Commit 42fdbbde authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

selftests/bpf: A pro/epilogue test when the main prog jumps back to the 1st insn 



This patch adds a pro/epilogue test when the main prog has a goto insn
that goes back to the very first instruction of the prog. It is
to test the correctness of the adjust_jmp_off(prog, 0, delta)
after the verifier has applied the prologue and/or epilogue patch.

Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240829210833.388152-9-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b191b0fd

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

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <test_progs.h>

#include "pro_epilogue.skel.h"

#include "epilogue_tailcall.skel.h"

#include "pro_epilogue_goto_start.skel.h"



struct st_ops_args {

	__u64 a;
@@ -51,6 +52,7 @@ static void test_tailcall(void) 
void test_pro_epilogue(void)

{

	RUN_TESTS(pro_epilogue);

	RUN_TESTS(pro_epilogue_goto_start);

	if (test__start_subtest("tailcall"))

		test_tailcall();

}

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

0 → 100644
+149 −0
Original line number Diff line number Diff line 
// 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";



__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: if r1 == 0x0 goto pc+5")

__xlated("5: if r1 == 0x1 goto pc+2")

__xlated("6: r1 = 1")

__xlated("7: goto pc-3")

__xlated("8: r1 = 0")

__xlated("9: goto pc-6")

__xlated("10: r0 = 0")

__xlated("11: exit")

SEC("struct_ops/test_prologue_goto_start")

__naked int test_prologue_goto_start(void)

{

	asm volatile (

	"if r1 == 0 goto +5;"

	"if r1 == 1 goto +2;"

	"r1 = 1;"

	"goto -3;"

	"r1 = 0;"

	"goto -6;"

	"r0 = 0;"

	"exit;"

	::: __clobber_all);

}



__success

/* save __u64 *ctx to stack */

__xlated("0: *(u64 *)(r10 -8) = r1")

/* main prog */

__xlated("1: if r1 == 0x0 goto pc+5")

__xlated("2: if r1 == 0x1 goto pc+2")

__xlated("3: r1 = 1")

__xlated("4: goto pc-3")

__xlated("5: r1 = 0")

__xlated("6: goto pc-6")

__xlated("7: r0 = 0")

/* epilogue */

__xlated("8: r1 = *(u64 *)(r10 -8)")

__xlated("9: r1 = *(u64 *)(r1 +0)")

__xlated("10: r6 = *(u64 *)(r1 +0)")

__xlated("11: r6 += 10000")

__xlated("12: *(u64 *)(r1 +0) = r6")

__xlated("13: r0 = r6")

__xlated("14: r0 *= 2")

__xlated("15: exit")

SEC("struct_ops/test_epilogue_goto_start")

__naked int test_epilogue_goto_start(void)

{

	asm volatile (

	"if r1 == 0 goto +5;"

	"if r1 == 1 goto +2;"

	"r1 = 1;"

	"goto -3;"

	"r1 = 0;"

	"goto -6;"

	"r0 = 0;"

	"exit;"

	::: __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: if r1 == 0x0 goto pc+5")

__xlated("6: if r1 == 0x1 goto pc+2")

__xlated("7: r1 = 1")

__xlated("8: goto pc-3")

__xlated("9: r1 = 0")

__xlated("10: goto pc-6")

__xlated("11: r0 = 0")

/* epilogue */

__xlated("12: r1 = *(u64 *)(r10 -8)")

__xlated("13: r1 = *(u64 *)(r1 +0)")

__xlated("14: r6 = *(u64 *)(r1 +0)")

__xlated("15: r6 += 10000")

__xlated("16: *(u64 *)(r1 +0) = r6")

__xlated("17: r0 = r6")

__xlated("18: r0 *= 2")

__xlated("19: exit")

SEC("struct_ops/test_pro_epilogue_goto_start")

__naked int test_pro_epilogue_goto_start(void)

{

	asm volatile (

	"if r1 == 0 goto +5;"

	"if r1 == 1 goto +2;"

	"r1 = 1;"

	"goto -3;"

	"r1 = 0;"

	"goto -6;"

	"r0 = 0;"

	"exit;"

	::: __clobber_all);

}



SEC(".struct_ops.link")

struct bpf_testmod_st_ops epilogue_goto_start = {

	.test_prologue = (void *)test_prologue_goto_start,

	.test_epilogue = (void *)test_epilogue_goto_start,

	.test_pro_epilogue = (void *)test_pro_epilogue_goto_start,

};



SEC("syscall")

__retval(0)

int syscall_prologue_goto_start(void *ctx)

{

	struct st_ops_args args = {};



	return bpf_kfunc_st_ops_test_prologue(&args);

}



SEC("syscall")

__retval(20000) /* (EPILOGUE_A [10000]) * 2 */

int syscall_epilogue_goto_start(void *ctx)

{

	struct st_ops_args args = {};



	return bpf_kfunc_st_ops_test_epilogue(&args);

}



SEC("syscall")

__retval(22000) /* (PROLOGUE_A [1000] + EPILOGUE_A [10000]) * 2 */

int syscall_pro_epilogue_goto_start(void *ctx)

{

	struct st_ops_args args = {};



	return bpf_kfunc_st_ops_test_pro_epilogue(&args);

}