From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 826ABC6FA82 for ; Fri, 9 Sep 2022 12:13:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231542AbiIIMNS convert rfc822-to-8bit (ORCPT ); Fri, 9 Sep 2022 08:13:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230170AbiIIMMv (ORCPT ); Fri, 9 Sep 2022 08:12:51 -0400 Received: from gloria.sntech.de (gloria.sntech.de [185.11.138.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FA843A160 for ; Fri, 9 Sep 2022 05:10:54 -0700 (PDT) Received: from ip5b412258.dynamic.kabel-deutschland.de ([91.65.34.88] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1oWcqS-0005AW-Cz; Fri, 09 Sep 2022 14:10:52 +0200 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Anup Patel Cc: linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org, Andrew Jones , linux-kernel@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, anup@brainfault.org, mchitale@ventanamicro.com Subject: Re: [PATCH v2 2/4] riscv: Introduce support for defining instructions Date: Fri, 09 Sep 2022 14:10:51 +0200 Message-ID: <2513607.d7IHhHJzqS@diego> In-Reply-To: References: <20220831172500.752195-1-ajones@ventanamicro.com> <3006889.o7ts2hSHzF@diego> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Freitag, 9. September 2022, 13:23:47 CEST schrieb Anup Patel: > On Thu, Sep 8, 2022 at 9:20 PM Heiko Stübner wrote: > > > > Am Mittwoch, 31. August 2022, 19:24:58 CEST schrieb Andrew Jones: > > > When compiling with toolchains that haven't yet been taught about > > > new instructions we need to encode them ourselves. Create a new file > > > where support for instruction definitions will evolve. We initiate > > > the file with a macro called INSN_R(), which implements the R-type > > > instruction encoding. INSN_R() will use the assembler's .insn > > > directive when available, which should give the assembler a chance > > > to do some validation. When .insn is not available we fall back to > > > manual encoding. > > > > > > Not only should using instruction encoding macros improve readability > > > and maintainability of code over the alternative of inserting > > > instructions directly (e.g. '.word 0xc0de'), but we should also gain > > > potential for more optimized code after compilation because the > > > compiler will have control over the input and output registers used. > > > > > > Signed-off-by: Andrew Jones > > > Reviewed-by: Anup Patel > > > --- > > > arch/riscv/Kconfig | 3 ++ > > > arch/riscv/include/asm/insn-def.h | 86 +++++++++++++++++++++++++++++++ > > > 2 files changed, 89 insertions(+) > > > create mode 100644 arch/riscv/include/asm/insn-def.h > > > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > > index ed66c31e4655..f8f3b316b838 100644 > > > --- a/arch/riscv/Kconfig > > > +++ b/arch/riscv/Kconfig > > > @@ -227,6 +227,9 @@ config RISCV_DMA_NONCOHERENT > > > select ARCH_HAS_SETUP_DMA_OPS > > > select DMA_DIRECT_REMAP > > > > > > +config AS_HAS_INSN > > > + def_bool $(as-instr,.insn r 51$(comma) 0$(comma) 0$(comma) t0$(comma) t0$(comma) zero) > > > + > > > source "arch/riscv/Kconfig.socs" > > > source "arch/riscv/Kconfig.erratas" > > > > > > diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h > > > new file mode 100644 > > > index 