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bpf: Introduce BPF_TRACE_x helper for the tracing tests

Browse source 
For BPF_PROG_TYPE_TRACING, the bpf_prog's ctx is an array of u64.
This patch borrows the idea from BPF_CALL_x in filter.h to
convert a u64 to the arg type of the traced function.

The new BPF_TRACE_x has an arg to specify the return type of a bpf_prog.
It will be used in the future TCP-ops bpf_prog that may return "void".

The new macros are defined in the new header file "bpf_trace_helpers.h".
It is under selftests/bpf/ for now.  It could be moved to libbpf later
after seeing more upcoming non-tracing use cases.

The tests are changed to use these new macros also.  Hence,
the k[s]u8/16/32/64 are no longer needed and they are removed
from the bpf_helpers.h.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191123202504.1502696-1-kafai@fb.com
This commit is contained in:
Martin KaFai Lau 2019-11-23 12:25:04 -08:00 committed by Alexei Starovoitov
parent b8cd76ca4a
commit f9a7cf6eb1
7 changed files with 125 additions and 187 deletions
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13
tools/lib/bpf/bpf_helpers.h
View file

@ -44,17 +44,4 @@ enum libbpf_pin_type {
LIBBPF_PIN_BY_NAME,
};
/* The following types should be used by BPF_PROG_TYPE_TRACING program to
* access kernel function arguments. BPF trampoline and raw tracepoints
* typecast arguments to 'unsigned long long'.
*/
typedef int __attribute__((aligned(8))) ks32;
typedef char __attribute__((aligned(8))) ks8;
typedef short __attribute__((aligned(8))) ks16;
typedef long long __attribute__((aligned(8))) ks64;
typedef unsigned int __attribute__((aligned(8))) ku32;
typedef unsigned char __attribute__((aligned(8))) ku8;
typedef unsigned short __attribute__((aligned(8))) ku16;
typedef unsigned long long __attribute__((aligned(8))) ku64;
#endif

58
tools/testing/selftests/bpf/bpf_trace_helpers.h Normal file
View file

@ -0,0 +1,58 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __BPF_TRACE_HELPERS_H
#define __BPF_TRACE_HELPERS_H
#include "bpf_helpers.h"
#define __BPF_MAP_0(i, m, v, ...) v
#define __BPF_MAP_1(i, m, v, t, a, ...) m(t, a, ctx[i])
#define __BPF_MAP_2(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_1(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_3(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_2(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_4(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_3(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_5(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_4(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_6(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_5(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_7(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_6(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_8(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_7(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_9(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_8(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_10(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_9(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_11(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_10(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP_12(i, m, v, t, a, ...) m(t, a, ctx[i]), __BPF_MAP_11(i+1, m, v, __VA_ARGS__)
#define __BPF_MAP(n, ...) __BPF_MAP_##n(0, __VA_ARGS__)
/* BPF sizeof(void *) is always 8, so no need to cast to long first
* for ptr to avoid compiler warning.
*/
#define __BPF_CAST(t, a, ctx) (t) ctx
#define __BPF_V void
#define __BPF_N
#define __BPF_DECL_ARGS(t, a, ctx) t a
#define BPF_TRACE_x(x, sec_name, fname, ret_type, ...) \
static __always_inline ret_type \
____##fname(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \
\
SEC(sec_name) \
ret_type fname(__u64 *ctx) \
{ \
return ____##fname(__BPF_MAP(x, __BPF_CAST, __BPF_N, __VA_ARGS__));\
} \
\
static __always_inline \
ret_type ____##fname(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))
#define BPF_TRACE_0(sec, fname, ...) BPF_TRACE_x(0, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_1(sec, fname, ...) BPF_TRACE_x(1, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_2(sec, fname, ...) BPF_TRACE_x(2, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_3(sec, fname, ...) BPF_TRACE_x(3, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_4(sec, fname, ...) BPF_TRACE_x(4, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_5(sec, fname, ...) BPF_TRACE_x(5, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_6(sec, fname, ...) BPF_TRACE_x(6, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_7(sec, fname, ...) BPF_TRACE_x(7, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_8(sec, fname, ...) BPF_TRACE_x(8, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_9(sec, fname, ...) BPF_TRACE_x(9, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_10(sec, fname, ...) BPF_TRACE_x(10, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_11(sec, fname, ...) BPF_TRACE_x(11, sec, fname, int, __VA_ARGS__)
#define BPF_TRACE_12(sec, fname, ...) BPF_TRACE_x(12, sec, fname, int, __VA_ARGS__)
#endif

