From patchwork Tue Aug 1 14:30:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksii Kurochko X-Patchwork-Id: 13336806 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 E96C8C001E0 for ; Tue, 1 Aug 2023 14:31:21 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.574251.899531 (Exim 4.92) (envelope-from ) id 1qQqOu-0007ju-5k; Tue, 01 Aug 2023 14:31:04 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 574251.899531; Tue, 01 Aug 2023 14:31:04 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qQqOu-0007jn-2r; Tue, 01 Aug 2023 14:31:04 +0000 Received: by outflank-mailman (input) for mailman id 574251; Tue, 01 Aug 2023 14:31:03 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qQqOt-0007Uu-3I for xen-devel@lists.xenproject.org; Tue, 01 Aug 2023 14:31:03 +0000 Received: from mail-lf1-x129.google.com (mail-lf1-x129.google.com [2a00:1450:4864:20::129]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 09c80964-3078-11ee-8613-37d641c3527e; Tue, 01 Aug 2023 16:31:01 +0200 (CEST) Received: by mail-lf1-x129.google.com with SMTP id 2adb3069b0e04-4fe383c1a26so3449395e87.1 for ; Tue, 01 Aug 2023 07:31:01 -0700 (PDT) Received: from fedora.. ([94.75.70.14]) by smtp.gmail.com with ESMTPSA id q28-20020ac24a7c000000b004fbac025223sm2568051lfp.22.2023.08.01.07.30.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 07:30:59 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 09c80964-3078-11ee-8613-37d641c3527e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690900261; x=1691505061; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=LUja0JE13agYREw0RGgZhxeHvXKg+830hNOPqDqfhTY=; b=lge5p9xcmTfGaaGQ9e+A3K37zgrGb+t6wHM2SMcJH9QbU4IA5XlRRCfPTnAIsvW4mF JgpW7dHuhDQxD2c/cIDllrqrAhUl7w7vQ53pNxm6Ljjnd8LivKvPyVpQGEgKzuhydLb6 7oPX3ubeKxz0paEonowdWqHxFImRnmWOOzbev1ltDVEUNiYbreclfHvj5WmtNePeRFcK tmb8DVWDkNei1woNbJdydIIbbIgfP5xiN90IPlBS/XeXyL5KoivLQpg5Lm4j0H0xUb+J LaqSxQExSFgnJ+RQtk2GMwLIXOL4P0x8iA/s6WV6t3Vr/KXfFl0qkTrCqojNY3yqW/9j f3iQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690900261; x=1691505061; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LUja0JE13agYREw0RGgZhxeHvXKg+830hNOPqDqfhTY=; b=ceyuystbpNTg2pfJ0dSvZbDJrGGpOiUJ4+iIm9B/KusRZ4QrD/jGKaYvAfJ1G6ANxB bghtMJABDD8Lp6OcJu5R0cEXFGBQszUZaSoUJ71bAZIbJxCup28fQotZSD0DUlvnv2KL jb6HLeSLfQOtJtU/HwPbM+uNpt87YYopW8EkZXo5SQ11y81sfafSKD+HSSNoZo/MX6Xk tw28IQyoWVSOzavXqW+ZfcnQ0uVRGVLz7oZxP4RcHATIdLf2mEoh+npT9fTqq/tcWYJp 3AYsTUVeX7/VzVY54QDhMAixPJR9YnocuVkBNMpuKbHcOPtH8RQvNKiuarTpe0S/fp5+ OE6w== X-Gm-Message-State: ABy/qLajBrM3wweIXnQi0k1a2HkXai/cP3qItrWf/9MRCY2UpAFK4S57 yX1yNV0aoiAQq95E3Hi7z7rnZQpaGxY= X-Google-Smtp-Source: APBJJlEENUeOEhAG0XHIXrMsupEp7O2idyzLkgPM2oOVWGd5xuYU/qcvAPm1rLiXLiQqEmRk7lFLdQ== X-Received: by 2002:ac2:4d19:0:b0:4f8:6625:f2ca with SMTP id r25-20020ac24d19000000b004f86625f2camr2382262lfi.61.1690900260555; Tue, 01 Aug 2023 07:31:00 -0700 (PDT) From: Oleksii Kurochko To: xen-devel@lists.xenproject.org Cc: Jan Beulich , Andrew Cooper , Oleksii Kurochko , Bob Eshleman , Alistair Francis , Connor Davis Subject: [PATCH v6 1/2] xen/riscv: introduce function for physical offset calculation Date: Tue, 1 Aug 2023 17:30:49 +0300 Message-ID: <1efa59f7296bd7b36f6c118b71180d86e89c72b1.1690899325.git.oleksii.kurochko@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 The function was introduced to calculate and save physical offset before MMU is enabled because access to start() is PC-relative and in case of