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Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMx9o-005pMK-8Z; Thu, 18 Mar 2021 18:14:04 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMx9j-005pKp-0S for linux-arm-kernel@lists.infradead.org; Thu, 18 Mar 2021 18:14:01 +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 56958101E; Thu, 18 Mar 2021 11:13:56 -0700 (PDT) Received: from [10.37.12.7] (unknown [10.37.12.7]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C0A993F70D; Thu, 18 Mar 2021 11:13:54 -0700 (PDT) Subject: Re: [PATCH 5/5] arm64: compat: Poison the compat sigpage To: Will Deacon , linux-arm-kernel@lists.infradead.org Cc: kernel-team@android.com, Catalin Marinas , Mark Rutland , Marc Zyngier , Russell King References: <20210318170738.7756-1-will@kernel.org> <20210318170738.7756-6-will@kernel.org> From: Vincenzo Frascino Message-ID: <9e50343c-bab2-653d-336a-5f87293071b6@arm.com> Date: Thu, 18 Mar 2021 18:13:53 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210318170738.7756-6-will@kernel.org> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210318_181359_233612_46CF732C X-CRM114-Status: GOOD ( 15.87 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 3/18/21 5:07 PM, Will Deacon wrote: > Commit 9c698bff66ab ("ARM: ensure the signal page contains defined contents") > poisoned the unused portions of the signal page for 32-bit Arm. > > Implement the same poisoning for the compat signal page on arm64 rather > than using __GFP_ZERO. > > Signed-off-by: Will Deacon Reviewed-by: Vincenzo Frascino > --- > arch/arm64/kernel/vdso.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c > index 16bf0b46fb70..159b72a646ab 100644 > --- a/arch/arm64/kernel/vdso.c > +++ b/arch/arm64/kernel/vdso.c > @@ -318,17 +318,20 @@ static int aarch32_alloc_kuser_vdso_page(void) > return 0; > } > > +#define COMPAT_SIGPAGE_POISON_WORD 0xe7fddef1 > static int aarch32_alloc_sigpage(void) > { > extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; > int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; > - unsigned long sigpage; > + __le32 poison = cpu_to_le32(COMPAT_SIGPAGE_POISON_WORD); > + void *sigpage; > > - sigpage = get_zeroed_page(GFP_KERNEL); > + sigpage = (void *)__get_free_page(GFP_KERNEL); > if (!sigpage) > return -ENOMEM; > > - memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz); > + memset32(sigpage, (__force u32)poison, PAGE_SIZE / sizeof(poison)); > + memcpy(sigpage, __aarch32_sigret_code_start, sigret_sz); > aarch32_sig_page = virt_to_page(sigpage); > return 0; > } > -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel