~(BPF_F_INDEX_MASK))) + return -EINVAL; + if (index == BPF_F_CURRENT_CPU) + index = cpu; if (unlikely(index >= array->map.max_entries)) return -E2BIG; @@ -208,8 +214,7 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) return -EINVAL; /* make sure event is local and doesn't have pmu::count */ - if (event->oncpu != smp_processor_id() || - event->pmu->count) + if (unlikely(event->oncpu != cpu || event->pmu->count)) return -EINVAL; /*