linker_addr != load_addr it will result in incorrect value in phys_offset. Signed-off-by: Oleksii Kurochko --- Changes in V6: - After 9380f06fe8("xen: Drop the (almost) unused extern start[]") an update of calc_phys_offset() was needed: - change start to _start. - add local volatile variable load_start to get properly Xens' load address. Otherwise compile thinks that (start - XEN_VIRT_START) is equal to 0. --- Changes in V5: - update prototype of calc_phys_offset(). now it returns phys_offset. - declare phys_offset as static. - save returned value of calc_phys_offset to register s2. --- Changes in V4: - update the comment messages in head.S related to save/restore of a0/a1 regs. --- Changes in V3: - save/restore of a0/a1 registers before C first function call. --- Changes in V2: - add __ro_after_init for phys_offset variable. - remove double blank lines. - add __init for calc_phys_offset(). - update the commit message. - declaring variable phys_off as non static as it will be used in head.S. --- xen/arch/riscv/include/asm/mm.h | 2 ++ xen/arch/riscv/mm.c | 21 ++++++++++++++++++--- xen/arch/riscv/riscv64/head.S | 14 ++++++++++++++ 3 files changed, 34 insertions(+), 3 deletions(-) diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h index 5e3ac5cde3..7b94cbadd7 100644 --- a/xen/arch/riscv/include/asm/mm.h +++ b/xen/arch/riscv/include/asm/mm.h @@ -15,4 +15,6 @@ void setup_initial_pagetables(void); void enable_mmu(void); void cont_after_mmu_is_enabled(void); +unsigned long calc_phys_offset(void); + #endif /* _ASM_RISCV_MM_H */ diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c index 99ed5e9623..a73f135a3c 100644 --- a/xen/arch/riscv/mm.c +++ b/xen/arch/riscv/mm.c @@ -1,5 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0-only */ +#include #include #include #include @@ -19,9 +20,10 @@ struct mmu_desc { pte_t *pgtbl_base; }; -#define PHYS_OFFSET ((unsigned long)_start - XEN_VIRT_START) -#define LOAD_TO_LINK(addr) ((addr) - PHYS_OFFSET) -#define LINK_TO_LOAD(addr) ((addr) + PHYS_OFFSET) +static unsigned long __ro_after_init phys_offset; + +#define LOAD_TO_LINK(addr) ((unsigned long)(addr) - phys_offset) +#define LINK_TO_LOAD(addr) ((unsigned long)(addr) + phys_offset) /* * It is expected that Xen won't be more then 2 MB. @@ -273,3 +275,16 @@ void __init noreturn noinline enable_mmu() switch_stack_and_jump((unsigned long)cpu0_boot_stack + STACK_SIZE, cont_after_mmu_is_enabled); } + +/* + * calc_phys_offset() should be used before MMU is enabled because access to + * start() is PC-relative and in case when load_addr != linker_addr phys_offset + * will have an incorrect value + */ +unsigned long __init calc_phys_offset(void) +{ + volatile unsigned long load_start = (unsigned long)_start; + + phys_offset = load_start - XEN_VIRT_START; + return phys_offset; +} diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S index 2c0304646a..ae194bb099 100644 --- a/xen/arch/riscv/riscv64/head.S +++ b/xen/arch/riscv/riscv64/head.S @@ -29,6 +29,20 @@ ENTRY(start) jal reset_stack + /* + * save hart_id ( bootcpu_id ) and dtb_base as a0 and a1 register can + * be used by C code + */ + mv s0, a0 + mv s1, a1 + + jal calc_phys_offset + mv s2, a0 + + /* restore hart_id ( bootcpu_id ) and dtb address */ + mv a0, s0 + mv a1, s1 + tail start_xen .section .text, "ax", %progbits From patchwork Tue Aug 1 14:30:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksii Kurochko X-Patchwork-Id: 13336808 