From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f181.google.com (mail-pf1-f181.google.com [209.85.210.181]) by sourceware.org (Postfix) with ESMTPS id 5042D3858C29 for ; Tue, 6 Feb 2024 17:06:20 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 5042D3858C29 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=gcc.gnu.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 5042D3858C29 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=209.85.210.181 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1707239182; cv=none; b=KNqFfDN3z8queH387vHzq4l4qK9NjprQu+884SRyXx/DlrL/7bumGG5jISmufS1UkeMWmIfqYG/Ds+m4VhhGPkFSgZF3vFH78/V1pb6eqZzh8hpVgyVhMKFN+kTz6vsTkhSxvEQwc41ELmUz/JTavaD2JdGw3HU2w5E6LaaV3lo= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1707239182; c=relaxed/simple; bh=+fnlN91qawTZT2xnqtA1Hqb1ly3R6s0Hhs+t6nY6gzI=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=An8+wDO6+sH0jpxHeCb+j6q8yrQJYzuWy1detBCK7ZIbQSquzcjapWfmbHAci+iFtsGIILaZC7yP+fbx7cgdyiODQXKamEJjCaSkL26liORlBkyKW2tMP96xBvE4GaTO7lBnYD/1iTmiHWNN4y7+ztfdOj6ezXQMh8CCP96JoW4= ARC-Authentication-Results: i=1; server2.sourceware.org Received: by mail-pf1-f181.google.com with SMTP id d2e1a72fcca58-6e038bdf6b1so1788270b3a.3 for ; Tue, 06 Feb 2024 09:06:20 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707239179; x=1707843979; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=J2GrSNV4t2MVFqSdx9UT04/0nMISwutYvWnYHoc2dJE=; b=DyPp5Y/rQZj4pUOLQ3nUNHYarFcl9XVRjlFcKQPXk5Cu/OHam9BYcePJAU0cwcTqus XeI9GaEbFXVjrmBYNUY7jYx0K2hc9/DPmSQ1NXhNQxnDjAkUIgjtTcKZhV3MoNVP9iU1 8B5XZeLPtuBBQauu6MLCKCnhNMFQuedQ9izPj4wCXidc+5yRjK2FfL3SuyHHtZSKFhfT ZQCuYVEckHHzUqU+aQO2NpEET2wyL5X7KH1PoSiwj9kDRAsVIjkostBdHqcSCFjRMxsM /WCLOIbIQ985+bmRq8BHwlWPJ9n+Z8Ub5L0Rjsxlg9tBssyHjScfGUOalLfJz7Fe34/x 36Qw== X-Gm-Message-State: AOJu0YzlNRznyJ8euPhY1jsalVQg3XQ+7ixrzCXhaTW7W1Z+9N57AD6i YWHpahN7EySSHXznFj0GpAITgplpq0xlg7KkcQFJf4OWIMsefMEO X-Google-Smtp-Source: AGHT+IG4Sh90HMK4O4BOQAly6/zKR3tm+EoWnJMjQId6x26a4Pl5zxWE+G5Nwg7lGVRMyyu669+nsA== X-Received: by 2002:aa7:8490:0:b0:6e0:42de:c8d6 with SMTP id u16-20020aa78490000000b006e042dec8d6mr142313pfn.14.1707239150770; Tue, 06 Feb 2024 09:05:50 -0800 (PST) X-Forwarded-Encrypted: i=0; AJvYcCW9Ed00DI8ps/IGEpVKeQ9fn5CetFXQWUnKR7OQElhEIIiVYPJpLLsgoZ9sYP5M+/1gzjMHyCBxWGV8oi+DCeY/p/WCYnvPgmC9f8XhuRwfN6/yDhD5 Received: from localhost.localdomain ([149.248.38.156]) by smtp.gmail.com with ESMTPSA id jw16-20020a056a00929000b006db05eb1301sm2196559pfb.21.2024.02.06.09.05.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Feb 2024 09:05:50 -0800 (PST) From: YunQiang Su To: nickc@redhat.com Cc: binutils@sourceware.org, macro@orcam.me.uk, xry111@xry111.site Subject: [PATCH v4] MIPS/Gas: Disallow branch to absolute address for PIC Date: Wed, 7 Feb 2024 01:05:38 +0800 Message-Id: <20240206170538.2937169-1-syq@gcc.gnu.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-11.0 required=5.0 tests=BAYES_00,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,GIT_PATCH_0,HEADER_FROM_DIFFERENT_DOMAINS,KAM_DMARC_STATUS,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: The asm code like b (0) will generate binary like: 00000000 <.text>: 0: 1000ffff b 0x0 0: R_MIPS_PC16 *ABS* 4: 00000000 nop If this object is linked into an PIC/PIC dynamic executable, this branch instruction will jump to a wrong address, with low 16bit unset. Maybe we need a new dynamic relocation, which is not even defined by MIPS psABI, and I don't think that it is worth at all. See PR31343. --- gas/config/tc-mips.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/gas/config/tc-mips.c b/gas/config/tc-mips.c index 43c12de2c8a..f3f5c1f469d 100644 --- a/gas/config/tc-mips.c +++ b/gas/config/tc-mips.c @@ -7560,6 +7560,9 @@ append_insn (struct mips_cl_insn *ip, expressionS *address_expr, ip->insn_opcode |= ((address_expr->X_add_number >> shift) & 0xffff); } + if (mips_pic != NO_PIC && address_expr->X_op == O_constant) + as_bad (_("PIC code branch to absolute address (0x%lx)"), + (unsigned long) address_expr->X_add_number); } break; @@ -7577,6 +7580,9 @@ append_insn (struct mips_cl_insn *ip, expressionS *address_expr, (unsigned long) address_expr->X_add_number); ip->insn_opcode |= ((address_expr->X_add_number >> shift) & 0x1fffff); + if (mips_pic != NO_PIC && address_expr->X_op == O_constant) + as_bad (_("PIC code branch to absolute address (0x%lx)"), + (unsigned long) address_expr->X_add_number); } break; @@ -7594,6 +7600,9 @@ append_insn (struct mips_cl_insn *ip, expressionS *address_expr, (unsigned long) address_expr->X_add_number); ip->insn_opcode |= ((address_expr->X_add_number >> shift) & 0x3ffffff); + if (mips_pic != NO_PIC && address_expr->X_op == O_constant) + as_bad (_("PIC code branch to absolute address (0x%lx)"), + (unsigned long) address_expr->X_add_number); } break; -- 2.39.2