From 9940d67c93b5bb7ddcf862b41b1847cb728186c4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 6 Apr 2016 18:43:27 -0700 Subject: [PATCH] bpf: support bpf_get_stackid() and bpf_perf_event_output() in tracepoint programs needs two wrapper functions to fetch 'struct pt_regs *' to convert tracepoint bpf context into kprobe bpf context to reuse existing helper functions Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/bpf.h | 1 + kernel/bpf/stackmap.c | 2 +- kernel/trace/bpf_trace.c | 42 +++++++++++++++++++++++++++++++++++++++++- 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 21ee41b..198f6ac 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -160,6 +160,7 @@ struct bpf_array { #define MAX_TAIL_CALL_CNT 32 u64 bpf_tail_call(u64 ctx, u64 r2, u64 index, u64 r4, u64 r5); +u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); void bpf_fd_array_map_clear(struct bpf_map *map); bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp); const struct bpf_func_proto *bpf_get_trace_printk_proto(void); diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 499d9e9..3511472 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -116,7 +116,7 @@ free_smap: return ERR_PTR(err); } -static u64 bpf_get_stackid(u64 r1, u64 r2, u64 flags, u64 r4, u64 r5) +u64 bpf_get_stackid(u64 r1, u64 r2, u64 flags, u64 r4, u64 r5) { struct pt_regs *regs = (struct pt_regs *) (long) r1; struct bpf_map *map = (struct bpf_map *) (long) r2; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3e5ebe3..413ec56 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -340,12 +340,52 @@ static struct bpf_prog_type_list kprobe_tl = { .type = BPF_PROG_TYPE_KPROBE, }; +static u64 bpf_perf_event_output_tp(u64 r1, u64 r2, u64 index, u64 r4, u64 size) +{ + /* + * r1 points to perf tracepoint buffer where first 8 bytes are hidden + * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it + * from there and call the same bpf_perf_event_output() helper + */ + u64 ctx = *(long *)r1; + + return bpf_perf_event_output(ctx, r2, index, r4, size); +} + +static const struct bpf_func_proto bpf_perf_event_output_proto_tp = { + .func = bpf_perf_event_output_tp, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_STACK, + .arg5_type = ARG_CONST_STACK_SIZE, +}; + +static u64 bpf_get_stackid_tp(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + u64 ctx = *(long *)r1; + + return bpf_get_stackid(ctx, r2, r3, r4, r5); +} + +static const struct bpf_func_proto bpf_get_stackid_proto_tp = { + .func = bpf_get_stackid_tp, + .gpl_only = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_CONST_MAP_PTR, + .arg3_type = ARG_ANYTHING, +}; + static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id) { switch (func_id) { case BPF_FUNC_perf_event_output: + return &bpf_perf_event_output_proto_tp; case BPF_FUNC_get_stackid: - return NULL; + return &bpf_get_stackid_proto_tp; default: return tracing_func_proto(func_id); } -- 2.7.4