000000000000..2dcd1d4781bf > > > --- /dev/null > > > +++ b/arch/riscv/include/asm/insn-def.h > > > @@ -0,0 +1,86 @@ > > > +/* SPDX-License-Identifier: GPL-2.0-only */ > > > + > > > +#ifndef __ASM_INSN_DEF_H > > > +#define __ASM_INSN_DEF_H > > > + > > > +#include > > > + > > > +#define INSN_R_FUNC7_SHIFT 25 > > > +#define INSN_R_RS2_SHIFT 20 > > > +#define INSN_R_RS1_SHIFT 15 > > > +#define INSN_R_FUNC3_SHIFT 12 > > > +#define INSN_R_RD_SHIFT 7 > > > +#define INSN_R_OPCODE_SHIFT 0 > > > + > > > +#ifdef __ASSEMBLY__ > > > + > > > +#ifdef CONFIG_AS_HAS_INSN > > > + > > > + .macro insn_r, opcode, func3, func7, rd, rs1, rs2 > > > + .insn r \opcode, \func3, \func7, \rd, \rs1, \rs2 > > > + .endm > > > + > > > +#else > > > + > > > +#include > > > + > > > + .macro insn_r, opcode, func3, func7, rd, rs1, rs2 > > > + .4byte ((\opcode << INSN_R_OPCODE_SHIFT) | \ > > > + (\func3 << INSN_R_FUNC3_SHIFT) | \ > > > + (\func7 << INSN_R_FUNC7_SHIFT) | \ > > > + (.L__gpr_num_\rd << INSN_R_RD_SHIFT) | \ > > > + (.L__gpr_num_\rs1 << INSN_R_RS1_SHIFT) | \ > > > + (.L__gpr_num_\rs2 << INSN_R_RS2_SHIFT)) > > > + .endm > > > + > > > +#endif > > > + > > > +#define INSN_R(...) insn_r __VA_ARGS__ > > > + > > > +#else /* ! __ASSEMBLY__ */ > > > + > > > +#ifdef CONFIG_AS_HAS_INSN > > > + > > > +#define INSN_R(opcode, func3, func7, rd, rs1, rs2) \ > > > + ".insn r " opcode ", " func3 ", " func7 ", " rd ", " rs1 ", " rs2 "\n" > > > + > > > +#else > > > + > > > +#include > > > +#include > > > + > > > +#define DEFINE_INSN_R \ > > > + __DEFINE_ASM_GPR_NUMS \ > > > +" .macro insn_r, opcode, func3, func7, rd, rs1, rs2\n" \ > > > +" .4byte ((\\opcode << " __stringify(INSN_R_OPCODE_SHIFT) ") |" \ > > > +" (\\func3 << " __stringify(INSN_R_FUNC3_SHIFT) ") |" \ > > > +" (\\func7 << " __stringify(INSN_R_FUNC7_SHIFT) ") |" \ > > > +" (.L__gpr_num_\\rd << " __stringify(INSN_R_RD_SHIFT) ") |" \ > > > +" (.L__gpr_num_\\rs1 << " __stringify(INSN_R_RS1_SHIFT) ") |" \ > > > +" (.L__gpr_num_\\rs2 << " __stringify(INSN_R_RS2_SHIFT) "))\n" \ > > > +" .endm\n" > > > + > > > +#define UNDEFINE_INSN_R \ > > > +" .purgem insn_r\n" > > > + > > > +#define INSN_R(opcode, func3, func7, rd, rs1, rs2) \ > > > + DEFINE_INSN_R \ > > > + "insn_r " opcode ", " func3 ", " func7 ", " rd ", " rs1 ", " rs2 "\n" \ > > > + UNDEFINE_INSN_R > > > + > > > +#endif > > > + > > > +#endif /* ! __ASSEMBLY__ */ > > > + > > > +#define OPCODE(v) __ASM_STR(v) > > > +#define FUNC3(v) __ASM_STR(v) > > > +#define FUNC7(v) __ASM_STR(v) > > > +#define RD(v) __ASM_STR(v) > > > +#define RS1(v) __ASM_STR(v) > > > +#define RS2(v) __ASM_STR(v) > > > > you might want some sort of prefix here > > RISCV_RS1(v) ? > > > > While trying to adapt this for the cmo stuff I ran into the issue > > of bpf complaining that "IMM" is already defined there. > > > > And names above are generic enough that these also > > might conflict with other stuff. > > I have updated the KVM RISC-V queue to use the "RV_" prefix > in macro names. that is great to hear. Thanks a lot for doing that. Heiko > > > +#define __REG(v) __ASM_STR(x ## v) > > > +#define __RD(v) __REG(v) > > > +#define __RS1(v) __REG(v) > > > +#define __RS2(v) __REG(v) > > > + > > > +#endif /* __ASM_INSN_DEF_H */ > > > > > > > > > > > >