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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5105AC369AB for ; Mon, 21 Apr 2025 05:54:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=sa9W+aozuagnVMGavt8BD4E0bLb+ctNBwuEsBHD99UM=; b=txSIi0lqIE//U4l2az34pIfYOf DUKSSccUWzZ/dLWuSgIJk3PSXXzflC/+aLHoDCWgYdWZiMngI9wVX2Trxxnhzj3jUyQOc2mzohGa5 LowhLYrtPL9o73EU8ApmG+hSXqkIehSFIabL/xwDVKbDuPKWqfHN2RCkdjo2VdPl1AVZjk80LBiKO s9qDlQNahfSUUqL6T1rSw3iKdlM9wPhmXDrTWax/zNZUOOI7dfSSclKURLAHKedTBHd0XQslq6o3L 1jFiNkOMcPPH2/32EWVsEogiBfw8IEYNXwlcxm6FU01IKNWP8qKOAqGkm1nB7H7xfHZb7zUrL6s8/ MkuR6hhA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u6k6k-00000003f1Q-1DF0; Mon, 21 Apr 2025 05:54:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u6k4s-00000003esi-48uS for linux-arm-kernel@lists.infradead.org; Mon, 21 Apr 2025 05:52:24 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CD01A339; Sun, 20 Apr 2025 22:52:15 -0700 (PDT) Received: from a077893.blr.arm.com (unknown [10.162.16.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 90EEB3F59E; Sun, 20 Apr 2025 22:52:17 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Will Deacon , Mark Rutland , Catalin Marinas , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] arm64/ptrace: Make user_hwdebug_state.dbg_regs[] array size as ARM_MAX_BRP Date: Mon, 21 Apr 2025 11:22:12 +0530 Message-Id: <20250421055212.123774-1-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250420_225223_114527_33FB359C X-CRM114-Status: GOOD ( 17.99 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Array elements inside 'struct user_hwdebug_state.dbg_regs[]' are inherently coupled with maximum breakpoints or watchpoints which could be present on a platform and which are defined with macros ARM_MAX_[BRP|WRP]. Rather than explicitly trying to keep the array elements in sync with these macros and then adding a BUILD_BUG_ON() just to ensure continued compliance , move these two macros into the uapi ptrace header itself thus making them available both for user space and kernel. While here also ensure that ARM_MAX_BRP and ARM_MAX_WRP are always the same via a new BUILD_BUG_ON(). This helps in making sure that user_hwdebug_state structure remains usable both for breakpoint and watchpoint registers set via ptrace() system call interface. Cc: Will Deacon Cc: Mark Rutland Cc: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org Cc: linux-perf-users@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- This patch applies on v6.15-rc3 arch/arm64/include/asm/hw_breakpoint.h | 7 ------- arch/arm64/include/uapi/asm/ptrace.h | 10 +++++++++- arch/arm64/kernel/hw_breakpoint.c | 9 +++++++++ 3 files changed, 18 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h index bd81cf17744a..63c21b515647 100644 --- a/arch/arm64/include/asm/hw_breakpoint.h +++ b/arch/arm64/include/asm/hw_breakpoint.h @@ -75,13 +75,6 @@ static inline void decode_ctrl_reg(u32 reg, #define ARM_KERNEL_STEP_ACTIVE 1 #define ARM_KERNEL_STEP_SUSPEND 2 -/* - * Limits. - * Changing these will require modifications to the register accessors. - */ -#define ARM_MAX_BRP 16 -#define ARM_MAX_WRP 16 - /* Virtual debug register bases. */ #define AARCH64_DBG_REG_BVR 0 #define AARCH64_DBG_REG_BCR (AARCH64_DBG_REG_BVR + ARM_MAX_BRP) diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index 0f39ba4f3efd..8683f541a467 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -99,6 +99,14 @@ struct user_fpsimd_state { __u32 __reserved[2]; }; +/* + * Maximum number of breakpoint and watchpoint registers + * on the platform. These macros get used both in kernel + * and user space as well. + */ +#define ARM_MAX_BRP 16 +#define ARM_MAX_WRP 16 + struct user_hwdebug_state { __u32 dbg_info; __u32 pad; @@ -106,7 +114,7 @@ struct user_hwdebug_state { __u64 addr; __u32 ctrl; __u32 pad; - } dbg_regs[16]; + } dbg_regs[ARM_MAX_BRP]; /* Or ARM_MAX_WRP */ }; /* SVE/FP/SIMD state (NT_ARM_SVE & NT_ARM_SSVE) */ diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index 722ac45f9f7b..9bc51682713d 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -981,6 +981,15 @@ static int __init arch_hw_breakpoint_init(void) { int ret; + /* + * Maximum supported breakpoint and watchpoint registers must + * always be the same - regardless of actual register numbers + * found on a given platform. This is because the user facing + * ptrace structure 'user_hwdebug_state' actually depends on + * these macros to be the same. + */ + BUILD_BUG_ON(ARM_MAX_BRP != ARM_MAX_WRP); + core_num_brps = get_num_brps(); core_num_wrps = get_num_wrps(); -- 2.25.1