From: Yonghong Song <yonghong.song@linux.dev>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"Jose E . Marchesi" <jose.marchesi@oracle.com>,
kernel-team@fb.com, Martin KaFai Lau <martin.lau@kernel.org>,
Puranjay Mohan <puranjay@kernel.org>
Subject: [PATCH bpf-next v4 12/25] bpf: Prepare architecture JIT support for stack arguments
Date: Tue, 12 May 2026 21:50:54 -0700 [thread overview]
Message-ID: <20260513045054.2390945-1-yonghong.song@linux.dev> (raw)
In-Reply-To: <20260513044949.2382019-1-yonghong.song@linux.dev>
Add bpf_jit_supports_stack_args() as a weak function defaulting to
false. Architectures that implement JIT support for stack arguments
override it to return true.
Reject BPF functions with more than 5 parameters at verification
time if the architecture does not support stack arguments.
Acked-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
include/linux/filter.h | 1 +
kernel/bpf/btf.c | 8 +++++++-
kernel/bpf/core.c | 5 +++++
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 918d9b34eac6..a515a9769078 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1184,6 +1184,7 @@ bool bpf_jit_inlines_helper_call(s32 imm);
bool bpf_jit_supports_subprog_tailcalls(void);
bool bpf_jit_supports_percpu_insn(void);
bool bpf_jit_supports_kfunc_call(void);
+bool bpf_jit_supports_stack_args(void);
bool bpf_jit_supports_far_kfunc_call(void);
bool bpf_jit_supports_exceptions(void);
bool bpf_jit_supports_ptr_xchg(void);
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index ec3fb8c8f4ee..3d8080eba544 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -7886,8 +7886,14 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
MAX_BPF_FUNC_ARGS, tname, nargs);
return -EFAULT;
}
- if (nargs > MAX_BPF_FUNC_REG_ARGS)
+ if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+ if (!bpf_jit_supports_stack_args()) {
+ bpf_log(log, "JIT does not support function %s() with %d args\n",
+ tname, nargs);
+ return -EFAULT;
+ }
sub->stack_arg_cnt = nargs - MAX_BPF_FUNC_REG_ARGS;
+ }
if (is_global && nargs > MAX_BPF_FUNC_REG_ARGS) {
bpf_log(log, "global function %s has %d > %d args, stack args not supported\n",
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 958d86f0beac..e6b836f846eb 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -3217,6 +3217,11 @@ bool __weak bpf_jit_supports_kfunc_call(void)
return false;
}
+bool __weak bpf_jit_supports_stack_args(void)
+{
+ return false;
+}
+
bool __weak bpf_jit_supports_far_kfunc_call(void)
{
return false;
--
2.53.0-Meta
next prev parent reply other threads:[~2026-05-13 4:50 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-13 4:49 [PATCH bpf-next v4 00/25] bpf: Support stack arguments for BPF functions and kfuncs Yonghong Song
2026-05-13 4:49 ` [PATCH bpf-next v4 01/25] bpf: Convert bpf_get_spilled_reg macro to static inline function Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 02/25] bpf: Remove copy_register_state wrapper function Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 03/25] bpf: Add helper functions for r11-based stack argument insns Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 04/25] bpf: Set sub->arg_cnt earlier in btf_prepare_func_args() Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 05/25] bpf: Support stack arguments for bpf functions Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 06/25] bpf: Refactor jmp history to use dedicated spi/frame fields Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 07/25] bpf: Add precision marking and backtracking for stack argument slots Yonghong Song
2026-05-13 5:44 ` bot+bpf-ci
2026-05-13 4:50 ` [PATCH bpf-next v4 08/25] bpf: Refactor record_call_access() to extract per-arg logic Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 09/25] bpf: Use arg_is_fp() in has_fp_args() Yonghong Song
2026-05-13 4:50 ` [PATCH bpf-next v4 10/25] bpf: Extend liveness analysis to track stack argument slots Yonghong Song
2026-05-13 5:44 ` bot+bpf-ci
2026-05-13 4:50 ` [PATCH bpf-next v4 11/25] bpf: Reject stack arguments in non-JITed programs Yonghong Song
2026-05-13 5:33 ` bot+bpf-ci
2026-05-13 4:50 ` Yonghong Song [this message]
2026-05-13 5:33 ` [PATCH bpf-next v4 12/25] bpf: Prepare architecture JIT support for stack arguments bot+bpf-ci
2026-05-13 4:50 ` [PATCH bpf-next v4 13/25] bpf: Enable r11 based insns Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 14/25] bpf: Support stack arguments for kfunc calls Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 15/25] bpf: Reject stack arguments if tail call reachable Yonghong Song
2026-05-13 5:33 ` bot+bpf-ci
2026-05-13 4:51 ` [PATCH bpf-next v4 16/25] bpf: Disable private stack for x86_64 if stack arguments used Yonghong Song
2026-05-13 5:33 ` bot+bpf-ci
2026-05-13 4:51 ` [PATCH bpf-next v4 17/25] bpf,x86: Implement JIT support for stack arguments Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 18/25] selftests/bpf: Add tests for BPF function " Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 19/25] selftests/bpf: Add tests for stack argument validation Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 20/25] selftests/bpf: Add BTF fixup for __naked subprog parameter names Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 21/25] selftests/bpf: Add verifier tests for stack argument validation Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 22/25] selftests/bpf: Add precision backtracking test for stack arguments Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 23/25] bpf, arm64: Map BPF_REG_0 to x8 instead of x7 Yonghong Song
2026-05-13 4:51 ` [PATCH bpf-next v4 24/25] bpf, arm64: Add JIT support for stack arguments Yonghong Song
2026-05-13 4:52 ` [PATCH bpf-next v4 25/25] selftests/bpf: Enable stack argument tests for arm64 Yonghong Song
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260513045054.2390945-1-yonghong.song@linux.dev \
--to=yonghong.song@linux.dev \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=jose.marchesi@oracle.com \
--cc=kernel-team@fb.com \
--cc=martin.lau@kernel.org \
--cc=puranjay@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox