Commit 30c5bd96 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

selftests/bpf: Demonstrate use of custom .rodata/.data sections 



Enhance existing selftests to demonstrate the use of custom
.data/.rodata sections.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211021014404.2635234-9-andrii@kernel.org
parent aed65917

tools/testing/selftests/bpf/prog_tests/skeleton.c

+29 −0
Original line number Diff line number Diff line
@@ -16,10 +16,13 @@ void test_skeleton(void) 
	struct test_skeleton* skel;

	struct test_skeleton__bss *bss;

	struct test_skeleton__data *data;

	struct test_skeleton__data_dyn *data_dyn;

	struct test_skeleton__rodata *rodata;

	struct test_skeleton__rodata_dyn *rodata_dyn;

	struct test_skeleton__kconfig *kcfg;

	const void *elf_bytes;

	size_t elf_bytes_sz = 0;

	int i;



	skel = test_skeleton__open();

	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
@@ -30,7 +33,12 @@ void test_skeleton(void) 


	bss = skel->bss;

	data = skel->data;

	data_dyn = skel->data_dyn;

	rodata = skel->rodata;

	rodata_dyn = skel->rodata_dyn;



	ASSERT_STREQ(bpf_map__name(skel->maps.rodata_dyn), ".rodata.dyn", "rodata_dyn_name");

	ASSERT_STREQ(bpf_map__name(skel->maps.data_dyn), ".data.dyn", "data_dyn_name");



	/* validate values are pre-initialized correctly */

	CHECK(data->in1 != -1, "in1", "got %d != exp %d\n", data->in1, -1);
@@ -46,6 +54,12 @@ void test_skeleton(void) 
	CHECK(rodata->in.in6 != 0, "in6", "got %d != exp %d\n", rodata->in.in6, 0);

	CHECK(bss->out6 != 0, "out6", "got %d != exp %d\n", bss->out6, 0);



	ASSERT_EQ(rodata_dyn->in_dynarr_sz, 0, "in_dynarr_sz");

	for (i = 0; i < 4; i++)

		ASSERT_EQ(rodata_dyn->in_dynarr[i], -(i + 1), "in_dynarr");

	for (i = 0; i < 4; i++)

		ASSERT_EQ(data_dyn->out_dynarr[i], i + 1, "out_dynarr");



	/* validate we can pre-setup global variables, even in .bss */

	data->in1 = 10;

	data->in2 = 11;
@@ -53,6 +67,10 @@ void test_skeleton(void) 
	bss->in4 = 13;

	rodata->in.in6 = 14;



	rodata_dyn->in_dynarr_sz = 4;

	for (i = 0; i < 4; i++)

		rodata_dyn->in_dynarr[i] = i + 10;



	err = test_skeleton__load(skel);

	if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))

		goto cleanup;
@@ -64,6 +82,10 @@ void test_skeleton(void) 
	CHECK(bss->in4 != 13, "in4", "got %lld != exp %lld\n", bss->in4, 13LL);

	CHECK(rodata->in.in6 != 14, "in6", "got %d != exp %d\n", rodata->in.in6, 14);



	ASSERT_EQ(rodata_dyn->in_dynarr_sz, 4, "in_dynarr_sz");

	for (i = 0; i < 4; i++)

		ASSERT_EQ(rodata_dyn->in_dynarr[i], i + 10, "in_dynarr");



	/* now set new values and attach to get them into outX variables */

	data->in1 = 1;

	data->in2 = 2;
@@ -73,6 +95,8 @@ void test_skeleton(void) 
	bss->in5.b = 6;

	kcfg = skel->kconfig;



	skel->data_read_mostly->read_mostly_var = 123;



	err = test_skeleton__attach(skel);

	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))

		goto cleanup;
@@ -93,6 +117,11 @@ void test_skeleton(void) 
	CHECK(bss->kern_ver != kcfg->LINUX_KERNEL_VERSION, "ext2",

	      "got %d != exp %d\n", bss->kern_ver, kcfg->LINUX_KERNEL_VERSION);



	for (i = 0; i < 4; i++)

		ASSERT_EQ(data_dyn->out_dynarr[i], i + 10, "out_dynarr");



	ASSERT_EQ(skel->bss->out_mostly_var, 123, "out_mostly_var");



	elf_bytes = test_skeleton__elf_bytes(&elf_bytes_sz);

	ASSERT_OK_PTR(elf_bytes, "elf_bytes");

	ASSERT_GE(elf_bytes_sz, 0, "elf_bytes_sz");

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

+18 −0
Original line number Diff line number Diff line
@@ -5,6 +5,8 @@ 
#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>



#define __read_mostly SEC(".data.read_mostly")



struct s {

	int a;

	long long b;
@@ -40,9 +42,20 @@ int kern_ver = 0; 


struct s out5 = {};





const volatile int in_dynarr_sz SEC(".rodata.dyn");

const volatile int in_dynarr[4] SEC(".rodata.dyn") = { -1, -2, -3, -4 };



int out_dynarr[4] SEC(".data.dyn") = { 1, 2, 3, 4 };



int read_mostly_var __read_mostly;

int out_mostly_var;



SEC("raw_tp/sys_enter")

int handler(const void *ctx)

{

	int i;



	out1 = in1;

	out2 = in2;

	out3 = in3;
@@ -53,6 +66,11 @@ int handler(const void *ctx) 
	bpf_syscall = CONFIG_BPF_SYSCALL;

	kern_ver = LINUX_KERNEL_VERSION;



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

		out_dynarr[i] = in_dynarr[i];



	out_mostly_var = read_mostly_var;



	return 0;

}