From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89788C28CBC for ; Wed, 6 May 2020 19:53:15 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 592B02075E for ; Wed, 6 May 2020 19:53:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="KyCGLZ9s"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="UNVpkMKk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 592B02075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+DtTRirrmvgPrd5xVkVe+KDb5bir0CFhXj0ZfcQVwmY=; b=KyCGLZ9sqWF4rt kHQojLbCQmdZt+DLkeLoq3fTO7QrzkLaoXz42hRb2hkIbNaPM8Qn5ySlCXdUaZC3h0DHRJFlcSd1R EXbyAU2M+cvPl6l9HiGvIbGRWzTcM6yPOO8Ns8MmVzPKmsJXIdxlrAFyJyQ8Ic1booitWhDLkSgDO gDqw+6+5yi+0NkaHkJzsBELzN4XsAW99z+G9rcsGBgFTkXJA6b2ovJjD84ys/qwRk0f0XzbGHPm24 080tCco/JvKsjW0VZIw2RGxroF6RecqWWEQvy7hOiVAjlRcJq8HH+7f8r3pChkA0SLgth4ZiIZeEu c6ZyZPUTEup6pYd9MRSA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWQ6U-0005Tr-Et; Wed, 06 May 2020 19:53:14 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWQ5P-00045e-Cg for linux-arm-kernel@lists.infradead.org; Wed, 06 May 2020 19:52:08 +0000 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 33F88207DD; Wed, 6 May 2020 19:52:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588794725; bh=ZyomlCpuKdUoICLzokR0IbvZQjWsbt/STt1gGfVlAGw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UNVpkMKkMacihStPGlQbeLbLyn1pE02CQUBiyOVbI2aMjRNiTrPTy5YJq+V0Uuh5s mxIfxDZK/FbTToxk2fgE6CCragrm5cbTCoNVKhqWBttAIRL1Ho3cs0NV/ynwXVQTIz z2e1CvtIK1a9OZBormdzOz+0rOVd82FWFq7YDMjE= From: Mark Brown To: Vincenzo Frascino , Will Deacon , Catalin Marinas Subject: [PATCH v3 05/11] arm64: bpf: Annotate JITed code for BTI Date: Wed, 6 May 2020 20:51:32 +0100 Message-Id: <20200506195138.22086-6-broonie@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200506195138.22086-1-broonie@kernel.org> References: <20200506195138.22086-1-broonie@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200506_125207_508723_EBA95D78 X-CRM114-Status: GOOD ( 11.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kees Cook , Daniel Borkmann , Jean-Philippe Brucker , Mark Brown , Amit Kachhap , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org In order to extend the protection offered by BTI to all code executing in kernel mode we need to annotate JITed BPF code appropriately for BTI. To do this we need to add a landing pad to the start of each BPF function and also immediately after the function prologue if we are emitting a function which can be tail called. Jumps within BPF functions are all to immediate offsets and therefore do not require landing pads. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas --- arch/arm64/net/bpf_jit.h | 8 ++++++++ arch/arm64/net/bpf_jit_comp.c | 12 ++++++++++++ 2 files changed, 20 insertions(+) diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h index eb73f9f72c46..05b477709b5f 100644 --- a/arch/arm64/net/bpf_jit.h +++ b/arch/arm64/net/bpf_jit.h @@ -189,4 +189,12 @@ /* Rn & Rm; set condition flags */ #define A64_TST(sf, Rn, Rm) A64_ANDS(sf, A64_ZR, Rn, Rm) +/* HINTs */ +#define A64_HINT(x) aarch64_insn_gen_hint(x) + +/* BTI */ +#define A64_BTI_C A64_HINT(AARCH64_INSN_HINT_BTIC) +#define A64_BTI_J A64_HINT(AARCH64_INSN_HINT_BTIJ) +#define A64_BTI_JC A64_HINT(AARCH64_INSN_HINT_BTIJC) + #endif /* _BPF_JIT_H */ diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index cdc79de0c794..83fa475c6b42 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -171,7 +171,11 @@ static inline int epilogue_offset(const struct jit_ctx *ctx) #define STACK_ALIGN(sz) (((sz) + 15) & ~15) /* Tail call offset to jump into */ +#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) +#define PROLOGUE_OFFSET 8 +#else #define PROLOGUE_OFFSET 7 +#endif static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) { @@ -208,6 +212,10 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) * */ + /* BTI landing pad */ + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + emit(A64_BTI_C, ctx); + /* Save FP and LR registers to stay align with ARM64 AAPCS */ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); emit(A64_MOV(1, A64_FP, A64_SP), ctx); @@ -230,6 +238,10 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) cur_offset, PROLOGUE_OFFSET); return -1; } + + /* BTI landing pad for the tail call, done with a BR */ + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + emit(A64_BTI_J, ctx); } ctx->stack_size = STACK_ALIGN(prog->aux->stack_depth); -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel