From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 69-171-232-181.mail-mxout.facebook.com (69-171-232-181.mail-mxout.facebook.com [69.171.232.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 614A9242D97 for ; Wed, 9 Sep 2026 06:26:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=69.171.232.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788935194; cv=none; b=sGlBf7ezo9Yla5TLK3ja0H17FG/cU11s1GZZIltfrnZ3DZWSnVazNyO8e0BZaAtHv0xs522h3B3x5dyid9NPjfGCGnfKzZ/f2aI+8a9H1LUOSyRBQ1K+cDsAfdD9qQfAJStxTh3pfLqSxHo1k3DU2KbPRAx0/2h+oRok/v6ptds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788935194; c=relaxed/simple; bh=/iMXBmPHVJKzeNz7QFVZjo3gxyfjeCtluc1cuXTF4XA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mD5jO38u4blfR5EDWPEk+XLQoX4md6ab/YbQMiNhbYMCTooo+Wq2dsYUfrj3bYkGR8cO0xILmThrMHIu32XsKsWcz+yaP7G9bs6LhtVNVYpWO54V7YMswRGbeW66LJ0CDKG1SNxndIuBwu6TOQPFmARxGc6Bl0RYRdD15PdMXEA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev; spf=fail smtp.mailfrom=linux.dev; arc=none smtp.client-ip=69.171.232.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devvm16039.vll0.facebook.com (Postfix, from userid 128203) id 46145299489757; Tue, 8 Sep 2026 23:26:26 -0700 (PDT) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , kernel-team@fb.com Subject: [PATCH bpf-next v2 12/12] selftests/bpf: Add tests for by-value kfunc arguments Date: Tue, 8 Sep 2026 23:26:26 -0700 Message-ID: <20260909062626.4009860-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260909062522.4001896-1-yonghong.song@linux.dev> References: <20260909062522.4001896-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Add kfuncs taking a 16-byte struct and an __int128 by value, with combinations of <=3D 8 byte arguments and '> 8 && <=3D 16' byte arguments= , and tests that call them. Each checks the value the kfunc returns, so a misplaced argument shows up rather than passing quietly. Between them the cases cover an argument the two conventions place alike, one arm64 moves between registers, one an ABI moves to or from the stack, and one both ABIs pad the stack for. All of them run on both arches; what differs is how many instructions the JIT emits to get there. Two more cover the rejections that hold everywhere, an aggregate holding a pointer and one too large to pass by value. test_stack_arg_big() in stack_arg_fail.c passed a 16-byte struct as the sixth argument and asserted the unrecognized stack argument type it used to be reported as. The JIT places that argument now, so the test is removed and the same call is covered by the cases above. Signed-off-by: Yonghong Song --- .../selftests/bpf/prog_tests/aggregate_arg.c | 2 + .../selftests/bpf/progs/aggregate_arg_kfunc.c | 221 ++++++++++++++++++ .../testing/selftests/bpf/progs/arena_kfunc.c | 16 ++ .../selftests/bpf/progs/stack_arg_fail.c | 10 - .../selftests/bpf/test_kmods/bpf_testmod.c | 77 ++++++ .../bpf/test_kmods/bpf_testmod_kfunc.h | 32 +++ 6 files changed, 348 insertions(+), 10 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/aggregate_arg_kfunc= .c diff --git a/tools/testing/selftests/bpf/prog_tests/aggregate_arg.c b/too= ls/testing/selftests/bpf/prog_tests/aggregate_arg.c index b230f3bd3b2a..aa7562f48737 100644 --- a/tools/testing/selftests/bpf/prog_tests/aggregate_arg.c +++ b/tools/testing/selftests/bpf/prog_tests/aggregate_arg.c @@ -2,8 +2,10 @@ /* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ #include #include "aggregate_arg_func.skel.h" +#include "aggregate_arg_kfunc.skel.h" =20 void test_aggregate_arg(void) { RUN_TESTS(aggregate_arg_func); + RUN_TESTS(aggregate_arg_kfunc); } diff --git a/tools/testing/selftests/bpf/progs/aggregate_arg_kfunc.c b/to= ols/testing/selftests/bpf/progs/aggregate_arg_kfunc.c new file mode 100644 index 000000000000..1d70bc8c03fd --- /dev/null +++ b/tools/testing/selftests/bpf/progs/aggregate_arg_kfunc.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */ +#include +#include +#include "../test_kmods/bpf_testmod_kfunc.h" +#include "bpf_misc.h" + +typedef unsigned __int128 u128; + +#define MIX_A 0xdeadbeefcafef00dULL +#define MIX_B 0x0123456789abcdefULL + +#if defined(__clang__) + +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_struct(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + struct prog_test_pair_arg s =3D { .lo =3D a, .hi =3D b }; + + if (bpf_kfunc_call_test_pair_arg(1, s, 2) !=3D a + b + 3) + return 1; + + return 0; +} + +#endif + +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_int128(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + u128 v =3D ((u128)a << 64) | b; + + if (bpf_kfunc_call_test_i128_arg(1, 2, v) !=3D a + b + 3) + return 1; + + return 0; +} + +/* + * arm64 rounds the register number up to an even one for an argument + * aligned to 16 bytes, so it wants this __int128 in x2 and x3. + * The x86-64 ABI has no such rule. + */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_int128_odd(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + u128 v =3D ((u128)a << 64) | b; + + if (bpf_kfunc_call_test_i128_arg_odd(1, v, 2) !=3D a + b + 3) + return 1; + + return 0; +} + +#if defined(__clang__) && defined(__BPF_FEATURE_STACK_ARGUMENT) + +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_last_regs(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + struct prog_test_pair_arg s =3D { .lo =3D a, .hi =3D b }; + + if (bpf_kfunc_call_test_pair_arg_nofit(1, 2, 3, 4, s) !=3D a + b + 10) + return 1; + + return 0; +} + +/* + * The x86-64 ABI moves an argument its six remaining registers cannot h= old + * wholly onto the stack. arm64 , with eight argument registers, still h= as a + * pair for it. + */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_straddle(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + struct prog_test_big_arg s =3D { .a =3D a, .b =3D b }; + + if (bpf_kfunc_call_stack_arg_big(1, 2, 3, 4, 5, s) !=3D a + b + 15) + return 1; + + return 0; +} + +/* The same, with an argument after the struct to take the eighth regist= er. */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_tail(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + struct prog_test_pair_arg s =3D { .lo =3D a, .hi =3D b }; + + if (bpf_kfunc_call_test_pair_arg_tail(1, 2, 3, 4, 5, s, 6) !=3D a + b += 21) + return 1; + + return 0; +} + +/* + * arm64 gives no register to an argument its eight registers cannot hol= d, + * nor to anything after it. Past its six registers the x86-64 ABI has b= oth + * eightbytes on the stack either way. + */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_split8(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + struct prog_test_pair_arg s =3D { .lo =3D a, .hi =3D b }; + + if (bpf_kfunc_call_test_pair_arg_split8(1, 2, 3, 4, 5, 6, 7, s) !=3D a = + b + 28) + return 1; + + return 0; +} + +/* + * The same hole, with enough arguments after the __int128 that the shif= t + * reaches the registers the BPF convention counts as stack slots: arm64 + * wants the last one in x6 where the BPF convention put it in x5. + */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_int128_shift(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + u128 v =3D ((u128)a << 64) | b; + + if (bpf_kfunc_call_test_i128_arg_shift(1, v, 2, 3, 4) !=3D a + b + 10) + return 1; + + return 0; +} + +/* + * One argument further and the hole pushes the last one off x7 and onto= the + * arm64 stack, which the JIT does not shift into. The x86-64 ABI packs = the + * eightbytes, so its last two are on the stack where BPF put them. + */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_int128_ovf(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + u128 v =3D ((u128)a << 64) | b; + + if (bpf_kfunc_call_test_i128_arg_ovf(1, v, 2, 3, 4, 5, 6) !=3D a + b + = 21) + return 1; + + return 0; +} + +/* + * Both conventions pad the stack to align this __int128, and the BPF + * convention pads for neither, so both JITs move it up an eightbyte. + */ +SEC("tc") +__arch_x86_64 __arch_arm64 +__load_if_JITed() +__success __retval(0) +int aggregate_arg_kfunc_int128_pad(struct __sk_buff *skb) +{ + __u64 a =3D skb->len ^ MIX_A; + __u64 b =3D skb->len ^ MIX_B; + u128 v =3D ((u128)a << 64) | b; + + if (bpf_kfunc_call_test_i128_arg_pad(1, 2, 3, 4, 5, 6, 7, v) !