From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
This test adds a new struct_ops "bpf_testmod_st_ops" in bpf_testmod.
The ops of the bpf_testmod_st_ops is triggered by new kfunc calls
"bpf_kfunc_st_ops_test_*logue". These new kfunc calls are
primarily used by the SEC("syscall") program. The test triggering
sequence is like:
SEC("syscall")
syscall_prologue(struct st_ops_args *args)
bpf_kfunc_st_op_test_prologue(args)
st_ops->test_prologue(args)
.gen_prologue adds 1000 to args->a
.gen_epilogue adds 10000 to args->a
.gen_epilogue will also set the r0 to 2 * args->a.
The .gen_prologue and .gen_epilogue of the bpf_testmod_st_ops
will test the prog->aux->attach_func_name to decide if
it needs to generate codes.
The main programs of the pro_epilogue.c will call a
new kfunc bpf_kfunc_st_ops_inc10 which does "args->a += 10".
It will also call a subprog() which does "args->a += 1".
This patch uses the test_loader infra to check the __xlated
instructions patched after gen_prologue and/or gen_epilogue.
The __xlated check is based on Eduard's example (Thanks!) in v1.
args->a is returned by the struct_ops prog (either the main prog
or the epilogue). Thus, the __retval of the SEC("syscall") prog
is checked. For example, when triggering the ops in the
'SEC("struct_ops/test_epilogue") int test_epilogue'
The expected args->a is +1 (subprog call) + 10 (kfunc call)
+ 10000 (.gen_epilogue) = 10011.
The expected return value is 2 * 10011 (.gen_epilogue).
Suggested-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
---
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 190 ++++++++++++++++++
.../selftests/bpf/bpf_testmod/bpf_testmod.h | 11 +
.../bpf/bpf_testmod/bpf_testmod_kfunc.h | 6 +
.../selftests/bpf/prog_tests/pro_epilogue.c | 10 +
.../selftests/bpf/progs/pro_epilogue.c | 154 ++++++++++++++
5 files changed, 371 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/pro_epilogue.c
create mode 100644 tools/testing/selftests/bpf/progs/pro_epilogue.c
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 8a71a91b752d..42c38dbb6835 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -17,6 +17,7 @@
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/un.h>
+#include <linux/filter.h>
#include <net/sock.h>
#include <linux/namei.h>
#include "bpf_testmod.h"
@@ -945,6 +946,51 @@ __bpf_kfunc int bpf_kfunc_call_kernel_getpeername(struct addr_args *args)
return err;
}
+static DEFINE_MUTEX(st_ops_mutex);
+static struct bpf_testmod_st_ops *st_ops;
+
+__bpf_kfunc int bpf_kfunc_st_ops_test_prologue(struct st_ops_args *args)
+{
+ int ret = -1;
+
+ mutex_lock(&st_ops_mutex);
+ if (st_ops && st_ops->test_prologue)
+ ret = st_ops->test_prologue(args);
+ mutex_unlock(&st_ops_mutex);
+
+ return ret;
+}
+
+__bpf_kfunc int bpf_kfunc_st_ops_test_epilogue(struct st_ops_args *args)
+{
+ int ret = -1;
+
+ mutex_lock(&st_ops_mutex);
+ if (st_ops && st_ops->test_epilogue)
+ ret = st_ops->test_epilogue(args);
+ mutex_unlock(&st_ops_mutex);
+
+ return ret;
+}
+
+__bpf_kfunc int bpf_kfunc_st_ops_test_pro_epilogue(struct st_ops_args *args)
+{
+ int ret = -1;
+
+ mutex_lock(&st_ops_mutex);
+ if (st_ops && st_ops->test_pro_epilogue)
+ ret = st_ops->test_pro_epilogue(args);
+ mutex_unlock(&st_ops_mutex);
+
+ return ret;
+}
+
+__bpf_kfunc int bpf_kfunc_st_ops_inc10(struct st_ops_args *args)
+{
+ args->a += 10;
+ return args->a;
+}
+
BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -981,6 +1027,10 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_sendmsg, KF_SLEEPABLE)
BTF_ID_FLAGS(func, bpf_kfunc_call_sock_sendmsg, KF_SLEEPABLE)
BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getsockname, KF_SLEEPABLE)
BTF_ID_FLAGS(func, bpf_kfunc_call_kernel_getpeername, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_prologue, KF_TRUSTED_ARGS | KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_epilogue, KF_TRUSTED_ARGS | KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_pro_epilogue, KF_TRUSTED_ARGS | KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_kfunc_st_ops_inc10, KF_TRUSTED_ARGS)
BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
static int bpf_testmod_ops_init(struct btf *btf)
@@ -1100,6 +1150,144 @@ struct bpf_struct_ops bpf_testmod_ops2 = {
.owner = THIS_MODULE,
};
+static int bpf_test_mod_st_ops__test_prologue(struct st_ops_args *args)
+{
+ return 0;
+}
+
+static int bpf_test_mod_st_ops__test_epilogue(struct st_ops_args *args)
+{
+ return 0;
+}
+
+static int bpf_test_mod_st_ops__test_pro_epilogue(struct st_ops_args *args)
+{
+ return 0;
+}
+
+static int st_ops_gen_prologue(struct bpf_insn *insn_buf, bool direct_write,
+ const struct bpf_prog *prog)
+{
+ struct bpf_insn *insn = insn_buf;
+
+ if (strcmp(prog->aux->attach_func_name, "test_prologue") &&
+ strcmp(prog->aux->attach_func_name, "test_pro_epilogue"))
+ return 0;
+
+ /* r6 = r1[0]; // r6 will be "struct st_ops *args". r1 is "u64 *ctx".