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 9CD71C001E0 for ; Tue, 1 Aug 2023 14:31:25 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.574252.899542 (Exim 4.92) (envelope-from ) id 1qQqOx-000802-EF; Tue, 01 Aug 2023 14:31:07 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 574252.899542; Tue, 01 Aug 2023 14:31:07 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qQqOx-0007zv-Aq; Tue, 01 Aug 2023 14:31:07 +0000 Received: by outflank-mailman (input) for mailman id 574252; Tue, 01 Aug 2023 14:31:06 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qQqOw-0007Uu-De for xen-devel@lists.xenproject.org; Tue, 01 Aug 2023 14:31:06 +0000 Received: from mail-lf1-x130.google.com (mail-lf1-x130.google.com [2a00:1450:4864:20::130]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 0ba77181-3078-11ee-8613-37d641c3527e; Tue, 01 Aug 2023 16:31:04 +0200 (CEST) Received: by mail-lf1-x130.google.com with SMTP id 2adb3069b0e04-4fe44955decso994707e87.1 for ; Tue, 01 Aug 2023 07:31:04 -0700 (PDT) Received: from fedora.. ([94.75.70.14]) by smtp.gmail.com with ESMTPSA id q28-20020ac24a7c000000b004fbac025223sm2568051lfp.22.2023.08.01.07.31.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 07:31:01 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 0ba77181-3078-11ee-8613-37d641c3527e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690900264; x=1691505064; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=z2wBe/2TT0oHArlSRwcilGBSfEqeRZv1FMy3mGku8To=; b=AU76X6HrvfCwR7orXC8F9s4jnlr6u2luF1+/ASp8aivUV2X7rvkYzmArwUonerDH48 x03LklVGcIPHaCZ8R3J5x8NFxVCuZXpQFdu4+1z7HcT2qIorFTzgldS5TcYJt9b84BFH EDwvQAniErVgCPQO1Dmmpbc6a5DSQMrqUy/BhNUgwGRR1m5hXYvLNRKtlFwp1+djgZZO u9pOQJKcJx1ldyzW1iR6UmC9Xy1G5EAsE4KPX5p1cYchjDpR1pi4cv+32FvTdGTXtXff ZTP5mICQTU02F/obFhdZIoeNejBeePnHEizQuc043Bed8vl80tFFnoU8HfsK0cdiV6fD tMXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690900264; x=1691505064; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=z2wBe/2TT0oHArlSRwcilGBSfEqeRZv1FMy3mGku8To=; b=RhvhpYq8CnmQSIunDQ3JHk8d/oh8+yRIMxM5X+uYODLSPL1pva6/H4wfLjnRSzzW7o COIYrmCaX+08j5E6ahiORl5Mzoq5632TFsa+4J60l4LATE1ddaPRqvXgSz4C15vSlqDm yTSfg+nNcfBUlEC4bflMtvZQ9GK7qzj9jiADpjY+xa27pYDpAyvLUF6bP1vT0feXXt9w hbZqrUnZ1I2WI9x0VtUNDLslQtde2vBAbpLdqMC/uYrjy9Fs7+5Agr4EDA/+7pZ/BDiT JEKPaEOdlIiD3+Og7tcrJlRZ18jFjpZdBbQPq4fduM+/Cx+6+G8yy8902NLhS3FTdPZH 26VA== X-Gm-Message-State: ABy/qLY2d8kO0HeWAatAwEsv/g+d/K8gApmO9LovJ01j53kd7ji5Zixu 7bT84UYkZ9T9DEEO/j1lLIvC37mE2do= X-Google-Smtp-Source: APBJJlF9w5TFyHopitQl6vnQPeRhznG3phXV1OJZ1E0AsSUez1+ydMX4mmjoc6wqpyYBPFddAahfJw== X-Received: by 2002:a19:6707:0:b0:4fb:8ff3:1f74 with SMTP id b7-20020a196707000000b004fb8ff31f74mr1033067lfc.20.1690900263593; Tue, 01 Aug 2023 07:31:03 -0700 (PDT) From: Oleksii Kurochko To: xen-devel@lists.xenproject.org Cc: Jan Beulich , Andrew Cooper , Oleksii Kurochko , Bob Eshleman , Alistair Francis , Connor Davis Subject: [PATCH v6 2/2] xen/riscv: introduce identity mapping Date: Tue, 1 Aug 2023 17:30:50 +0300 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 The way how switch to virtual address was implemented in the commit e66003e7be ("xen/riscv: introduce setup_initial_pages") isn't safe enough as: * enable_mmu() depends on hooking all exceptions and pagefault. * Any exception other than pagefault, or not taking a pagefault causes it to malfunction, which means you will fail to boot depending on where Xen was loaded into