From patchwork Fri Jun 13 07:37:10 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alexis_Lothor=C3=A9_=28eBPF_Foundation=29?= X-Patchwork-Id: 897216 Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 524202F2C48; Fri, 13 Jun 2025 07:37:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.196 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749800262; cv=none; b=tYw9Bgvb1ohUnXE+934SlG4FpMITrmqlW/QkTR1TN/InxLdtRNeuOiYDygTPE6XDqEJa1Uifq9RlXuk1SMQw1v6fOdVtcn8paiTdMtmQQzWs2naQ/bnYYz4Fpi2EsYx5dd0sLXmbrp/YZogqaFumo6jE6/HEsGbasdd6O2BtsUA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749800262; c=relaxed/simple; bh=r99sJfu4ewPRyz0zJbWXJMYkpw47S2rIyZaupP+jn1g=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Asnr47XufE5fM8TKd2uS9Q22SnFePE6xGBSbevUIqLe4fp0vfNcbj68wTFcECBqwsgG7OOgzYYpy1yk8THmF000Mq1b6jGeuyrnIqEfUu3pcKIFV1ExjtSiqOQFaWGCm9fshQScR1/dF5bAPKh4uSOleAK/74+XlUI8Nx2lN5Ic= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=cAFx4niw; arc=none smtp.client-ip=217.70.183.196 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="cAFx4niw" Received: by mail.gandi.net (Postfix) with ESMTPSA id CCC6B44506; Fri, 13 Jun 2025 07:37:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1749800250; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rWrXudQ87v1aByOGhl67T4UU7KUM5mT6FEm5oZqhcLg=; b=cAFx4niwDDsyQFKGdmMcGf11CvIpcE6i60PNTLVL6XAEHr8QsvAnUtPgghd0BMq2R+ppDC FFai5U507SCN+pyoN6wuDoWlTMOjSSoP4TnpNxYiC+w0QbX1ZUzPQlhl134JonesXJvjFx OWDw6aSbLFZe7FDXXsBj2S+b7DQHMXAKYwDHAWLiIwLUr5ryMSKFEAsH//6LX4WvBNf7+B RTSk1TpiSwF389Xnh71A9SzYutIAanBG+/eJ2O3NS8i6MD2qG3qY8IPYR+kJcbwUdA/tQF SzpnBSDBVvIxVqUtGLlQS7VmjGVpj6a1tNP17AMJbhSHMVv02WVX06WVxtBTDQ== From: =?utf-8?q?Alexis_Lothor=C3=A9_=28eBPF_Foundation=29?= Date: Fri, 13 Jun 2025 09:37:10 +0200 Subject: [PATCH bpf 1/7] bpf/x86: use define for max regs count used for arguments Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250613-deny_trampoline_structs_on_stack-v1-1-5be9211768c3@bootlin.com> References: <20250613-deny_trampoline_structs_on_stack-v1-0-5be9211768c3@bootlin.com> In-Reply-To: <20250613-deny_trampoline_structs_on_stack-v1-0-5be9211768c3@bootlin.com> To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , "David S. Miller" , David Ahern , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Menglong Dong , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Pu Lehui , Puranjay Mohan , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Ilya Leoshkevich , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Hari Bathini , Christophe Leroy , Naveen N Rao , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Mykola Lysenko , Shuah Khan , Maxime Coquelin , Alexandre Torgue Cc: ebpf@linuxfoundation.org, Thomas Petazzoni , Bastien Curutchet , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?b?QmrDtnJuIFQ=?= =?utf-8?b?w7ZwZWw=?= , linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kselftest@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, =?utf-8?q?Alexis_Lothor=C3=A9_=28eBP?= =?utf-8?q?F_Foundation=29?