+ * r7 = r6->a;
+ * r7 += 1000;
+ * r6->a = r7;
+ */
+ *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0);
+ *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_6, offsetof(struct st_ops_args, a));
+ *insn++ = BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, 1000);
+ *insn++ = BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, offsetof(struct st_ops_args, a));
+ *insn++ = prog->insnsi[0];
+
+ return insn - insn_buf;
+}
+
+static int st_ops_gen_epilogue(struct bpf_insn *insn_buf, const struct bpf_prog *prog,
+ s16 ctx_stack_off)
+{
+ struct bpf_insn *insn = insn_buf;
+
+ if (strcmp(prog->aux->attach_func_name, "test_epilogue") &&
+ strcmp(prog->aux->attach_func_name, "test_pro_epilogue"))
+ return 0;
+
+ /* r1 = stack[ctx_stack_off]; // r1 will be "u64 *ctx"
+ * r1 = r1[0]; // r1 will be "struct st_ops *args"
+ * r6 = r1->a;
+ * r6 += 10000;
+ * r1->a = r6;
+ * r0 = r6;
+ * r0 *= 2;
+ * BPF_EXIT;
+ */
+ *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_FP, ctx_stack_off);
+ *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 0);
+ *insn++ = BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct st_ops_args, a));
+ *insn++ = BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 10000);
+ *insn++ = BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, offsetof(struct st_ops_args, a));
+ *insn++ = BPF_MOV64_REG(BPF_REG_0, BPF_REG_6);
+ *insn++ = BPF_ALU64_IMM(BPF_MUL, BPF_REG_0, 2);
+ *insn++ = BPF_EXIT_INSN();
+
+ return insn - insn_buf;
+}
+
+static int st_ops_btf_struct_access(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, int size)
+{
+ if (off < 0 || off + size > sizeof(struct st_ops_args))
+ return -EACCES;
+ return 0;
+}
+
+static const struct bpf_verifier_ops st_ops_verifier_ops = {
+ .is_valid_access = bpf_testmod_ops_is_valid_access,
+ .btf_struct_access = st_ops_btf_struct_access,
+ .gen_prologue = st_ops_gen_prologue,
+ .gen_epilogue = st_ops_gen_epilogue,
+ .get_func_proto = bpf_base_func_proto,
+};
+
+static struct bpf_testmod_st_ops st_ops_cfi_stubs = {
+ .test_prologue = bpf_test_mod_st_ops__test_prologue,
+ .test_epilogue = bpf_test_mod_st_ops__test_epilogue,
+ .test_pro_epilogue = bpf_test_mod_st_ops__test_pro_epilogue,
+};
+
+static int st_ops_reg(void *kdata, struct bpf_link *link)
+{
+ int err = 0;
+
+ mutex_lock(&st_ops_mutex);
+ if (st_ops) {
+ pr_err("st_ops has already been registered\n");
+ err = -EEXIST;
+ goto unlock;
+ }
+ st_ops = kdata;
+
+unlock:
+ mutex_unlock(&st_ops_mutex);
+ return err;
+}
+
+static void st_ops_unreg(void *kdata, struct bpf_link *link)
+{
+ mutex_lock(&st_ops_mutex);
+ st_ops = NULL;
+ mutex_unlock(&st_ops_mutex);
+}
+
+static int st_ops_init(struct btf *btf)
+{
+ return 0;
+}
+
+static int st_ops_init_member(const struct btf_type *t,
+ const struct btf_member *member,
+ void *kdata, const void *udata)
+{
+ return 0;
+}
+
+static struct bpf_struct_ops testmod_st_ops = {
+ .verifier_ops = &st_ops_verifier_ops,
+ .init = st_ops_init,
+ .init_member = st_ops_init_member,
+ .reg = st_ops_reg,
+ .unreg = st_ops_unreg,
+ .cfi_stubs = &st_ops_cfi_stubs,
