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

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

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20211021014404.2635234-9-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2021-10-20 18:44:02 -07:00 committed by Alexei Starovoitov
parent aed659170a
commit 30c5bd9647
2 changed files with 47 additions and 0 deletions
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29
tools/testing/selftests/bpf/prog_tests/skeleton.c
View File

@ -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");

18
tools/testing/selftests/bpf/progs/test_skeleton.c
View File

@ -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;
}