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4e4136c644
Test gen_prologue and gen_epilogue that generate kfuncs that have not
been seen in the main program.
The main bpf program and return value checks are identical to
pro_epilogue.c introduced in commit 47e69431b5 ("selftests/bpf: Test
gen_prologue and gen_epilogue"). However, now when bpf_testmod_st_ops
detects a program name with prefix "test_kfunc_", it generates slightly
different prologue and epilogue: They still add 1000 to args->a in
prologue, add 10000 to args->a and set r0 to 2 * args->a in epilogue,
but involve kfuncs.
At high level, the alternative version of prologue and epilogue look
like this:
cgrp = bpf_cgroup_from_id(0);
if (cgrp)
bpf_cgroup_release(cgrp);
else
/* Perform what original bpf_testmod_st_ops prologue or
* epilogue does
*/
Since 0 is never a valid cgroup id, the original prologue or epilogue
logic will be performed. As a result, the __retval check should expect
the exact same return value.
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250225233545.285481-2-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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#include "../test_kmods/bpf_testmod.h"
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#include "../test_kmods/bpf_testmod_kfunc.h"
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char _license[] SEC("license") = "GPL";
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void __kfunc_btf_root(void)
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{
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bpf_kfunc_st_ops_inc10(NULL);
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}
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static __noinline __used int subprog(struct st_ops_args *args)
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{
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args->a += 1;
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return args->a;
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}
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__success
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/* prologue */
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__xlated("0: r8 = r1")
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__xlated("1: r1 = 0")
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__xlated("2: call kernel-function")
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__xlated("3: if r0 != 0x0 goto pc+5")
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__xlated("4: r6 = *(u64 *)(r8 +0)")
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__xlated("5: r7 = *(u64 *)(r6 +0)")
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__xlated("6: r7 += 1000")
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__xlated("7: *(u64 *)(r6 +0) = r7")
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__xlated("8: goto pc+2")
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__xlated("9: r1 = r0")
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__xlated("10: call kernel-function")
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__xlated("11: r1 = r8")
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/* save __u64 *ctx to stack */
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__xlated("12: *(u64 *)(r10 -8) = r1")
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/* main prog */
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__xlated("13: r1 = *(u64 *)(r1 +0)")
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__xlated("14: r6 = r1")
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__xlated("15: call kernel-function")
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__xlated("16: r1 = r6")
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__xlated("17: call pc+")
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/* epilogue */
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__xlated("18: r1 = 0")
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__xlated("19: r6 = 0")
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__xlated("20: call kernel-function")
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__xlated("21: if r0 != 0x0 goto pc+6")
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__xlated("22: r1 = *(u64 *)(r10 -8)")
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__xlated("23: r1 = *(u64 *)(r1 +0)")
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__xlated("24: r6 = *(u64 *)(r1 +0)")
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__xlated("25: r6 += 10000")
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__xlated("26: *(u64 *)(r1 +0) = r6")
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__xlated("27: goto pc+2")
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__xlated("28: r1 = r0")
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__xlated("29: call kernel-function")
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__xlated("30: r0 = r6")
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__xlated("31: r0 *= 2")
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__xlated("32: exit")
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SEC("struct_ops/test_pro_epilogue")
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__naked int test_kfunc_pro_epilogue(void)
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{
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asm volatile (
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"r1 = *(u64 *)(r1 +0);"
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"r6 = r1;"
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"call %[bpf_kfunc_st_ops_inc10];"
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"r1 = r6;"
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"call subprog;"
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"exit;"
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:
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: __imm(bpf_kfunc_st_ops_inc10)
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: __clobber_all);
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}
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SEC("syscall")
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__retval(22022) /* (PROLOGUE_A [1000] + KFUNC_INC10 + SUBPROG_A [1] + EPILOGUE_A [10000]) * 2 */
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int syscall_pro_epilogue(void *ctx)
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{
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struct st_ops_args args = {};
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return bpf_kfunc_st_ops_test_pro_epilogue(&args);
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}
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SEC(".struct_ops.link")
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struct bpf_testmod_st_ops pro_epilogue_with_kfunc = {
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.test_pro_epilogue = (void *)test_kfunc_pro_epilogue,
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};
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