+ .name = "bpf_testmod_st_ops",
+ .owner = THIS_MODULE,
+};
+
extern int bpf_fentry_test1(int a);
static int bpf_testmod_init(void)
@@ -1117,8 +1305,10 @@ static int bpf_testmod_init(void)
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_testmod_kfunc_set);
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set);
+ ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_testmod_kfunc_set);
ret = ret ?: register_bpf_struct_ops(&bpf_bpf_testmod_ops, bpf_testmod_ops);
ret = ret ?: register_bpf_struct_ops(&bpf_testmod_ops2, bpf_testmod_ops2);
+ ret = ret ?: register_bpf_struct_ops(&testmod_st_ops, bpf_testmod_st_ops);
ret = ret ?: register_btf_id_dtor_kfuncs(bpf_testmod_dtors,
ARRAY_SIZE(bpf_testmod_dtors),
THIS_MODULE);
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
index fe0d402b0d65..fb7dff47597a 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
@@ -94,4 +94,15 @@ struct bpf_testmod_ops2 {
int (*test_1)(void);
};
+struct st_ops_args {
+ u64 a;
+};
+
+struct bpf_testmod_st_ops {
+ int (*test_prologue)(struct st_ops_args *args);
+ int (*test_epilogue)(struct st_ops_args *args);
+ int (*test_pro_epilogue)(struct st_ops_args *args);
+ struct module *owner;
+};
+
#endif /* _BPF_TESTMOD_H */
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
index c6c314965bb1..7e76532be5fa 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
@@ -148,4 +148,10 @@ struct sk_buff *bpf_kfunc_nested_acquire_nonzero_offset_test(struct sk_buff_head
struct sk_buff *bpf_kfunc_nested_acquire_zero_offset_test(struct sock_common *ptr) __ksym;
void bpf_kfunc_nested_release_test(struct sk_buff *ptr) __ksym;
+struct st_ops_args;
+int bpf_kfunc_st_ops_test_prologue(struct st_ops_args *args) __ksym;
+int bpf_kfunc_st_ops_test_epilogue(struct st_ops_args *args) __ksym;
+int bpf_kfunc_st_ops_test_pro_epilogue(struct st_ops_args *args) __ksym;
+int bpf_kfunc_st_ops_inc10(struct st_ops_args *args) __ksym;
+
#endif /* _BPF_TESTMOD_KFUNC_H */
diff --git a/tools/testing/selftests/bpf/prog_tests/pro_epilogue.c b/tools/testing/selftests/bpf/prog_tests/pro_epilogue.c
new file mode 100644
index 000000000000..00b806804b99
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/pro_epilogue.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include <test_progs.h>
+#include "pro_epilogue.skel.h"
+
+void test_pro_epilogue(void)
+{
+ RUN_TESTS(pro_epilogue);
+}
diff --git a/tools/testing/selftests/bpf/progs/pro_epilogue.c b/tools/testing/selftests/bpf/progs/pro_epilogue.c
new file mode 100644
index 000000000000..44bc3f06b4b6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/pro_epilogue.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+#include "../bpf_testmod/bpf_testmod.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
+
+char _license[] SEC("license") = "GPL";
+
+void __kfunc_btf_root(void)
+{
+ bpf_kfunc_st_ops_inc10(NULL);
+}
+
+static __noinline __used int subprog(struct st_ops_args *args)
+{
+ args->a += 1;
+ return args->a;
+}
+
+__success
+/* prologue */
+__xlated("0: r6 = *(u64 *)(r1 +0)")
+__xlated("1: r7 = *(u64 *)(r6 +0)")
+__xlated("2: r7 += 1000")