memory. Instead of the proposed way of switching to virtual addresses was decided to use identity mapping for area which constains needed code to switch from identity mapping and after switching to virtual addresses, identity mapping is removed from page-tables in the following way: search for top-most page table entry and remove it. Fixes: e66003e7be ("xen/riscv: introduce setup_initial_pages") Signed-off-by: Oleksii Kurochko Suggested-by: Andrew Cooper --- Changes in V6: - t2 register was renamed to t1 as t1 isn't used anymore in turn_on_mmu(). - fold li, sll instructions to slli. - use a0 directly to calculate an argument of turn_on_mmu() instead of t0. --- Changes in V5: - update the algo of identity mapping removing. - introduce IDENT_AREA_SIZE. - introduce turn_on_mmu() function to enable and switch from 1:1 mapping. - fix typo in PGTBL_INITIAL_COUNT define. - update the comment above PGTBL_INITIAL_COUNT. - update the commit message. --- Changes in V4: - remove definition of ARRAY_SIZE and ROUNDUP as was introduced where these macros are located now. - update definition of PGTBL_INITIAL_COUNT - update the commit message - update the algo of identity mapping removing --- Changes in V3: - remove unrelated to the patch changes ( SPDX tags in config.h ). - update definition of PGTBL_INITIAL_COUNT taking into account identity mapping. - refactor remove_identity_mapping() function. - add explanatory comments in xen.lds.S and mm.c. - update commit message. - move save/restore of a0/a1 registers to [PATCH v2 2/3] xen/riscv: introduce function for physical offset calculation. --- Changes in V2: - update definition of PGTBL_INITIAL_COUNT and the comment above. - code style fixes. - 1:1 mapping for entire Xen. - remove id_addrs array becase entire Xen is mapped. - reverse condition for cycle inside remove_identity_mapping(). - fix page table walk in remove_identity_mapping(). - update the commit message. - add Suggested-by: Andrew Cooper - save hart_id and dtb_addr before call MMU related C functions. - use phys_offset variable instead of doing calcultations to get phys offset in head.S file. ( it can be easily done as entire Xen is 1:1 mapped ) - declare enable_muu() as __init. --- xen/arch/riscv/include/asm/config.h | 2 + xen/arch/riscv/include/asm/mm.h | 5 +- xen/arch/riscv/mm.c | 90 +++++++++++++++-------------- xen/arch/riscv/riscv64/head.S | 30 ++++++++++ xen/arch/riscv/setup.c | 14 +---- xen/arch/riscv/xen.lds.S | 11 ++++ 6 files changed, 97 insertions(+), 55 deletions(-) diff --git a/xen/arch/riscv/include/asm/config.h b/xen/arch/riscv/include/asm/config.h index fa90ae0898..f0544c6a20 100644 --- a/xen/arch/riscv/include/asm/config.h +++ b/xen/arch/riscv/include/asm/config.h @@ -95,6 +95,8 @@ #define RV_STAGE1_MODE SATP_MODE_SV32 #endif +#define IDENT_AREA_SIZE 64 + #endif /* __RISCV_CONFIG_H__ */ /* * Local variables: diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h index 7b94cbadd7..07c7a0abba 100644 --- a/xen/arch/riscv/include/asm/mm.h +++ b/xen/arch/riscv/include/asm/mm.h @@ -13,8 +13,11 @@ extern unsigned char cpu0_boot_stack[]; void setup_initial_pagetables(void); void enable_mmu(void); -void cont_after_mmu_is_enabled(void); + +void remove_identity_mapping(void); unsigned long calc_phys_offset(void); +void turn_on_mmu(unsigned long ra); + #endif /* _ASM_RISCV_MM_H */ diff --git a/xen/arch/riscv/mm.c b/xen/arch/riscv/mm.c index a73f135a3c..053f043a3d 100644 --- a/xen/arch/riscv/mm.c +++ b/xen/arch/riscv/mm.