Re: [RFC v1 09/14] krsi: Add a helper function for bpf_perf_event_output
From: Yonghong Song <hidden>
Date: 2019-09-14 18:24:27
Also in:
bpf, lkml
On 9/10/19 12:55 PM, KP Singh wrote:
From: KP Singh <redacted>
This helper is mapped to the existing operation
BPF_FUNC_perf_event_output.
An example usage of this function would be:
#define BUF_SIZE 64;
struct bpf_map_def SEC("maps") perf_map = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = MAX_CPUS,
};
could you use a map definition similar to
tools/testing/selftests/bpf/progs/test_perf_buffer.c?
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(u32));
} perf_map SEC(".maps");
SEC("krsi")
int bpf_prog1(void *ctx)
{
char buf[BUF_SIZE];
int len;
u64 flags = BPF_F_CURRENT_CPU;
/* some logic that fills up buf with len data*/
len = fill_up_buf(buf);
if (len < 0)
return len;
if (len > BU)BUF_SIZE?
return 0; bpf_perf_event_output(ctx, &perf_map, flags, buf len);
buf, len?
quoted hunk ↗ jump to hunk
return 0; } A sample program that showcases the use of bpf_perf_event_output is added later. Signed-off-by: KP Singh <redacted> --- security/krsi/ops.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)diff --git a/security/krsi/ops.c b/security/krsi/ops.c index a61508b7018f..57bd304a03f4 100644 --- a/security/krsi/ops.c +++ b/security/krsi/ops.c@@ -111,6 +111,26 @@ static bool krsi_prog_is_valid_access(int off, int size, return false; } +BPF_CALL_5(krsi_event_output, void *, log,
Maybe name the first argument as 'ctx' to follow typical helper convention?
quoted hunk ↗ jump to hunk
+ struct bpf_map *, map, u64, flags, void *, data, u64, size) +{ + if (unlikely(flags & ~(BPF_F_INDEX_MASK))) + return -EINVAL; + + return bpf_event_output(map, flags, data, size, NULL, 0, NULL); +} + +static const struct bpf_func_proto krsi_event_output_proto = { + .func = krsi_event_output, + .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_MEM, + .arg5_type = ARG_CONST_SIZE_OR_ZERO, +}; + static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog@@ -121,6 +141,8 @@ static const struct bpf_func_proto *krsi_prog_func_proto(enum bpf_func_id return &bpf_map_lookup_elem_proto; case BPF_FUNC_get_current_pid_tgid: return &bpf_get_current_pid_tgid_proto; + case BPF_FUNC_perf_event_output: + return &krsi_event_output_proto; default: return NULL; }