=3D a + b= + 28) + return 1; + + return 0; +} + +#endif + +SEC("tc") +__arch_x86_64 __arch_arm64 +__failure __msg("R1 type STRUCT is not composed of scalars") +int aggregate_arg_kfunc_ptr_member(struct __sk_buff *skb) +{ + struct prog_test_ptr_arg s =3D { .p =3D skb, .x =3D 1 }; + + return bpf_kfunc_call_test_ptr_arg(s); +} + +char _license[] SEC("license") =3D "GPL"; diff --git a/tools/testing/selftests/bpf/progs/arena_kfunc.c b/tools/test= ing/selftests/bpf/progs/arena_kfunc.c index 50609f3b0564..8d1ce360a309 100644 --- a/tools/testing/selftests/bpf/progs/arena_kfunc.c +++ b/tools/testing/selftests/bpf/progs/arena_kfunc.c @@ -228,6 +228,22 @@ int arena_arg_stack(void *ctx) bpf_kfunc_arena_stack_arg_test(1, 2, 3, 4, 5, (u64 *)1); return 0; } + +#if defined(__clang__) +/* The struct takes two slots, so the arena pointer is the sixth. */ +SEC("syscall") +__arch_x86_64 +__arch_arm64 +__failure __msg("arena pointer cannot be a stack argument") +int arena_arg_stack_after_pair(void *ctx) +{ + struct prog_test_pair_arg s =3D { .lo =3D 1, .hi =3D 2 }; + + bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0); + bpf_kfunc_call_test_pair_arena_arg(1, 2, 3, s, (u64 *)1); + return 0; +} +#endif #else SEC("syscall") __arch_x86_64 diff --git a/tools/testing/selftests/bpf/progs/stack_arg_fail.c b/tools/t= esting/selftests/bpf/progs/stack_arg_fail.c index eed97d582515..fff2e947ea33 100644 --- a/tools/testing/selftests/bpf/progs/stack_arg_fail.c +++ b/tools/testing/selftests/bpf/progs/stack_arg_fail.c @@ -3,20 +3,10 @@ =20 #include #include -#include "../test_kmods/bpf_testmod_kfunc.h" #include "bpf_misc.h" =20 #if defined(__BPF_FEATURE_STACK_ARGUMENT) =20 -SEC("tc") -__failure __msg("Unrecognized *(R11-8) type STRUCT") -int test_stack_arg_big(struct __sk_buff *skb) -{ - struct prog_test_big_arg s =3D { .a =3D 1, .b =3D 2 }; - - return bpf_kfunc_call_stack_arg_big(1, 2, 3, 4, 5, s); -} - SEC("socket") __description("r11 in ALU instruction") __failure __msg("R11 is invalid") diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools= /testing/selftests/bpf/test_kmods/bpf_testmod.c index f798bbbb4d13..baccee6fdad4 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -1029,6 +1029,72 @@ __bpf_kfunc struct prog_test_ret_pair bpf_kfunc_ca= ll_test_ret_fastcall(u64 a, u6 return r; } =20 +__bpf_kfunc u64 bpf_kfunc_call_test_pair_arg(u64 a, struct prog_test_pai= r_arg s, u64 b) +{ + return a + s.lo + s.hi + b; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_i128_arg(u64 a, u64 b, __int128 v) +{ + return a + b + (u64)((unsigned __int128)v >> 64) + (u64)v; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_i128_arg_odd(u64 a, __int128 v, u64 = b) +{ + return a + b + (u64)((unsigned __int128)v >> 64) + (u64)v; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_i128_arg_shift(u64 a, __int128 v, u6= 4 b, u64 c, + u64 d) +{ + return a + b + c + d + (u64)((unsigned __int128)v >> 64) + (u64)v; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_i128_arg_ovf(u64 a, __int128 v, u64 = b, u64 c, + u64 d, u64 e, u64 f) +{ + return a + b + c + d + e + f + + (u64)((unsigned __int128)v >> 64) + (u64)v; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_i128_arg_pad(u64 a, u64 b, u64 c, u6= 4 d, u64 e, + u64 f, u64 g, __int128 v) +{ + return a + b + c + d + e + f + g + + (u64)((unsigned __int128)v >> 64) + (u64)v; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_pair_arg_nofit(u64 a, u64 b, u64 c, = u64 d, + struct prog_test_pair_arg s) +{ + return a + b + c + d + s.lo + s.hi; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_pair_arg_tail(u64 a, u64 b, u64 c, u= 64 d, u64 e, + struct prog_test_pair_arg s, u64 f) +{ + return a + b + c + d + e + s.lo + s.hi + f; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_pair_arg_split8(u64 