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include @@ -35,8 +36,11 @@ static unsigned long __ro_after_init phys_offset; * * It might be needed one more page table in case when Xen load address * isn't 2 MB aligned. + * + * CONFIG_PAGING_LEVELS page tables are needed for the identity mapping, + * except that the root page table is shared with the initial mapping */ -#define PGTBL_INITIAL_COUNT ((CONFIG_PAGING_LEVELS - 1) + 1) +#define PGTBL_INITIAL_COUNT ((CONFIG_PAGING_LEVELS - 1) * 2 + 1) pte_t __section(".bss.page_aligned") __aligned(PAGE_SIZE) stage1_pgtbl_root[PAGETABLE_ENTRIES]; @@ -75,6 +79,7 @@ static void __init setup_initial_mapping(struct mmu_desc *mmu_desc, unsigned int index; pte_t *pgtbl; unsigned long page_addr; + bool is_identity_mapping = map_start == pa_start; if ( (unsigned long)_start % XEN_PT_LEVEL_SIZE(0) ) { @@ -108,16 +113,18 @@ static void __init setup_initial_mapping(struct mmu_desc *mmu_desc, { unsigned long paddr = (page_addr - map_start) + pa_start; unsigned int permissions = PTE_LEAF_DEFAULT; + unsigned long addr = is_identity_mapping + ? page_addr : LINK_TO_LOAD(page_addr); pte_t pte_to_be_written; index = pt_index(0, page_addr); - if ( is_kernel_text(LINK_TO_LOAD(page_addr)) || - is_kernel_inittext(LINK_TO_LOAD(page_addr)) ) - permissions = - PTE_EXECUTABLE | PTE_READABLE | PTE_VALID; + if ( is_kernel_text(addr) || + is_kernel_inittext(addr) ) + permissions = + PTE_EXECUTABLE | PTE_READABLE | PTE_VALID; - if ( is_kernel_rodata(LINK_TO_LOAD(page_addr)) ) + if ( is_kernel_rodata(addr) ) permissions = PTE_READABLE | PTE_VALID; pte_to_be_written = paddr_to_pte(paddr, permissions); @@ -211,6 +218,13 @@ void __init setup_initial_pagetables(void) unsigned long linker_start = LOAD_TO_LINK(load_start); unsigned long linker_end = LOAD_TO_LINK(load_end); + unsigned long ident_start; + unsigned long ident_end; + + /* + * If the overlapping check will be removed then remove_identity_mapping() + * logic should be updated. + */ if ( (linker_start != load_start) && (linker_start <= load_end) && (load_start <= linker_end) ) { @@ -232,48 +246,40 @@ void __init setup_initial_pagetables(void) linker_start, linker_end, load_start); + + if ( linker_start == load_start ) + return; + + ident_start = (unsigned long)turn_on_mmu & XEN_PT_LEVEL_MAP_MASK(0); + ident_end = ident_start + PAGE_SIZE; + + setup_initial_mapping(&mmu_desc, + ident_start, + ident_end, + ident_start); } -void __init noreturn noinline enable_mmu() +void __init remove_identity_mapping(void) { - /* - * Calculate a linker time address of the mmu_is_enabled - * label and update CSR_STVEC with it. - * MMU is configured in a way where linker addresses are mapped - * on load addresses so in a case when linker addresses are not equal - * to load addresses, after MMU is enabled, it will cause - * an exception and jump to linker time addresses. - * Otherwise if load addresses are equal to linker addresses the code - * after mmu_is_enabled label will be executed without exception. - */ - csr_write(CSR_STVEC, LOAD_TO_LINK((unsigned long)&&mmu_is_enabled)); - - /* Ensure page table writes precede loading the SATP */ - sfence_vma(); + unsigned int i; + pte_t *pgtbl; + unsigned int index, xen_index; + unsigned long ident_start = + LINK_TO_LOAD(turn_on_mmu) & XEN_PT_LEVEL_MAP_MASK(0); - /* Enable the MMU and load the new pagetable for Xen */ - csr_write(CSR_SATP, - PFN_DOWN((unsigned long)stage1_pgtbl_root) | - RV_STAGE1_MODE << SATP_MODE_SHIFT); + for ( pgtbl = stage1_pgtbl_root, i = CONFIG_PAGING_LEVELS; i; i-- ) + { + index = pt_index(i - 1, ident_start); + xen_index = pt_index(i - 1, XEN_VIRT_START); - asm volatile ( ".p2align 2" ); - mmu_is_enabled: - /* - * Stack should be re-inited as: - * 1. Right now an address of the stack is relative to load time - * addresses what will cause an issue in case of load start address - * isn't equal to linker start address. - * 2. Addresses in stack are all load time relative which can be an - * issue in case when load start address isn't equal to linker - * start address. - * - * We can't return to the caller because the stack was reseted - * and it may have stash some variable on the stack. - * Jump to a brand new function as the stack was reseted - */ + if ( index != xen_index ) + { + pgtbl[index].pte = 0; + break; + } - switch_stack_and_jump((unsigned long)cpu0_boot_stack + STACK_SIZE, - cont_after_mmu_is_enabled); + pgtbl = (pte_t *)LOAD_TO_LINK(pte_to_paddr(pgtbl[index])); + } } /* diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S index ae194bb099..cb8888a572 100644 --- a/xen/arch/riscv/riscv64/head.S +++ b/xen/arch/riscv/riscv64/head.S @@ -39,6 +39,22 @@ ENTRY(start) jal calc_phys_offset mv s2, a0 + jal setup_initial_pagetables + + /* Calculate proper VA after jump from 1:1 mapping */ + la a0, .L_primary_switched + sub a0, a0, s2 + + jal turn_on_mmu + +.L_primary_switched: + /* + * cpu0_boot_stack address is 1:1 mapping related so it should be + * recalculated after jump from 1:1 mapping world as 1:1 mapping + * will be removed soon in start_xen(). + */ + jal reset_stack + /* restore hart_id ( bootcpu_id ) and dtb address */ mv a0, s0 mv a1, s1 @@ -54,3 +70,17 @@ ENTRY(reset_stack) ret + .section .text.ident, "ax", %progbits + +ENTRY(turn_on_mmu) + sfence.vma + + li t0, RV_STAGE1_MODE + slli t0, t0, SATP_MODE_SHIFT + + la t1, stage1_pgtbl_root + srl t1, t1, PAGE_SHIFT + or t1, t1, t0 + csrw CSR_SATP, t1 + + jr a0 diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c index dde8fb898b..6593f601c1 100644 --- a/xen/arch/riscv/setup.c +++ b/xen/arch/riscv/setup.c @@ -13,20 +13,10 @@ unsigned char __initdata cpu0_boot_stack[STACK_SIZE] void __init noreturn start_xen(unsigned long bootcpu_id, paddr_t dtb_addr) { - early_printk("Hello from C env\n"); - - setup_initial_pagetables(); - - enable_mmu(); - - for ( ;; ) - asm volatile ("wfi"); + remove_identity_mapping(); - unreachable(); -} + early_printk("Hello from C env\n"); -void __init noreturn cont_after_mmu_is_enabled(void) -{ early_printk("All set up\n"); for ( ;; ) diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S index 9064852173..3fa7db3bf9 100644 --- a/xen/arch/riscv/xen.lds.S +++ b/xen/arch/riscv/xen.lds.S @@ -31,6 +31,11 @@ SECTIONS *(.text.*) #endif + . = ALIGN(IDENT_AREA_SIZE); + _ident_start = .; + *(.text.ident) + _ident_end = .; + *(.fixup) *(.gnu.warning) . = ALIGN(POINTER_ALIGN); @@ -173,4 +178,10 @@ ASSERT(IS_ALIGNED(__bss_end, POINTER_ALIGN), "__bss_end is misaligned") ASSERT(!SIZEOF(.got), ".got non-empty") ASSERT(!SIZEOF(.got.plt), ".got.plt non-empty") +/* + * Changing the size of Xen binary can require an update of + * PGTBL_INITIAL_COUNT. + */ ASSERT(_end - _start <= MB(2), "Xen too large for early-boot assumptions") + +ASSERT(_ident_end - _ident_start <= IDENT_AREA_SIZE, "identity region is too big");