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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UYNM6X2zqA6tod+6SjIBW+v6Liwy/ak5LM2gfcF+mXgLfmpQRUpi3xtLiAnTZwdnE pgnAmIpBhiaiN/fvEhj7GZ1T7dsaMhZgszRdRQ4l0RGyAg918/p2d0WlL/uqhcUtTx /asFjuJQcod+c5gT+rGYBCsQ+UeWK4ZxUu1QSuog= Date: Tue, 1 Sep 2026 20:03:38 +0530 From: Linu Cherian To: Kevin Brodsky Cc: linux-hardening@vger.kernel.org, Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?iso-8859-1?Q?Pierre-Cl=E9ment?= Tosi , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner Subject: Re: [PATCH RFC v9 02/25] set_memory: Introduce set_memory_pkey() stub Message-ID: References: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> <20260818-kpkeys-v9-2-743ad31b2c8f@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260818-kpkeys-v9-2-743ad31b2c8f@arm.com> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 376FEC0010 X-Stat-Signature: 5mwzwim1kk31kqc7oku6cwqg9jn9ehwj X-HE-Tag: 1788273223-829297 X-HE-Meta: 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 do+wlI4o t2mGT2NnMEd77gQir00nHJVvL7VBpTBaPbtpeUUY8dP49KBns0y4rP596woIQd0xI1AcQ6OX2WHVJWFZtMfw5jfbAE/WRQe2i+fMn/tYIuPRVEoXbFz5scyBy2DmUT03opbo3y+3Ez7WHP17hMMCQB1QhqdsxcmSsRRGjRiqmg7V5D2SElfzIPLJ7+e0zPE/nTLLsS3zFIlGQoJENh1JzxluDvDuyuIqru8+vkYrJUNB7cTienx+tYo2ngiFqdKAGDPANSeQuySelEEBFTEBlXSC7sOIIjFiYfuNRkLd20ksGVPsuLAx6bPkBCnsaMHyPmPS9cAsiMb30sY/6Ub+YEg6PE14FGFiMYWGJYlTR7A3fLfVwp0dIUzYV9wrYJO2P+AcO Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Kevin, On Tue, Aug 18, 2026 at 03:08:44PM +0100, Kevin Brodsky wrote: > Introduce a new function, set_memory_pkey(), which sets the > protection key (pkey) of pages in the specified linear mapping > range. Architectures implementing kernel pkeys (kpkeys) must > provide a suitable implementation; an empty stub is added as Could you make it explicit here why we are restricting this only to the linear mapping range ? Would be helpful to add the reasoning in the commit message and as comments. Essentially we are also making a assumption here that there are no aliases to the linear map ? > fallback. > > Signed-off-by: Kevin Brodsky > --- > include/linux/set_memory.h | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h > index 3030d9245f5a..7b3a8bfde3c6 100644 > --- a/include/linux/set_memory.h > +++ b/include/linux/set_memory.h > @@ -84,4 +84,11 @@ static inline int set_memory_decrypted(unsigned long addr, int numpages) > } > #endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */ > > +#ifndef CONFIG_ARCH_HAS_KPKEYS > +static inline int set_memory_pkey(unsigned long addr, int numpages, int pkey) > +{ > + return 0; > +} > +#endif Would be better to make this (linar map range)constraint on the API name or that passed as a boolean flag ? Also, it would be better to have the __is_lm_address checks in this generic wrapper which then calls arch_set_memory_pkey ? -- Linu Cherian