a, u64 b, u64 c,= u64 d, u64 e, + u64 f, u64 g, + struct prog_test_pair_arg s) +{ + return a + b + c + d + e + f + g + s.lo + s.hi; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_ptr_arg(struct prog_test_ptr_arg s) +{ + return s.x; +} + +__bpf_kfunc u64 bpf_kfunc_call_test_pair_arena_arg(u64 a, u64 b, u64 c, + struct prog_test_pair_arg s, + u64 *f__arena) +{ + return a + b + c + s.lo + s.hi + *f__arena; +} + __bpf_kfunc struct prog_test_ret_ptr bpf_kfunc_call_test_ret_ptr(u64 tag= ) { struct prog_test_ret_ptr r =3D { .p =3D NULL, .tag =3D tag }; @@ -1667,6 +1733,17 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_ret_arr_str= uct) BTF_ID_FLAGS(func, bpf_kfunc_call_test_ret_arr2d) BTF_ID_FLAGS(func, bpf_kfunc_call_test_ret_deep) BTF_ID_FLAGS(func, bpf_kfunc_call_test_ret_ii) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_pair_arg) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_i128_arg) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_i128_arg_odd) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_i128_arg_shift) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_i128_arg_ovf) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_i128_arg_pad) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_pair_arg_nofit) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_pair_arg_tail) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_pair_arg_split8) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_ptr_arg) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_pair_arena_arg) #endif BTF_ID_FLAGS(func, bpf_kfunc_call_test_ret_big) BTF_ID_FLAGS(func, bpf_kfunc_call_stack_arg) diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h b= /tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h index b213ef14848b..195ec37d5bbc 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h @@ -61,6 +61,16 @@ struct prog_test_big_arg { __u64 b; }; =20 +struct prog_test_pair_arg { /* 16 bytes: two argument registers */ + __u64 lo; + __u64 hi; +}; + +struct prog_test_ptr_arg { /* 16 bytes, but holds a pointer */ + void *p; + __u64 x; +}; + struct prog_test_ret_pair { /* 16 bytes: R0:R2 */ __u64 lo; __u64 hi; @@ -221,6 +231,28 @@ __int128 bpf_kfunc_call_test_i128(__u64 a, __u64 b) = __ksym; struct prog_test_ret_pair bpf_kfunc_call_test_ret_pair(__u64 a, __u64 b)= __ksym; struct prog_test_ret_pair bpf_kfunc_call_test_ret_fastcall(__u64 a, __u6= 4 b) __ksym; struct prog_test_ret_ii bpf_kfunc_call_test_ret_ii(int a, int b) __ksym; +__u64 bpf_kfunc_call_test_pair_arg(__u64 a, struct prog_test_pair_arg s,= __u64 b) __ksym; +#ifdef __SIZEOF_INT128__ +__u64 bpf_kfunc_call_test_i128_arg(__u64 a, __u64 b, __int128 v) __ksym; +__u64 bpf_kfunc_call_test_i128_arg_odd(__u64 a, __int128 v, __u64 b) __k= sym; +__u64 bpf_kfunc_call_test_i128_arg_shift(__u64 a, __int128 v, __u64 b, _= _u64 c, + __u64 d) __ksym; +__u64 bpf_kfunc_call_test_i128_arg_ovf(__u64 a, __int128 v, __u64 b, __u= 64 c, + __u64 d, __u64 e, __u64 f) __ksym; +__u64 bpf_kfunc_call_test_i128_arg_pad(__u64 a, __u64 b, __u64 c, __u64 = d, __u64 e, + __u64 f, __u64 g, __int128 v) __ksym; +#endif +__u64 bpf_kfunc_call_test_pair_arg_nofit(__u64 a, __u64 b, __u64 c, __u6= 4 d, + struct prog_test_pair_arg s) __ksym; +__u64 bpf_kfunc_call_test_pair_arg_tail(__u64 a, __u64 b, __u64 c, __u64= d, __u64 e, + struct prog_test_pair_arg s, __u64 f) __ksym; +__u64 bpf_kfunc_call_test_pair_arg_split8(__u64 a, __u64 b, __u64 c, __u= 64 d, __u64 e, + __u64 f, __u64 g, + struct prog_test_pair_arg s) __ksym; +__u64 bpf_kfunc_call_test_ptr_arg(struct prog_test_ptr_arg s) __ksym; +__u64 bpf_kfunc_call_test_pair_arena_arg(__u64 a, __u64 b, __u64 c, + struct prog_test_pair_arg s, + __u64 *f__arena) __ksym; struct prog_test_ret_ptr bpf_kfunc_call_test_ret_ptr(__u64 tag) __ksym; struct prog_test_ret_nested bpf_kfunc_call_test_ret_nested(__u64 tag) __= ksym; struct prog_test_ret_ptr_arr bpf_kfunc_call_test_ret_ptr_arr(void) __ksy= m; --=20 2.53.0-Meta