+__xlated("3: *(u64 *)(r6 +0) = r7")
+/* main prog */
+__xlated("4: r1 = *(u64 *)(r1 +0)")
+__xlated("5: r6 = r1")
+__xlated("6: call kernel-function")
+__xlated("7: r1 = r6")
+__xlated("8: call pc+1")
+__xlated("9: exit")
+SEC("struct_ops/test_prologue")
+__naked int test_prologue(void)
+{
+ asm volatile (
+ "r1 = *(u64 *)(r1 +0);"
+ "r6 = r1;"
+ "call %[bpf_kfunc_st_ops_inc10];"
+ "r1 = r6;"
+ "call subprog;"
+ "exit;"
+ :
+ : __imm(bpf_kfunc_st_ops_inc10)
+ : __clobber_all);
+}
+
+__success
+/* save __u64 *ctx to stack */
+__xlated("0: *(u64 *)(r10 -8) = r1")
+/* main prog */
+__xlated("1: r1 = *(u64 *)(r1 +0)")
+__xlated("2: r6 = r1")
+__xlated("3: call kernel-function")
+__xlated("4: r1 = r6")
+__xlated("5: call pc+")
+/* epilogue */
+__xlated("6: r1 = *(u64 *)(r10 -8)")
+__xlated("7: r1 = *(u64 *)(r1 +0)")
+__xlated("8: r6 = *(u64 *)(r1 +0)")
+__xlated("9: r6 += 10000")
+__xlated("10: *(u64 *)(r1 +0) = r6")
+__xlated("11: r0 = r6")
+__xlated("12: r0 *= 2")
+__xlated("13: exit")
+SEC("struct_ops/test_epilogue")
+__naked int test_epilogue(void)
+{
+ asm volatile (
+ "r1 = *(u64 *)(r1 +0);"
+ "r6 = r1;"
+ "call %[bpf_kfunc_st_ops_inc10];"
+ "r1 = r6;"
+ "call subprog;"
+ "exit;"
+ :
+ : __imm(bpf_kfunc_st_ops_inc10)
+ : __clobber_all);
+}
+
+__success
+/* prologue */
+__xlated("0: r6 = *(u64 *)(r1 +0)")
+__xlated("1: r7 = *(u64 *)(r6 +0)")
+__xlated("2: r7 += 1000")
+__xlated("3: *(u64 *)(r6 +0) = r7")
+/* save __u64 *ctx to stack */
+__xlated("4: *(u64 *)(r10 -8) = r1")
+/* main prog */
+__xlated("5: r1 = *(u64 *)(r1 +0)")
+__xlated("6: r6 = r1")
+__xlated("7: call kernel-function")
+__xlated("8: r1 = r6")
+__xlated("9: call pc+")
+/* epilogue */
+__xlated("10: r1 = *(u64 *)(r10 -8)")
+__xlated("11: r1 = *(u64 *)(r1 +0)")
+__xlated("12: r6 = *(u64 *)(r1 +0)")
+__xlated("13: r6 += 10000")
+__xlated("14: *(u64 *)(r1 +0) = r6")
+__xlated("15: r0 = r6")
+__xlated("16: r0 *= 2")
+__xlated("17: exit")
+SEC("struct_ops/test_pro_epilogue")
+__naked int test_pro_epilogue(void)
+{
+ asm volatile (
+ "r1 = *(u64 *)(r1 +0);"
+ "r6 = r1;"
+ "call %[bpf_kfunc_st_ops_inc10];"
+ "r1 = r6;"
+ "call subprog;"
+ "exit;"
+ :
+ : __imm(bpf_kfunc_st_ops_inc10)
+ : __clobber_all);
+}
+
+SEC("syscall")
+__retval(1011) /* PROLOGUE_A [1000] + KFUNC_INC10 + SUBPROG_A [1] */
+int syscall_prologue(void *ctx)
+{
+ struct st_ops_args args = {};
+
+ return bpf_kfunc_st_ops_test_prologue(&args);
+}
+
+SEC("syscall")
+__retval(20022) /* (KFUNC_INC10 + SUBPROG_A [1] + EPILOGUE_A [10000]) * 2 */
+int syscall_epilogue(void *ctx)
+{
+ struct st_ops_args args = {};
+
+ return bpf_kfunc_st_ops_test_epilogue(&args);
+}
+
+SEC("syscall")
+__retval(22022) /* (PROLOGUE_A [1000] + KFUNC_INC10 + SUBPROG_A [1] + EPILOGUE_A [10000]) * 2 */
+int syscall_pro_epilogue(void *ctx)
+{
+ struct st_ops_args args = {};
+
+ return bpf_kfunc_st_ops_test_pro_epilogue(&args);
+}
+
+SEC(".struct_ops.link")
+struct bpf_testmod_st_ops pro_epilogue = {
+ .test_prologue = (void *)test_prologue,
+ .test_epilogue = (void *)test_epilogue,
+ .test_pro_epilogue = (void *)test_pro_epilogue,
+};
--
2.43.5