72
tools/testing/selftests/bpf/progs/fentry_test.c
View file

@ -2,89 +2,53 @@
/* Copyright (c) 2019 Facebook */
#include <linux/bpf.h>
#include "bpf_helpers.h"
#include "bpf_trace_helpers.h"
char _license[] SEC("license") = "GPL";
struct test1 {
ks32 a;
};
static volatile __u64 test1_result;
SEC("fentry/bpf_fentry_test1")
int test1(struct test1 *ctx)
BPF_TRACE_1("fentry/bpf_fentry_test1", test1, int, a)
{
test1_result = ctx->a == 1;
test1_result = a == 1;
return 0;
}
struct test2 {
ks32 a;
ku64 b;
};
static volatile __u64 test2_result;
SEC("fentry/bpf_fentry_test2")
int test2(struct test2 *ctx)
BPF_TRACE_2("fentry/bpf_fentry_test2", test2, int, a, __u64, b)
{
test2_result = ctx->a == 2 && ctx->b == 3;
test2_result = a == 2 && b == 3;
return 0;
}
struct test3 {
ks8 a;
ks32 b;
ku64 c;
};
static volatile __u64 test3_result;
SEC("fentry/bpf_fentry_test3")
int test3(struct test3 *ctx)
BPF_TRACE_3("fentry/bpf_fentry_test3", test3, char, a, int, b, __u64, c)
{
test3_result = ctx->a == 4 && ctx->b == 5 && ctx->c == 6;
test3_result = a == 4 && b == 5 && c == 6;
return 0;
}
struct test4 {
void *a;
ks8 b;
ks32 c;
ku64 d;
};
static volatile __u64 test4_result;
SEC("fentry/bpf_fentry_test4")
int test4(struct test4 *ctx)
BPF_TRACE_4("fentry/bpf_fentry_test4", test4,
void *, a, char, b, int, c, __u64, d)
{
test4_result = ctx->a == (void *)7 && ctx->b == 8 && ctx->c == 9 &&
ctx->d == 10;
test4_result = a == (void *)7 && b == 8 && c == 9 && d == 10;
return 0;
}
struct test5 {
ku64 a;
void *b;
ks16 c;
ks32 d;
ku64 e;
};
static volatile __u64 test5_result;
SEC("fentry/bpf_fentry_test5")
int test5(struct test5 *ctx)
BPF_TRACE_5("fentry/bpf_fentry_test5", test5,
__u64, a, void *, b, short, c, int, d, __u64, e)
{
test5_result = ctx->a == 11 && ctx->b == (void *)12 && ctx->c == 13 &&
ctx->d == 14 && ctx->e == 15;
test5_result = a == 11 && b == (void *)12 && c == 13 && d == 14 &&
e == 15;
return 0;
}
struct test6 {
ku64 a;
void *b;
ks16 c;
ks32 d;
void *e;
ks64 f;
};
static volatile __u64 test6_result;
SEC("fentry/bpf_fentry_test6")
int test6(struct test6 *ctx)
BPF_TRACE_6("fentry/bpf_fentry_test6", test6,
__u64, a, void *, b, short, c, int, d, void *, e, __u64, f)
{
test6_result = ctx->a == 16 && ctx->b == (void *)17 && ctx->c == 18 &&
ctx->d == 19 && ctx->e == (void *)20 && ctx->f == 21;
test6_result = a == 16 && b == (void *)17 && c == 18 && d == 19 &&
e == (void *)20 && f == 21;
return 0;
}

27
tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c
View file

@ -2,46 +2,37 @@
/* Copyright (c) 2019 Facebook */
#include <linux/bpf.h>
#include "bpf_helpers.h"
#include "bpf_trace_helpers.h"
struct sk_buff {
unsigned int len;
};
struct args {
struct sk_buff *skb;
ks32 ret;
};
static volatile __u64 test_result;
SEC("fexit/test_pkt_access")
int test_main(struct args *ctx)
BPF_TRACE_2("fexit/test_pkt_access", test_main,
struct sk_buff *, skb, int, ret)
{
struct sk_buff *skb = ctx->skb;
int len;
__builtin_preserve_access_index(({
len = skb->len;
}));
if (len != 74 || ctx->ret != 0)
if (len != 74 || ret != 0)
return 0;
test_result = 1;
return 0;
}
struct args_subprog1 {
struct sk_buff *skb;
ks32 ret;
};
static volatile __u64 test_result_subprog1;
SEC("fexit/test_pkt_access_subprog1")
int test_subprog1(struct args_subprog1 *ctx)
BPF_TRACE_2("fexit/test_pkt_access_subprog1", test_subprog1,
struct sk_buff *, skb, int, ret)
{
struct sk_buff *skb = ctx->skb;
int len;
__builtin_preserve_access_index(({
len = skb->len;
}));
if (len != 74 || ctx->ret != 148)
if (len != 74 || ret != 148)
return 0;
test_result_subprog1 = 1;
return 0;
@ -62,8 +53,8 @@ int test_subprog1(struct args_subprog1 *ctx)
* instead of accurate types.
*/
struct args_subprog2 {
ku64 args[5];
ku64 ret;
__u64 args[5];
__u64 ret;
};
static volatile __u64 test_result_subprog2;
SEC("fexit/test_pkt_access_subprog2")

83
tools/testing/selftests/bpf/progs/fexit_test.c
View file

@ -2,97 +2,56 @@
/* Copyright (c) 2019 Facebook */
#include <linux/bpf.h>
#include "bpf_helpers.h"
#include "bpf_trace_helpers.h"
char _license[] SEC("license") = "GPL";
struct test1 {
ks32 a;
ks32 ret;
};
static volatile __u64 test1_result;
SEC("fexit/bpf_fentry_test1")
int test1(struct test1 *ctx)
BPF_TRACE_2("fexit/bpf_fentry_test1", test1, int, a, int, ret)
{
test1_result = ctx->a == 1 && ctx->ret == 2;
test1_result = a == 1 && ret == 2;
return 0;
}
struct test2 {
ks32 a;
ku64 b;
ks32 ret;
};
static volatile __u64 test2_result;
SEC("fexit/bpf_fentry_test2")
int test2(struct test2 *ctx)
BPF_TRACE_3("fexit/bpf_fentry_test2", test2, int, a, __u64, b, int, ret)
{
test2_result = ctx->a == 2 && ctx->b == 3 && ctx->ret == 5;
test2_result = a == 2 && b == 3 && ret == 5;
return 0;
}
struct test3 {
ks8 a;
ks32 b;
ku64 c;
ks32 ret;
};
static volatile __u64 test3_result;
SEC("fexit/bpf_fentry_test3")
int test3(struct test3 *ctx)
BPF_TRACE_4("fexit/bpf_fentry_test3", test3, char, a, int, b, __u64, c, int, ret)
{
test3_result = ctx->a == 4 && ctx->b == 5 && ctx->c == 6 &&
ctx->ret == 15;
test3_result = a == 4 && b == 5 && c == 6 && ret == 15;
return 0;
}
struct test4 {
void *a;
ks8 b;
ks32 c;
ku64 d;
ks32 ret;
};
static volatile __u64 test4_result;
SEC("fexit/bpf_fentry_test4")
int test4(struct test4 *ctx)
BPF_TRACE_5("fexit/bpf_fentry_test4", test4,
void *, a, char, b, int, c, __u64, d, int, ret)
{
test4_result = ctx->a == (void *)7 && ctx->b == 8 && ctx->c == 9 &&
ctx->d == 10 && ctx->ret == 34;
test4_result = a == (void *)7 && b == 8 && c == 9 && d == 10 &&
ret == 34;
return 0;
}
struct test5 {
ku64 a;
void *b;
ks16 c;
ks32 d;
ku64 e;
ks32 ret;
};
static volatile __u64 test5_result;
SEC("fexit/bpf_fentry_test5")
int test5(struct test5 *ctx)
BPF_TRACE_6("fexit/bpf_fentry_test5", test5,
__u64, a, void *, b, short, c, int, d, __u64, e, int, ret)
{
test5_result = ctx->a == 11 && ctx->b == (void *)12 && ctx->c == 13 &&
ctx->d == 14 && ctx->e == 15 && ctx->ret == 65;
test5_result = a == 11 && b == (void *)12 && c == 13 && d == 14 &&
e == 15 && ret == 65;
return 0;
}
struct test6 {
ku64 a;
void *b;
ks16 c;
ks32 d;
void *e;
ks64 f;
ks32 ret;
};
static volatile __u64 test6_result;
SEC("fexit/bpf_fentry_test6")
int test6(struct test6 *ctx)
BPF_TRACE_7("fexit/bpf_fentry_test6", test6,
__u64, a, void *, b, short, c, int, d, void *, e, __u64, f,
int, ret)
{
test6_result = ctx->a == 16 && ctx->b == (void *)17 && ctx->c == 18 &&
ctx->d == 19 && ctx->e == (void *)20 && ctx->f == 21 &&
ctx->ret == 111;
test6_result = a == 16 && b == (void *)17 && c == 18 && d == 19 &&
e == (void *)20 && f == 21 && ret == 111;
return 0;
}

