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 7872BC3DA49 for ; Wed, 17 Jul 2024 02:05:44 +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-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=i8QRegxtd6+FgIkF6diGK9DWIR0YDnVslVz04u7ogUM=; b=eDzfs6efMUvsXcSiBGzkPPFXyH 7CbU1KJ8GN7VyR3Ewqm54PmXFgiHJgzSGqxZiQPRhnjBLQX4gsHbAwciEXH3oHr/7hyUfQ95Fp66f Pjwp+0QZU13Xgqgv2ameZucKa5QjlB9/hHk8cMxhjK6hnKBimuozT9dxszYauhinRRlAxRuiFbdWg l5whTu2jO0wV7QD9UMVvw7GydkUsV/1VYl7klQN3MtS/3IdMe+Zt+02Qjou5Or0F/EWBmHtQ4grrF LI/4TFAVBVrq38+xWFMUMmyxUwEjCjj56C9VVbZMYQf2HtDviRngqhAzPukpkDOmkYfuLIHgND8ok 7ot4JFCA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sTu2s-0000000CKFp-0I8j; Wed, 17 Jul 2024 02:05:30 +0000 Received: from mail-pf1-x434.google.com ([2607:f8b0:4864:20::434]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sTu2W-0000000CK92-4AQh for linux-arm-kernel@lists.infradead.org; Wed, 17 Jul 2024 02:05:10 +0000 Received: by mail-pf1-x434.google.com with SMTP id d2e1a72fcca58-70b42250526so4690199b3a.1 for ; Tue, 16 Jul 2024 19:05:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1721181908; x=1721786708; darn=lists.infradead.org; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:from:to:cc:subject:date:message-id:reply-to; bh=i8QRegxtd6+FgIkF6diGK9DWIR0YDnVslVz04u7ogUM=; b=E96BtvkICgmd1MkCA5yJ+JNi9Bqya0l9o49l7c0GdZ8tE1NtOLS5ihyVyC1XWyKSZf gRiv3RyQ+ZAywl8W+CO2aRcrWjnxpPpdeZlM2hbHRE2m3sHa1WM5SSwDJhnLJ3agCFXu T1ksqNZVx1sVB7ZQ5oqxpJ8murIGKK1gyF8S25LUG5T5hJatmCWUOjNm0fZ2EHHuNOmI CYM6Op1Cc9jVT+dDmrjaWLDjUkJmBkj+yi028B9JF1pLcP58goM1TxhcNe/8AJA+r3xv aBznj8Q2+AtI4GFDtq2Sr1wxiEffZomTGC2L6rt2mdoZ02NHA5WY83zALLL9QUu3ALZ9 Ho5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721181908; x=1721786708; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=i8QRegxtd6+FgIkF6diGK9DWIR0YDnVslVz04u7ogUM=; b=HuQKZfFcIcU489HZ5yVtVowVLCijt5nJaD/jRr2q1HpMhOUseZNJXEg6xG8tMMv8Cw VW36mbbJVWg9vRDfwVej+ca2Ec5ZWuzL28ffqrhcI0/XITvY0RcL45xT5eEAeTDGzm7j yzIoUOiFfl2UPzqeQrMB/e+j+/dmO65g1S+kEJ2qQZrpTpD2JyIMPa8wcbz0WjOPDsbp gxTS6yDbWTPdHDQoA8XPbBzvHHra3FthGbDVJP0zsjFQoGqBsW6dy3N2WjRbM1pdcYot iWH09+QFsJYTzRzE/aUxPK0xFvfLnVmfUYoVhFzyZqZ3OvxdQfcGRTSfZBn4qnaeLRHR ZiPA== X-Forwarded-Encrypted: i=1; AJvYcCVoctcXL9YpqR23RYzuJbTK053owW/gVMf3sGHavGMvaBQX9caBfg44sCkJdbHFcCny/BgMApjHdXBCJHF1fVpvszMwEFjkunqYioV0mM7MkqI5BMM= X-Gm-Message-State: AOJu0YzUpmuMffQ+CmzPVHgbpaTTinAkrz3MQjN7RAvl+HusZwG8k0qu C9RHOCQ/rCwBiAMc5imcvw81u9d4m8Zcw95Cug38fA+bRahABZ7tzKDop/l33lg= X-Google-Smtp-Source: AGHT+IE2KzNPcTth+gMo267NV2Jd+oHot7f6l6m3xb5YAhTJAAFsLZacsEiGAChpR0B8dRp+Zw50zg== X-Received: by 2002:a05:6a21:710a:b0:1c2:8e3f:a49 with SMTP id adf61e73a8af0-1c3fdcc006fmr450858637.3.1721181907982; Tue, 16 Jul 2024 19:05:07 -0700 (PDT) Received: from localhost ([2804:14d:7e39:8470:4ae3:bddc:48f7:36a0]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2caedbf733esm7067534a91.20.2024.07.16.19.05.