= X-Mailer: b4 0.14.2 X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddugddujeefjecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephfffufggtgfgkfhfjgfvvefosehtkeertdertdejnecuhfhrohhmpeetlhgvgihishcunfhothhhohhrroculdgvuefrhfcuhfhouhhnuggrthhiohhnmdcuoegrlhgvgihishdrlhhothhhohhrvgessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepleejkeetffefveelgeeklefhtefhgfeigeduveffjeehleeifeefjedtudejgeeunecukfhppedvrgdtvdemkeegvdekmehfleegtgemvgdttdemmehfkeehnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddvmeekgedvkeemfhelgegtmegvtddtmeemfhekhedphhgvlhhopegludelvddrudeikedruddrudeljegnpdhmrghilhhfrhhomheprghlvgigihhsrdhlohhthhhorhgvsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopeehkedprhgtphhtthhopehsohhngheskhgvrhhnvghlrdhorhhgpdhrtghpthhtoheprghgohhruggvvghvsehlihhnuhigrdhisghmrdgtohhmpdhrtghpthhtoheplhhinhhugihpphgtqdguvghvsehlihhsthhsrdhoiihlrggsshdrohhrghdprhgtphhtthhopehlihhnuhigq dhkshgvlhhfthgvshhtsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqshhtmhefvdesshhtqdhmugdqmhgrihhlmhgrnhdrshhtohhrmhhrvghplhihrdgtohhmpdhrtghpthhtoheprghlvgigrghnughrvgdrthhorhhguhgvsehfohhsshdrshhtrdgtohhmpdhrtghpthhtohepmhihkhholhgrlhesfhgsrdgtohhmpdhrtghpthhtohepshhvvghnsheslhhinhhugidrihgsmhdrtghomh X-GND-Sasl: alexis.lothore@bootlin.com x86 allows using up to 6 registers to pass arguments between function calls. This value is hardcoded in multiple places, use a define for this value. Signed-off-by: Alexis Lothoré (eBPF Foundation) --- arch/x86/net/bpf_jit_comp.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 15672cb926fc1817f97d2cd1c55d1575803f6958..9689834de1bb1a90fdc28156e0e2a56ac0ff2076 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -61,6 +61,8 @@ static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len) #define EMIT_ENDBR_POISON() #endif +#define MAX_REGS_FOR_ARGS 6 + static bool is_imm8(int value) { return value <= 127 && value >= -128; @@ -2710,10 +2712,10 @@ static int get_nr_used_regs(const struct btf_func_model *m) for (i = 0; i < min_t(int, m->nr_args, MAX_BPF_FUNC_ARGS); i++) { arg_regs = (m->arg_size[i] + 7) / 8; - if (nr_used_regs + arg_regs <= 6) + if (nr_used_regs + arg_regs <= MAX_REGS_FOR_ARGS) nr_used_regs += arg_regs; - if (nr_used_regs >= 6) + if (nr_used_regs >= MAX_REGS_FOR_ARGS) break; } @@ -2751,7 +2753,7 @@ static void save_args(const struct btf_func_model *m, u8 **prog, * the arg1-5,arg7 will be passed by regs, and arg6 will * by stack. */ - if (nr_regs + arg_regs > 6) { + if (nr_regs + arg_regs > MAX_REGS_FOR_ARGS) { /* copy function arguments from origin stack frame * into current stack frame. * @@ -2811,7 +2813,7 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, */ for (i = 0; i < min_t(int, m->nr_args, MAX_BPF_FUNC_ARGS); i++) { arg_regs = (m->arg_size[i] + 7) / 8; - if (nr_regs + arg_regs <= 6) { + if (nr_regs + arg_regs <= MAX_REGS_FOR_ARGS) { for (j = 0; j < arg_regs; j++) { emit_ldx(prog, BPF_DW, nr_regs == 5 ? X86_REG_R9 : BPF_REG_1 + nr_regs, @@ -2824,7 +2826,7 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, stack_size -= 8 * arg_regs; } - if (nr_regs >= 6) + if (nr_regs >= MAX_REGS_FOR_ARGS) break; } } @@ -3149,7 +3151,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im stack_size += (sizeof(struct bpf_tramp_run_ctx) + 7) & ~0x7; run_ctx_off = stack_size; - if (nr_regs > 6 && (flags & BPF_TRAMP_F_CALL_ORIG)) { + if (nr_regs > MAX_REGS_FOR_ARGS && (flags & BPF_TRAMP_F_CALL_ORIG)) { /* the space that used to pass arguments on-stack */ stack_size += (nr_regs - get_nr_used_regs(m)) * 8; /* make sure the stack pointer is 16-byte aligned if we