43
tools/testing/selftests/bpf/progs/kfree_skb.c
View file

@ -4,6 +4,7 @@
#include <stdbool.h>
#include "bpf_helpers.h"
#include "bpf_endian.h"
#include "bpf_trace_helpers.h"
char _license[] SEC("license") = "GPL";
struct {
@ -47,28 +48,18 @@ struct sk_buff {
char cb[48];
};
/* copy arguments from
* include/trace/events/skb.h:
* TRACE_EVENT(kfree_skb,
* TP_PROTO(struct sk_buff *skb, void *location),
*
* into struct below:
*/
struct trace_kfree_skb {
struct sk_buff *skb;
void *location;
};
struct meta {
int ifindex;
__u32 cb32_0;
__u8 cb8_0;
};
SEC("tp_btf/kfree_skb")
int trace_kfree_skb(struct trace_kfree_skb *ctx)
/* TRACE_EVENT(kfree_skb,
* TP_PROTO(struct sk_buff *skb, void *location),
*/
BPF_TRACE_2("tp_btf/kfree_skb", trace_kfree_skb,
struct sk_buff *, skb, void *, location)
{
struct sk_buff *skb = ctx->skb;
struct net_device *dev;
struct callback_head *ptr;
void *func;
@ -123,17 +114,10 @@ static volatile struct {
bool fexit_test_ok;
} result;
struct eth_type_trans_args {
struct sk_buff *skb;
struct net_device *dev;
unsigned short protocol; /* return value available to fexit progs */
};
SEC("fentry/eth_type_trans")
int fentry_eth_type_trans(struct eth_type_trans_args *ctx)
BPF_TRACE_3("fentry/eth_type_trans", fentry_eth_type_trans,
struct sk_buff *, skb, struct net_device *, dev,
unsigned short, protocol)
{
struct sk_buff *skb = ctx->skb;
struct net_device *dev = ctx->dev;
int len, ifindex;
__builtin_preserve_access_index(({
@ -148,11 +132,10 @@ int fentry_eth_type_trans(struct eth_type_trans_args *ctx)
return 0;
}
SEC("fexit/eth_type_trans")
int fexit_eth_type_trans(struct eth_type_trans_args *ctx)
BPF_TRACE_3("fexit/eth_type_trans", fexit_eth_type_trans,
struct sk_buff *, skb, struct net_device *, dev,
unsigned short, protocol)
{
struct sk_buff *skb = ctx->skb;
struct net_device *dev = ctx->dev;
int len, ifindex;
__builtin_preserve_access_index(({
@ -163,7 +146,7 @@ int fexit_eth_type_trans(struct eth_type_trans_args *ctx)
/* fexit sees packet without L2 header that eth_type_trans should have
* consumed.
*/
if (len != 60 || ctx->protocol != bpf_htons(0x86dd) || ifindex != 1)
if (len != 60 || protocol != bpf_htons(0x86dd) || ifindex != 1)
return 0;
result.fexit_test_ok = true;
return 0;

16
tools/testing/selftests/bpf/progs/test_overhead.c
View file

@ -3,6 +3,7 @@
#include <linux/bpf.h>
#include "bpf_helpers.h"
#include "bpf_tracing.h"
#include "bpf_trace_helpers.h"
SEC("kprobe/__set_task_comm")
int prog1(struct pt_regs *ctx)
@ -22,20 +23,15 @@ int prog3(struct bpf_raw_tracepoint_args *ctx)
return 0;
}
struct __set_task_comm_args {
struct task_struct *tsk;
const char *buf;
ku8 exec;
};
SEC("fentry/__set_task_comm")
int prog4(struct __set_task_comm_args *ctx)
struct task_struct;
BPF_TRACE_3("fentry/__set_task_comm", prog4,
struct task_struct *, tsk, const char *, buf, __u8, exec)
{
return 0;
}
SEC("fexit/__set_task_comm")
int prog5(struct __set_task_comm_args *ctx)
BPF_TRACE_3("fexit/__set_task_comm", prog5,
struct task_struct *, tsk, const char *, buf, __u8, exec)
{
return 0;
}