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jul 2024 19:05:07 -0700 (PDT) From: Thiago Jung Bauermann To: Mark Brown Cc: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy , Kees Cook , "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Ross Burton , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v9 20/39] arm64/gcs: Ensure that new threads have a GCS In-Reply-To: <20240625-arm64-gcs-v9-20-0f634469b8f0@kernel.org> (Mark Brown's message of "Tue, 25 Jun 2024 15:57:48 +0100") References: <20240625-arm64-gcs-v9-0-0f634469b8f0@kernel.org> <20240625-arm64-gcs-v9-20-0f634469b8f0@kernel.org> Date: Tue, 16 Jul 2024 23:05:04 -0300 Message-ID: <87bk2wu627.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240716_190509_249063_69B2B2B7 X-CRM114-Status: GOOD ( 15.89 ) 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 Mark Brown writes: > diff --git a/arch/arm64/mm/gcs.c b/arch/arm64/mm/gcs.c > index b0a67efc522b..4a3ce8e3bdfb 100644 > --- a/arch/arm64/mm/gcs.c > +++ b/arch/arm64/mm/gcs.c > @@ -8,6 +8,139 @@ > #include > #include > > +static unsigned long alloc_gcs(unsigned long addr, unsigned long size, > + unsigned long token_offset, bool set_res_tok) The token_offset and set_res_tok arguments aren't used in this function, so they can be removed. > +{ > + int flags = MAP_ANONYMOUS | MAP_PRIVATE; > + struct mm_struct *mm = current->mm; > + unsigned long mapped_addr, unused; > + > + if (addr) > + flags |= MAP_FIXED_NOREPLACE; > + > + mmap_write_lock(mm); > + mapped_addr = do_mmap(NULL, addr, size, PROT_READ | PROT_WRITE, flags, > + VM_SHADOW_STACK, 0, &unused, NULL); > + mmap_write_unlock(mm); > + > + return mapped_addr; > +} > + > +static unsigned long gcs_size(unsigned long size) > +{ > + if (size) > + return PAGE_ALIGN(size); > + > + /* Allocate RLIMIT_STACK/2 with limits of PAGE_SIZE..2G */ > + size = PAGE_ALIGN(min_t(unsigned long long, > + rlimit(RLIMIT_STACK) / 2, SZ_2G)); > + return max(PAGE_SIZE, size); > +} > + > +static bool gcs_consume_token(struct mm_struct *mm, unsigned long user_addr) > +{ > + u64 expected = GCS_CAP(user_addr); > + u64 val; > + int ret; > + > + /* This should really be an atomic cpmxchg. It is not. */ s/cpmxchg/cmpxchg/ The same typo is also in arch/x86/kernel/shstk.c, from the "fork: Support shadow stacks in clone3()" patch series. > + ret = access_remote_vm(mm, user_addr, &val, sizeof(val), > + FOLL_FORCE); > + if (ret != sizeof(val)) > + return false; > + > + if (val != expected) > + return false; > + > + val = 0; > + ret = access_remote_vm(mm, user_addr, &val, sizeof(val), > + FOLL_FORCE | FOLL_WRITE); > + if (ret != sizeof(val)) > + return false; > + > + return true; > +} -- Thiago