Received: by 10.223.176.5 with SMTP id f5csp2751289wra; Thu, 1 Feb 2018 05:36:06 -0800 (PST) X-Google-Smtp-Source: AH8x225rEmib9jyqo63+XjPUTRLqu5NC0c9EQSrGwCFHMor+agtsh3EbtkGg5xZcE7XBgsxlwJAf X-Received: by 10.99.191.78 with SMTP id i14mr30241563pgo.246.1517492166600; Thu, 01 Feb 2018 05:36:06 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1517492166; cv=none; d=google.com; s=arc-20160816; b=vaaTVZuD9smVq0VA0sME+BKZ+1YKbcFEy97YrUWA+wC0rFta7VZoyRA/AH2ULgb+ab 90clPg0SFnNPnDscTASYpJ15jDVE6R9zAd2lkuEsM+oC8qKacXTix1vvQqkn4gR/tYcm qEkY/ELjDQljRU0ZuZJJN4c878MTKx5aENyJrD5Q6axlhIi0bDorC3huGwZ1gOhkjAWk bsyqyQ9P4TXiPYI68wYvnI77hK8rdXi4YB7ouvr7jDFKS5sWbahAWD191MUgjGlc21gb B5/s3GEHw+dl359W8A1sFaDGL6cYqoiVIpTppkHeWMKcAdAteU0hFNK3nDhkCmOK40k1 SekQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:from:references:cc:to:subject:arc-authentication-results; bh=CaSqiatu5I9gKQpcQvh5MXTwQRBlI+KyKQcwJtF53rM=; b=Y4YxG+PLmu/JvLJpmKhWJ8DLhA+Ua2E08seZ6NW0JS3skstcFPiC5VjdmqDEp7Qexn w/IWQV/qZbbTxwfQad8yAzeFI/WXovUtc+yduvSjHfFzmu7PbIsdEZxV6rQCIBwe/VuV loRkBy688pZn/LkaCVrxOK60ZyWoQQJcOKelMRRfa1v8pXR8GrCFwjqDBs2d+WvpVfyD bDVYceO4z1Zmc7oGRxsFyYJRyocLkgv7ifczQUYvTPi1podF289wJBRqoHvYipVr2IPT 3aBLtpC/j9KdK0vLHCrtnc0LqihGdrn/OBBRHh/F4mJ+UJCa846CgJM4oxpJ2FDMkOlv Fxxw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t10si4058772pfk.153.2018.02.01.05.35.51; Thu, 01 Feb 2018 05:36:06 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752105AbeBANe4 (ORCPT + 99 others); Thu, 1 Feb 2018 08:34:56 -0500 Received: from foss.arm.com ([217.140.101.70]:50344 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751467AbeBANez (ORCPT ); Thu, 1 Feb 2018 08:34:55 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9BEA580D; Thu, 1 Feb 2018 05:34:54 -0800 (PST) Received: from [10.1.210.88] (e110467-lin.cambridge.arm.com [10.1.210.88]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 934CA3F25C; Thu, 1 Feb 2018 05:34:51 -0800 (PST) Subject: Re: [PATCH v3 16/18] arm/arm64: smccc: Implement SMCCC v1.1 inline primitive To: Marc Zyngier , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Cc: Catalin Marinas , Will Deacon , Peter Maydell , Christoffer Dall , Lorenzo Pieralisi , Mark Rutland , Ard Biesheuvel , Andrew Jones , Hanjun Guo , Jayachandran C , Jon Masters , Russell King - ARM Linux References: <20180201114657.7323-1-marc.zyngier@arm.com> <20180201114657.7323-17-marc.zyngier@arm.com> From: Robin Murphy Message-ID: <6082f2bf-58be-8493-013e-e27f5a0d2570@arm.com> Date: Thu, 1 Feb 2018 13:34:50 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180201114657.7323-17-marc.zyngier@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/02/18 11:46, Marc Zyngier wrote: > One of the major improvement of SMCCC v1.1 is that it only clobbers > the first 4 registers, both on 32 and 64bit. This means that it > becomes very easy to provide an inline version of the SMC call > primitive, and avoid performing a function call to stash the > registers that would otherwise be clobbered by SMCCC v1.0. > > Signed-off-by: Marc Zyngier > --- > include/linux/arm-smccc.h | 143 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 143 insertions(+) > > diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h > index