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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1pkjQc-000lmj-84; Fri, 07 Apr 2023 10:34:46 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id CC519300070; Fri, 7 Apr 2023 12:34:44 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B0C032625093E; Fri, 7 Apr 2023 12:34:44 +0200 (CEST) Date: Fri, 7 Apr 2023 12:34:44 +0200 From: Peter Zijlstra To: Ankur Arora Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com, willy@infradead.org, mgorman@suse.de, rostedt@goodmis.org, tglx@linutronix.de, vincent.guittot@linaro.org, jon.grimm@amd.com, bharata@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Subject: Re: [PATCH 5/9] x86/clear_pages: add clear_pages() Message-ID: <20230407103444.GB430894@hirez.programming.kicks-ass.net> References: <20230403052233.1880567-1-ankur.a.arora@oracle.com> <20230403052233.1880567-6-ankur.a.arora@oracle.com> <20230406082304.GE386572@hirez.programming.kicks-ass.net> <878rf4jz1x.fsf@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <878rf4jz1x.fsf@oracle.com> X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: tmy89xefz9ogeubo55ojd9g8w3quz1ge X-Rspamd-Queue-Id: 6EDE1A000C X-HE-Tag: 1680863698-643922 X-HE-Meta: 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 t9T213EI T6jcr7QaE/cXYzNIFDORSdEYSHZ9ULleKFfC8Er3W0C0Zo4wa/wAtBB+RtvtdW9EXvV/DCBFU8z/WQ2hbVz8+LjouukApJHUpwD3KLQoBO9MeQEt8Z6pWgsbNcOJQWHB1L+cD5xsKv0ELD+6rjO76Si074nlWmnHmbHPJM63Et3uQlvEzZkRcDSKSHJ2tT+VeWZZFOZHSOtAi7bXe1NHcXes/I7Mzhkg4x96h3C52S5mrnnpSxZjTc2sE31+UUjqpMn6jIYF0xK2o98B4bfpz2tTytA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Apr 06, 2023 at 05:50:18PM -0700, Ankur Arora wrote: > > Peter Zijlstra writes: > > > On Sun, Apr 02, 2023 at 10:22:29PM -0700, Ankur Arora wrote: > >> Add clear_pages() and define the ancillary clear_user_pages(). > >> > >> Signed-off-by: Ankur Arora > >> --- > >> arch/x86/include/asm/page.h | 6 ++++++ > >> arch/x86/include/asm/page_32.h | 6 ++++++ > >> arch/x86/include/asm/page_64.h | 9 +++++++-- > >> 3 files changed, 19 insertions(+), 2 deletions(-) > >> > >> diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h > >> index d18e5c332cb9..03e3c69fc427 100644 > >> --- a/arch/x86/include/asm/page.h > >> +++ b/arch/x86/include/asm/page.h > >> @@ -28,6 +28,12 @@ static inline void clear_user_page(void *page, unsigned long vaddr, > >> clear_page(page); > >> } > >> > >> +static inline void clear_user_pages(void *page, unsigned long vaddr, > >> + struct page *pg, unsigned int nsubpages) > >> +{ > >> + clear_pages(page, nsubpages); > >> +} > > > > This seems dodgy, clear_user* has slightly different semantics. It needs > > the access_ok() and stac/clac thing on at the very least. > > That can't be right. On x86, clear_user_page(), copy_user_page() (and > now the multi-page versions) only write to kernel maps of user pages. > That's why they can skip the access_ok(), stac/clac or uacess > exception handling. Bah, that namespace is a mess :/