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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1722509710; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=G8zwKo1vJeCXVNcPUIO30V+QA++T8zr8IARn3SXYY4Y=; b=7M8OEU7eTPZDiS/y6Ns4k7oBEGIYV6BCgkgvZXxfvGFu+0e6C/vy2gMMa+nxBWYygz9WMQ 6k3GvD7q9hwsQ6Rx8qu60zwZcFWwJb+8XcZim6Da63CepS22cYAdZ/6YHIB/WGeUg0pXJB npYbOWHOKwFlV2RngatgnEOjnEEJCk4= 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 39A931007; Thu, 1 Aug 2024 03:55:37 -0700 (PDT) Received: from e124191.cambridge.arm.com (e124191.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0C9023F5A1; Thu, 1 Aug 2024 03:55:07 -0700 (PDT) Date: Thu, 1 Aug 2024 11:55:02 +0100 From: Joey Gouly To: Dave Martin Cc: linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, aneesh.kumar@kernel.org, aneesh.kumar@linux.ibm.com, bp@alien8.de, broonie@kernel.org, catalin.marinas@arm.com, christophe.leroy@csgroup.eu, dave.hansen@linux.intel.com, hpa@zytor.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, maz@kernel.org, mingo@redhat.com, mpe@ellerman.id.au, naveen.n.rao@linux.ibm.com, npiggin@gmail.com, oliver.upton@linux.dev, shuah@kernel.org, szabolcs.nagy@arm.com, tglx@linutronix.de, will@kernel.org, x86@kernel.org, kvmarm@lists.linux.dev Subject: Re: [PATCH v4 13/29] arm64: convert protection key into vm_flags and pgprot values Message-ID: <20240801105502.GA841837@e124191.cambridge.arm.com> References: <20240503130147.1154804-1-joey.gouly@arm.com> <20240503130147.1154804-14-joey.gouly@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 7B7BE140025 X-Rspamd-Server: rspam01 X-Stat-Signature: xoi5dunj64ard1ky8n8am775ikw4jity X-HE-Tag: 1722509715-15750 X-HE-Meta: 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 rVwdRkEO 8JqOoJUpF7kVaig9pyxa6BGowE1pqmr40I006xFclZO1cjD+Nkb70meXFxgSWHCXUIKhFvmvg81YOhvbEH6VJ84sMO3684pBlHdy7aV1QJs3YSDovUY8lFZx9a2XjrpWSE+XVFMSJz5lbzESbnaeWFgTsqoo7h1XExHfAGzF5yC0hjIjaQGPMHOOj2wdCm/2OQO9xI4GRPe1RwXju1u9ZURK7l8+REU2EEJF+2nT6EiQas3ayZyUDyXx11i7CBqDeacNoMHEpOFUy+5PakkcXPxz702i4XjVLWObAN4N5SpP0nb8YQez+4BfSfw== 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: List-Subscribe: List-Unsubscribe: On Thu, Jul 25, 2024 at 04:49:50PM +0100, Dave Martin wrote: > On Fri, May 03, 2024 at 02:01:31PM +0100, Joey Gouly wrote: > > Modify arch_calc_vm_prot_bits() and vm_get_page_prot() such that the pkey > > value is set in the vm_flags and then into the pgprot value. > > > > Signed-off-by: Joey Gouly > > Cc: Catalin Marinas > > Cc: Will Deacon > > --- > > arch/arm64/include/asm/mman.h | 8 +++++++- > > arch/arm64/mm/mmap.c | 9 +++++++++ > > 2 files changed, 16 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h > > index 5966ee4a6154..ecb2d18dc4d7 100644 > > --- a/arch/arm64/include/asm/mman.h > > +++ b/arch/arm64/include/asm/mman.h > > @@ -7,7 +7,7 @@ > > #include > > > > static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, > > - unsigned long pkey __always_unused) > > + unsigned long pkey) > > { > > unsigned long ret = 0; > > > > @@ -17,6 +17,12 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, > > if (system_supports_mte() && (prot & PROT_MTE)) > > ret |= VM_MTE; > > > > +#if defined(CONFIG_ARCH_HAS_PKEYS) > > + ret |= pkey & 0x1 ? VM_PKEY_BIT0 : 0; > > + ret |= pkey & 0x2 ? VM_PKEY_BIT1 : 0; > > + ret |= pkey & 0x4 ? VM_PKEY_BIT2 : 0; > > Out of interest, is this as bad as it looks or does the compiler turn > it into a shift and mask? Yeah, (gcc 13.2) produces good code here (this is do_mprotect_pkey after removing a lot of branching): and w0, w0, #0x7 orr x1, x1, x0, lsl #32 > > > > +#endif > > + > > return ret; > > } > > #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) > > diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c > > index 642bdf908b22..86eda6bc7893 100644 > > --- a/arch/arm64/mm/mmap.c > > +++ b/arch/arm64/mm/mmap.c > > @@ -102,6 +102,15 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags) > > if (vm_flags & VM_MTE) > > prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED); > > > > +#ifdef CONFIG_ARCH_HAS_PKEYS > > + if (vm_flags & VM_PKEY_BIT0) > > + prot |= PTE_PO_IDX_0; > > + if (vm_flags & VM_PKEY_BIT1) > > + prot |= PTE_PO_IDX_1; > > + if (vm_flags & VM_PKEY_BIT2) > > + prot |= PTE_PO_IDX_2; > > +#endif > > + > > Ditto. At least we only have three bits to cope with either way. > > I'm guessing that these functions are not super-hot path. > > [...] > > Cheers > ---Dave