dd44d8458c04..575aabe85905 100644 > --- a/include/linux/arm-smccc.h > +++ b/include/linux/arm-smccc.h > @@ -150,5 +150,148 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1, > > #define arm_smccc_hvc_quirk(...) __arm_smccc_hvc(__VA_ARGS__) > > +/* SMCCC v1.1 implementation madness follows */ > +#ifdef CONFIG_ARM64 > + > +#define SMCCC_SMC_INST "smc #0" > +#define SMCCC_HVC_INST "hvc #0" Nit: Maybe the argument can go in the template and we just define the instruction mnemonics here? > + > +#endif > + > +#ifdef CONFIG_ARM #elif ? > +#include > +#include > + > +#define SMCCC_SMC_INST __SMC(0) > +#define SMCCC_HVC_INST __HVC(0) Oh, I see, it was to line up with this :( I do wonder if we could just embed an asm(".arch armv7-a+virt\n") (if even necessary) for ARM, then take advantage of the common mnemonics for all 3 instruction sets instead of needing manual encoding tricks? I don't think we should ever be pulling this file in for non-v7 builds. I suppose that strictly that appears to need binutils 2.21 rather than the offical supported minimum of 2.20, but are people going to be throwing SMCCC configs at antique toolchains in practice? > + > +#endif > + > +#define ___count_args(_0, _1, _2, _3, _4, _5, _6, _7, _8, x, ...) x > + > +#define __count_args(...) \ > + ___count_args(__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0) > + > +#define __constraint_write_0 \ > + "+r" (r0), "=&r" (r1), "=&r" (r2), "=&r" (r3) > +#define __constraint_write_1 \ > + "+r" (r0), "+r" (r1), "=&r" (r2), "=&r" (r3) > +#define __constraint_write_2 \ > + "+r" (r0), "+r" (r1), "+r" (r2), "=&r" (r3) > +#define __constraint_write_3 \ > + "+r" (r0), "+r" (r1), "+r" (r2), "+r" (r3) > +#define __constraint_write_4 __constraint_write_3 > +#define __constraint_write_5 __constraint_write_4 > +#define __constraint_write_6 __constraint_write_5 > +#define __constraint_write_7 __constraint_write_6 > + > +#define __constraint_read_0 > +#define __constraint_read_1 > +#define __constraint_read_2 > +#define __constraint_read_3 > +#define __constraint_read_4 "r" (r4) > +#define __constraint_read_5 __constraint_read_4, "r" (r5) > +#define __constraint_read_6 __constraint_read_5, "r" (r6) > +#define __constraint_read_7 __constraint_read_6, "r" (r7) > + > +#define __declare_arg_0(a0, res) \ > + struct arm_smccc_res *___res = res; \ Looks like the declaration of ___res could simply be factored out to the template... > + register u32 r0 asm("r0") = a0; \ > + register unsigned long r1 asm("r1"); \ > + register unsigned long r2 asm("r2"); \ > + register unsigned long r3 asm("r3") > + > +#define __declare_arg_1(a0, a1, res) \ > + struct arm_smccc_res *___res = res; \ > + register u32 r0 asm("r0") = a0; \ > + register typeof(a1) r1 asm("r1") = a1; \ > + register unsigned long r2 asm("r2"); \ > + register unsigned long r3 asm("r3") > + > +#define __declare_arg_2(a0, a1, a2, res) \ > + struct arm_smccc_res *___res = res; \ > + register u32 r0 asm("r0") = a0; \ > + register typeof(a1) r1 asm("r1") = a1; \ > + register typeof(a2) r2 asm("r2") = a2; \ > + register unsigned long r3 asm("r3") > + > +#define __declare_arg_3(a0, a1, a2, a3, res) \ > + struct arm_smccc_res *___res = res; \ > + register u32 r0 asm("r0") = a0; \ > + register typeof(a1) r1 asm("r1") = a1; \ > + register typeof(a2) r2 asm("r2") = a2; \ > + register typeof(a3) r3 asm("r3") = a3 > + > +#define __declare_arg_4(a0, a1, a2, a3, a4, res) \ > + __declare_arg_3(a0, a1, a2, a3, res); \ > + register typeof(a4) r4 asm("r4") = a4 > + > +#define __declare_arg_5(a0, a1, a2, a3, a4, a5, res) \ > + __declare_arg_4(a0, a1, a2, a3, a4, res); \ > + register typeof(a5) r5 asm("r5") = a5 > + > +#define __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res) \ > + __declare_arg_5(a0, a1, a2, a3, a4, a5, res); \ > + register typeof(a6) r6 asm("r6") = a6 > + > +#define __declare_arg_7(a0, a1, a2, a3, a4, a5, a6, a7, res) \ > + __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res); \ > + register typeof(a7) r7 asm("r7") = a7 > + > +#define ___declare_args(count, ...) __declare_arg_ ## count(__VA_ARGS__) > +#define __declare_args(count, ...) ___declare_args(count, __VA_ARGS__) > + > +#define ___constraints(count) \ > + : __constraint_write_ ## count \ > + : __constraint_read_ ## count \ > + : "memory" > +#define __constraints(count) ___constraints(count) > + > +/* > + * We have an output list that is not necessarily used, and GCC feels > + * entitled to optimise the whole sequence away. "volatile" is what > + * makes it stick. > + */ > +#define __arm_smccc_1_1(inst, ...) \ > + do { \ > + __declare_args(__count_args(__VA_ARGS__), __VA_ARGS__); \ > + asm volatile(inst "\n" \ > + __constraints(__count_args(__VA_ARGS__))); \ > + if (___res) \ > + *___res = (typeof(*___res)){r0, r1, r2, r3}; \ ...especially since there's no obvious indication of where it comes from when you're looking here. Otherwise, though, this has already turned out pretty sleek; Reviewed-by: Robin Murphy > + } while (0) > + > +/* > + * arm_smccc_1_1_smc() - make an SMCCC v1.1 compliant SMC call > + * > + * This is a variadic macro taking one to eight source arguments, and > + * an optional return structure. > + * > + * @a0-a7: arguments passed in registers 0 to 7 > + * @res: result values from registers 0 to 3 > + * > + * This macro is used to make SMC calls following SMC Calling Convention v1.1. > + * The content of the supplied param are copied to registers 0 to 7 prior > + * to the SMC instruction. The return values are updated with the content > + * from register 0 to 3 on return from the SMC instruction if not NULL. > + */ > +#define arm_smccc_1_1_smc(...) __arm_smccc_1_1(SMCCC_SMC_INST, __VA_ARGS__) > + > +/* > + * arm_smccc_1_1_hvc() - make an SMCCC v1.1 compliant HVC call > + * > + * This is a variadic macro taking one to eight source arguments, and > + * an optional return structure. > + * > + * @a0-a7: arguments passed in registers 0 to 7 > + * @res: result values from registers 0 to 3 > + * > + * This macro is used to make HVC calls following SMC Calling Convention v1.1. > + * The content of the supplied param are copied to registers 0 to 7 prior > + * to the HVC instruction. The return values are updated with the content > + * from register 0 to 3 on return from the HVC instruction if not NULL. > + */ > +#define arm_smccc_1_1_hvc(...) __arm_smccc_1_1(SMCCC_HVC_INST, __VA_ARGS__) > + > #endif /*__ASSEMBLY__*/ > #endif /*__LINUX_ARM_SMCCC_H*/ >