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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DDE6AC4708C for ; Tue, 6 Dec 2022 15:20:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Cc9o5flOtAXuhB90XOUgtkq30D5C5zghSg7nON6asoc=; b=XZotNGUWg14TVk fKGMXfAvmMz77Fz7CBmkEF3O2JRFRTrJzoqPE/AW1GgilA/7YtFsnihJuz4sv83n7sgzFy0OTM4Gb maOb2JQdLFEAh0z/Q8vpDHcGs5SpAgRmvz5vHXyCaZGdtCIJdW1CAUAGlf1a2ikOiUWs66HewQm0T 3ffc297dyOajdTVZqLkg8kE7tUnOzmGfyIYLOgDoJY3XgFqBdxt99G3BwMSqQzAdG5nsGQSRoX5+2 xQbaIFp/sw78zC7e1ERcF10rg3XFmy4HokW/83pzxgDjniBnOlDOk7ZESlj+SvjWLaUKoqlf+o6tE QtYMdAlIKG+GAZfhx4fA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2Zjo-00CEP5-3t; Tue, 06 Dec 2022 15:20:04 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2ZR0-00Btjx-Fi; Tue, 06 Dec 2022 15:00:40 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3D71EB81A27; Tue, 6 Dec 2022 15:00:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54919C433D6; Tue, 6 Dec 2022 15:00:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670338834; bh=3c6kibuQcbp7UNuOk1VcKWNfFbF3s27lK25A447UzA0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=py2GCys+Mcu9ZsFJkyBdhB1WOMuHh7A7c5fjZLcYjPhIr8/Xj4MT+hh1bYk0Tu2uy NQ6vr2+qdQEZnVE8g2t1mpjtTXlsnAJ3a837AFInf5GXQVtLHROIz2cwSeitaA4IjW FWEJltqCYqGEgL/+oKANoZKRSGRHRGeKvjek3StjY8UnI++1AsszgJomVzAMyMg39b n0nB50HxU4WKpaUz79ZMA9rX7ky7SF08dVZhLEU0OQHHwJr/UtGvG/wSRfrVYNx4n7 uJkb4f61oWyoOUq274IJUGKYAul9ObboS1OqWqUIyBthcY7q4/v68ibdvr0CkO8NBV 7qflmREUz9rmA== Date: Tue, 6 Dec 2022 22:50:37 +0800 From: Jisheng Zhang To: Guo Ren Cc: Palmer Dabbelt , Paul Walmsley , Albert Ou , Anup Patel , Atish Patra , Heiko Stuebner , Andrew Jones , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org Subject: Re: [PATCH v2 09/13] riscv: switch to relative alternative entries Message-ID: References: <20221204174632.3677-1-jszhang@kernel.org> <20221204174632.3677-10-jszhang@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_070038_903210_117C0251 X-CRM114-Status: GOOD ( 31.21 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Dec 06, 2022 at 12:34:40PM +0800, Guo Ren wrote: > On Mon, Dec 5, 2022 at 11:28 PM Jisheng Zhang wrote: > > > > On Mon, Dec 05, 2022 at 08:51:41AM +0800, Guo Ren wrote: > > > On Mon, Dec 5, 2022 at 1:57 AM Jisheng Zhang wrote: > > > > > > > > Instead of using absolute addresses for both the old instrucions and > > > > the alternative instructions, use offsets relative to the alt_entry > > > > values. So we can not only cut the size of the alternative entry, but > > > > also meet the prerequisite for patching alternatives in the vDSO, > > > > since absolute alternative entries are subject to dynamic relocation, > > > > which is incompatible with the vDSO building. > > > > > > > > Signed-off-by: Jisheng Zhang > > > > --- > > > > arch/riscv/errata/sifive/errata.c | 4 +++- > > > > arch/riscv/errata/thead/errata.c | 11 ++++++++--- > > > > arch/riscv/include/asm/alternative-macros.h | 20 ++++++++++---------- > > > > arch/riscv/include/asm/alternative.h | 12 ++++++------ > > > > arch/riscv/kernel/cpufeature.c | 13 ++++++------- > > > > 5 files changed, 33 insertions(+), 27 deletions(-) > > > > > > > > diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c > > > > index 1031038423e7..0e537cdfd324 100644 > > > > --- a/arch/riscv/errata/sifive/errata.c > > > > +++ b/arch/riscv/errata/sifive/errata.c > > > > @@ -107,7 +107,9 @@ void __init_or_module sifive_errata_patch_func(struct alt_entry *begin, > > > > > > > > tmp = (1U << alt->errata_id); > > > > if (cpu_req_errata & tmp) { > > > > - patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); > > > > + patch_text_nosync((void *)&alt->old_offset + alt->old_offset, > > > > + (void *)&alt->alt_offset + alt->alt_offset, > > > (void *)&alt->alt_offset + alt->alt_offset. ??!! > > > > Hi Guo, > > > > what's the problem? I can't catch your meaning, could you please proide > > more details? > Can you explain why: > > alt->old_ptr = (void *)&alt->old_offset + alt->old_offset Hi, when constructing the alt entry, we save the offset in then entry as below: .long \oldptr - . So we can restore the old_ptr by &alt->old_offset + alt->old_offset Thanks > > | offset | <- &offset > | ... | > | value | <- ptr = &offset + offset > > I don't make sense of the above. > > > > > Thanks > > > > > > > > > + alt->alt_len); > > > > cpu_apply_errata |= tmp; > > > > } > > > > } > > > > diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c > > > > index 21546937db39..2a6e335b5a32 100644 > > > > --- a/arch/riscv/errata/thead/errata.c > > > > +++ b/arch/riscv/errata/thead/errata.c > > > > @@ -68,6 +68,7 @@ void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct al > > > > struct alt_entry *alt; > > > > u32 cpu_req_errata = thead_errata_probe(stage, archid, impid); > > > > u32 tmp; > > > > + void *oldptr, *updptr; > > > > > > > > for (alt = begin; alt < end; alt++) { > > > > if (alt->vendor_id != THEAD_VENDOR_ID) > > > > @@ -77,12 +78,16 @@ void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct al > > > > > > > > tmp = (1U << alt->errata_id); > > > > if (cpu_req_errata & tmp) { > > > > + oldptr = (void *)&alt->old_offset + alt->old_offset; > > > > + updptr = (void *)&alt->alt_offset + alt->alt_offset; > > > > + > > > > /* On vm-alternatives, the mmu isn't running yet */ > > > > if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) > > > > - memcpy((void *)__pa_symbol(alt->old_ptr), > > > > - (void *)__pa_symbol(alt->alt_ptr), alt->alt_len); > > > > + memcpy((void *)__pa_symbol(oldptr), > > > > + (void *)__pa_symbol(updptr), > > > > + alt->alt_len); > > > > else > > > > - patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); > > > > + patch_text_nosync(oldptr, updptr, alt->alt_len); > > > > } > > > > } > > > > > > > > diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h > > > > index ec2f3f1b836f..dd40727bc859 100644 > > > > --- a/arch/riscv/include/asm/alternative-macros.h > > > > +++ b/arch/riscv/include/asm/alternative-macros.h > > > > @@ -7,11 +7,11 @@ > > > > #ifdef __ASSEMBLY__ > > > > > > > > .macro ALT_ENTRY oldptr newptr vendor_id errata_id new_len > > > > - RISCV_PTR \oldptr > > > > - RISCV_PTR \newptr > > > > - REG_ASM \vendor_id > > > > - REG_ASM \new_len > > > > - .word \errata_id > > > > + .long \oldptr - . > > > > + .long \newptr - . > > > > + .short \vendor_id > > > > + .short \new_len > > > > + .long \errata_id > > > > .endm > > > > > > > > .macro ALT_NEW_CONTENT vendor_id, errata_id, enable = 1, new_c : vararg > > > > @@ -75,11 +75,11 @@ > > > > #include > > > > > > > > #define ALT_ENTRY(oldptr, newptr, vendor_id, errata_id, newlen) \ > > > > - RISCV_PTR " " oldptr "\n" \ > > > > - RISCV_PTR " " newptr "\n" \ > > > > - REG_ASM " " vendor_id "\n" \ > > > > - REG_ASM " " newlen "\n" \ > > > > - ".word " errata_id "\n" > > > > + ".long ((" oldptr ") - .) \n" \ > > > > + ".long ((" newptr ") - .) \n" \ > > > > + ".short " vendor_id "\n" \ > > > > + ".short " newlen "\n" \ > > > > + ".long " errata_id "\n" > > > > > > > > #define ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c) \ > > > > ".if " __stringify(enable) " == 1\n" \ > > > > diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h > > > > index 33eae9541684..3baf32e05b46 100644 > > > > --- a/arch/riscv/include/asm/alternative.h > > > > +++ b/arch/riscv/include/asm/alternative.h > > > > @@ -33,12 +33,12 @@ void riscv_alternative_fix_jal(void *alt_ptr, unsigned int len, > > > > int patch_offset); > > > > > > > > struct alt_entry { > > > > - void *old_ptr; /* address of original instruciton or data */ > > > > - void *alt_ptr; /* address of replacement instruction or data */ > > > > - unsigned long vendor_id; /* cpu vendor id */ > > > > - unsigned long alt_len; /* The replacement size */ > > > > - unsigned int errata_id; /* The errata id */ > > > > -} __packed; > > > > + s32 old_offset; /* offset to original instruciton or data */ > > > > + s32 alt_offset; /* offset to replacement instruction or data */ > > > > + u16 vendor_id; /* cpu vendor id */ > > > > + u16 alt_len; /* The replacement size */ > > > > + u32 errata_id; /* The errata id */ > > > > +}; > > > > > > > > struct errata_checkfunc_id { > > > > unsigned long vendor_id; > > > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > > > > index 6244be5cd94a..adeac90b1d8e 100644 > > > > --- a/arch/riscv/kernel/cpufeature.c > > > > +++ b/arch/riscv/kernel/cpufeature.c > > > > @@ -257,6 +257,7 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, > > > > unsigned int stage) > > > > { > > > > struct alt_entry *alt; > > > > + void *oldptr, *updptr; > > > > > > > > if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) > > > > return; > > > > @@ -270,17 +271,15 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, > > > > continue; > > > > } > > > > > > > > + oldptr = (void *)&alt->old_offset + alt->old_offset; > > > > + updptr = (void *)&alt->alt_offset + alt->alt_offset; > > > > if (!__riscv_isa_extension_available(NULL, alt->errata_id)) > > > > continue; > > > > > > > > /* do the basic patching */ > > > > - patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); > > > > - riscv_alternative_fix_auipc_jalr(alt->old_ptr, > > > > - alt->alt_len, > > > > - alt->old_ptr - alt->alt_ptr); > > > > - riscv_alternative_fix_jal(alt->old_ptr, > > > > - alt->alt_len, > > > > - alt->old_ptr - alt->alt_ptr); > > > > + patch_text_nosync(oldptr, updptr, alt->alt_len); > > > > + riscv_alternative_fix_auipc_jalr(oldptr, alt->alt_len, oldptr - updptr); > > > > + riscv_alternative_fix_jal(oldptr, alt->alt_len, oldptr - updptr); > > > > } > > > > } > > > > #endif > > > > -- > > > > 2.37.2 > > > > > > > > > > > > > -- > > > Best Regards > > > Guo Ren > > > > -- > Best Regards > Guo Ren _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv