Commit 4d9c5c53 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

test_bpf: add bpf_skb_vlan_push/pop() tests 



improve accuracy of timing in test_bpf and add two stress tests:
- {skb->data[0], get_smp_processor_id} repeated 2k times
- {skb->data[0], vlan_push} x 68 followed by {skb->data[0], vlan_pop} x 68

1st test is useful to test performance of JIT implementation of BPF_LD_ABS
together with BPF_CALL instructions.
2nd test is stressing skb_vlan_push/pop logic together with skb->data access
via BPF_LD_ABS insn which checks that re-caching of skb->data is done correctly.

In order to call bpf_skb_vlan_push() from test_bpf.ko have to add
three export_symbol_gpl.

Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4e10df9a

kernel/bpf/core.c

+1 −0
Original line number Diff line number Diff line
@@ -177,6 +177,7 @@ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 
{

	return 0;

}

EXPORT_SYMBOL_GPL(__bpf_call_base);



/**

 *	__bpf_prog_run - run eBPF program on a given context

lib/test_bpf.c

+95 −3
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/init.h>

#include <linux/module.h>

#include <linux/filter.h>

#include <linux/bpf.h>

#include <linux/skbuff.h>

#include <linux/netdevice.h>

#include <linux/if_vlan.h>
@@ -355,6 +356,81 @@ static int bpf_fill_ja(struct bpf_test *self) 
	return __bpf_fill_ja(self, 12, 9);

}



static int bpf_fill_ld_abs_get_processor_id(struct bpf_test *self)

{

	unsigned int len = BPF_MAXINSNS;

	struct sock_filter *insn;

	int i;



	insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);

	if (!insn)

		return -ENOMEM;



	for (i = 0; i < len - 1; i += 2) {

		insn[i] = __BPF_STMT(BPF_LD | BPF_B | BPF_ABS, 0);

		insn[i + 1] = __BPF_STMT(BPF_LD | BPF_W | BPF_ABS,

					 SKF_AD_OFF + SKF_AD_CPU);

	}



	insn[len - 1] = __BPF_STMT(BPF_RET | BPF_K, 0xbee);



	self->u.ptr.insns = insn;

	self->u.ptr.len = len;



	return 0;

}



#define PUSH_CNT 68

/* test: {skb->data[0], vlan_push} x 68 + {skb->data[0], vlan_pop} x 68 */

static int bpf_fill_ld_abs_vlan_push_pop(struct bpf_test *self)

{

	unsigned int len = BPF_MAXINSNS;

	struct bpf_insn *insn;

	int i = 0, j, k = 0;



	insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);

	if (!insn)

		return -ENOMEM;



	insn[i++] = BPF_MOV64_REG(R6, R1);

loop:

	for (j = 0; j < PUSH_CNT; j++) {

		insn[i++] = BPF_LD_ABS(BPF_B, 0);

		insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0x34, len - i - 2);

		i++;

		insn[i++] = BPF_MOV64_REG(R1, R6);

		insn[i++] = BPF_MOV64_IMM(R2, 1);

		insn[i++] = BPF_MOV64_IMM(R3, 2);

		insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,

					 bpf_skb_vlan_push_proto.func - __bpf_call_base);

		insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0, len - i - 2);

		i++;

	}



	for (j = 0; j < PUSH_CNT; j++) {

		insn[i++] = BPF_LD_ABS(BPF_B, 0);

		insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0x34, len - i - 2);

		i++;

		insn[i++] = BPF_MOV64_REG(R1, R6);

		insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,

					 bpf_skb_vlan_pop_proto.func - __bpf_call_base);

		insn[i] = BPF_JMP_IMM(BPF_JNE, R0, 0, len - i - 2);

		i++;

	}

	if (++k < 5)

		goto loop;



	for (; i < len - 1; i++)

		insn[i] = BPF_ALU32_IMM(BPF_MOV, R0, 0xbef);



	insn[len - 1] = BPF_EXIT_INSN();



	self->u.ptr.insns = insn;

	self->u.ptr.len = len;



	return 0;

}



static struct bpf_test tests[] = {

	{

		"TAX",
@@ -4398,6 +4474,22 @@ static struct bpf_test tests[] = { 
		{ { 0, 0xababcbac } },

		.fill_helper = bpf_fill_maxinsns11,

	},

	{

		"BPF_MAXINSNS: ld_abs+get_processor_id",

		{ },

		CLASSIC,

		{ },

		{ { 1, 0xbee } },

		.fill_helper = bpf_fill_ld_abs_get_processor_id,

	},

	{

		"BPF_MAXINSNS: ld_abs+vlan_push/pop",

		{ },

		INTERNAL,

		{ 0x34 },

		{ { 1, 0xbef } },

		.fill_helper = bpf_fill_ld_abs_vlan_push_pop,

	},

};



static struct net_device dev;
@@ -4551,14 +4643,14 @@ static int __run_one(const struct bpf_prog *fp, const void *data, 
	u64 start, finish;

	int ret = 0, i;



	start = ktime_to_us(ktime_get());

	start = ktime_get_ns();



	for (i = 0; i < runs; i++)

		ret = BPF_PROG_RUN(fp, data);



	finish = ktime_to_us(ktime_get());

	finish = ktime_get_ns();



	*duration = (finish - start) * 1000ULL;

	*duration = finish - start;

	do_div(*duration, runs);



	return ret;

net/core/filter.c

+2 −0
Original line number Diff line number Diff line
@@ -1457,6 +1457,7 @@ const struct bpf_func_proto bpf_skb_vlan_push_proto = { 
	.arg2_type      = ARG_ANYTHING,

	.arg3_type      = ARG_ANYTHING,

};

EXPORT_SYMBOL_GPL(bpf_skb_vlan_push_proto);



static u64 bpf_skb_vlan_pop(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)

{
@@ -1471,6 +1472,7 @@ const struct bpf_func_proto bpf_skb_vlan_pop_proto = { 
	.ret_type       = RET_INTEGER,

	.arg1_type      = ARG_PTR_TO_CTX,

};

EXPORT_SYMBOL_GPL(bpf_skb_vlan_pop_proto);



bool bpf_helper_changes_skb_data(void *func)

{

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