From 67306f84ca78c2ca5136f21791710c126a55a19b Mon Sep 17 00:00:00 2001 From: Daniel Xu Date: Mon, 17 Feb 2020 19:04:32 -0800 Subject: selftests/bpf: Add bpf_read_branch_records() selftest Add a selftest to test: * default bpf_read_branch_records() behavior * BPF_F_GET_BRANCH_RECORDS_SIZE flag behavior * error path on non branch record perf events * using helper to write to stack * using helper to write to global On host with hardware counter support: # ./test_progs -t perf_branches #27/1 perf_branches_hw:OK #27/2 perf_branches_no_hw:OK #27 perf_branches:OK Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED On host without hardware counter support (VM): # ./test_progs -t perf_branches #27/1 perf_branches_hw:OK #27/2 perf_branches_no_hw:OK #27 perf_branches:OK Summary: 1/2 PASSED, 1 SKIPPED, 0 FAILED Also sync tools/include/uapi/linux/bpf.h. Signed-off-by: Daniel Xu Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200218030432.4600-3-dxu@dxuuu.xyz --- tools/include/uapi/linux/bpf.h | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'tools/include') diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index f1d74a2bd234..a7e59756853f 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2892,6 +2892,25 @@ union bpf_attr { * Obtain the 64bit jiffies * Return * The 64 bit jiffies + * + * int bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags) + * Description + * For an eBPF program attached to a perf event, retrieve the + * branch records (struct perf_branch_entry) associated to *ctx* + * and store it in the buffer pointed by *buf* up to size + * *size* bytes. + * Return + * On success, number of bytes written to *buf*. On error, a + * negative value. + * + * The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to + * instead return the number of bytes required to store all the + * branch entries. If this flag is set, *buf* may be NULL. + * + * **-EINVAL** if arguments invalid or **size** not a multiple + * of sizeof(struct perf_branch_entry). + * + * **-ENOENT** if architecture does not support branch records. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3012,7 +3031,8 @@ union bpf_attr { FN(probe_read_kernel_str), \ FN(tcp_send_ack), \ FN(send_signal_thread), \ - FN(jiffies64), + FN(jiffies64), \ + FN(read_branch_records), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call @@ -3091,6 +3111,9 @@ enum bpf_func_id { /* BPF_FUNC_sk_storage_get flags */ #define BPF_SK_STORAGE_GET_F_CREATE (1ULL << 0) +/* BPF_FUNC_read_branch_records flags. */ +#define BPF_F_GET_BRANCH_RECORDS_SIZE (1ULL << 0) + /* Mode for BPF_FUNC_skb_adjust_room helper. */ enum bpf_adj_room_mode { BPF_ADJ_ROOM_NET, -- cgit