Commit f9a7cf6e authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

bpf: Introduce BPF_TRACE_x helper for the tracing tests 



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: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191123202504.1502696-1-kafai@fb.com
parent b8cd76ca

tools/lib/bpf/bpf_helpers.h

+0 −13
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/bpf/bpf_trace_helpers.h

0 → 100644
+58 −0
Original line number Diff line number Diff line 
/* 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

tools/testing/selftests/bpf/progs/fentry_test.c

+18 −54
Original line number Diff line number Diff line
@@ -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;

}

tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c

+9 −18
Original line number Diff line number Diff line
@@ -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")

tools/testing/selftests/bpf/progs/fexit_test.c

+21 −62
Original line number Diff line number Diff line
@@ -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;

}

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