From patchwork Tue Mar 14 14:21:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13174513 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 0DF90C7618B for ; Tue, 14 Mar 2023 14:22:35 +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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aM+mupmW1+r7nuSQcSj29ZGa7Xd/+zDkLQZ2q4c7fpg=; b=mayQF6k3HiCqBc fus2e5QC4X2yXK6w5aDjt0EMs6Qoh5RmLbUzqMCeBrvZh7AzzuYkwrO/QvlCKYlNSfqmXA0x9XG89 FD48ovPJUG9WZy1ZLYTYBcbUM+C2JA3+RBO/0PA76029zRS7nkEsUrK0SRccgLkBYg7ptg2VcUVcj H8ov+Pdlt79qxnbwMZLfnoypzgr4uXPwjLdY2upPUZdmzMibC2R+fPDffyNE8MVOXXlmz8UhGG4wz ZmyJMFvuPLAZOyDJR7svOyz6m3IgD6Kdtt9+8Z5vZGmbnEHqSartc8glZblHOTB9KWdUHJdcwhkeq FxpZe9aDnRnzyjv98/wg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pc5X7-00ARiS-19; Tue, 14 Mar 2023 14:21:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pc5Wy-00ARf4-1R for linux-arm-kernel@lists.infradead.org; Tue, 14 Mar 2023 14:21:40 +0000 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 4B0E31042; Tue, 14 Mar 2023 07:22:18 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 7C42A3F67D; Tue, 14 Mar 2023 07:21:33 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: anshuman.khandual@arm.com, ardb@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, ryan.roberts@arm.com, will@kernel.org Subject: [PATCH 1/2] arm64: mm: move fixmap code to its own file Date: Tue, 14 Mar 2023 14:21:24 +0000 Message-Id: <20230314142125.502043-2-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230314142125.502043-1-mark.rutland@arm.com> References: <20230314142125.502043-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230314_072136_577215_F3897A17 X-CRM114-Status: GOOD ( 32.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Over time, arm64's mm/mmu.c has become increasingly large and painful to navigate. Move the fixmap code to its own file where it can be understood in isolation. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Ryan Roberts Cc: Will Deacon --- arch/arm64/include/asm/fixmap.h | 1 + arch/arm64/include/asm/mmu.h | 2 + arch/arm64/mm/Makefile | 2 +- arch/arm64/mm/fixmap.c | 215 ++++++++++++++++++++++++++++++++ arch/arm64/mm/mmu.c | 197 +---------------------------- 5 files changed, 222 insertions(+), 195 deletions(-) create mode 100644 arch/arm64/mm/fixmap.c diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h index 71ed5fdf718b..c153f069e9c9 100644 --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -101,6 +101,7 @@ enum fixed_addresses { #define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE) void __init early_fixmap_init(void); +void __init fixmap_copy(pgd_t *pgdir); #define __early_set_fixmap __set_fixmap diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 48f8466a4be9..4384eaa0aeb7 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -65,6 +65,8 @@ extern void paging_init(void); extern void bootmem_init(void); extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt); extern void init_mem_pgprot(void); +extern void create_mapping_noalloc(phys_addr_t phys, unsigned long virt, + phys_addr_t size, pgprot_t prot); extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, unsigned long virt, phys_addr_t size, pgprot_t prot, bool page_mappings_only); diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index ff1e800ba7a1..dbd1bc95967d 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -2,7 +2,7 @@ obj-y := dma-mapping.o extable.o fault.o init.o \ cache.o copypage.o flush.o \ ioremap.o mmap.o pgd.o mmu.o \ - context.o proc.o pageattr.o + context.o proc.o pageattr.o fixmap.o obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_PTDUMP_CORE) += ptdump.o obj-$(CONFIG_PTDUMP_DEBUGFS) += ptdump_debugfs.o diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c new file mode 100644 index 000000000000..54e50552bfe3 --- /dev/null +++ b/arch/arm64/mm/fixmap.c @@ -0,0 +1,215 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Fixmap manipulation code + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; +static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; +static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; + +static inline pud_t *fixmap_pud(unsigned long addr) +{ + pgd_t *pgdp = pgd_offset_k(addr); + p4d_t *p4dp = p4d_offset(pgdp, addr); + p4d_t p4d = READ_ONCE(*p4dp); + + BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); + + return pud_offset_kimg(p4dp, addr); +} + +static inline pmd_t *fixmap_pmd(unsigned long addr) +{ + pud_t *pudp = fixmap_pud(addr); + pud_t pud = READ_ONCE(*pudp); + + BUG_ON(pud_none(pud) || pud_bad(pud)); + + return pmd_offset_kimg(pudp, addr); +} + +static inline pte_t *fixmap_pte(unsigned long addr) +{ + return &bm_pte[pte_index(addr)]; +} + +/* + * The p*d_populate functions call virt_to_phys implicitly so they can't be used + * directly on kernel symbols (bm_p*d). This function is called too early to use + * lm_alias so __p*d_populate functions must be used to populate with the + * physical address from __pa_symbol. + */ +void __init early_fixmap_init(void) +{ + pgd_t *pgdp; + p4d_t *p4dp, p4d; + pud_t *pudp; + pmd_t *pmdp; + unsigned long addr = FIXADDR_START; + + pgdp = pgd_offset_k(addr); + p4dp = p4d_offset(pgdp, addr); + p4d = READ_ONCE(*p4dp); + if (CONFIG_PGTABLE_LEVELS > 3 && + !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { + /* + * We only end up here if the kernel mapping and the fixmap + * share the top level pgd entry, which should only happen on + * 16k/4 levels configurations. + */ + BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); + pudp = pud_offset_kimg(p4dp, addr); + } else { + if (p4d_none(p4d)) + __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); + pudp = fixmap_pud(addr); + } + if (pud_none(READ_ONCE(*pudp))) + __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); + pmdp = fixmap_pmd(addr); + __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); + + /* + * The boot-ioremap range spans multiple pmds, for which + * we are not prepared: + */ + BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) + != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); + + if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) + || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { + WARN_ON(1); + pr_warn("pmdp %p != %p, %p\n", + pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), + fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); + pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", + fix_to_virt(FIX_BTMAP_BEGIN)); + pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", + fix_to_virt(FIX_BTMAP_END)); + + pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); + pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); + } +} + +/* + * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we + * ever need to use IPIs for TLB broadcasting, then we're in trouble here. + */ +void __set_fixmap(enum fixed_addresses idx, + phys_addr_t phys, pgprot_t flags) +{ + unsigned long addr = __fix_to_virt(idx); + pte_t *ptep; + + BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); + + ptep = fixmap_pte(addr); + + if (pgprot_val(flags)) { + set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); + } else { + pte_clear(&init_mm, addr, ptep); + flush_tlb_kernel_range(addr, addr+PAGE_SIZE); + } +} + +void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) +{ + const u64 dt_virt_base = __fix_to_virt(FIX_FDT); + int offset; + void *dt_virt; + + /* + * Check whether the physical FDT address is set and meets the minimum + * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be + * at least 8 bytes so that we can always access the magic and size + * fields of the FDT header after mapping the first chunk, double check + * here if that is indeed the case. + */ + BUILD_BUG_ON(MIN_FDT_ALIGN < 8); + if (!dt_phys || dt_phys % MIN_FDT_ALIGN) + return NULL; + + /* + * Make sure that the FDT region can be mapped without the need to + * allocate additional translation table pages, so that it is safe + * to call create_mapping_noalloc() this early. + * + * On 64k pages, the FDT will be mapped using PTEs, so we need to + * be in the same PMD as the rest of the fixmap. + * On 4k pages, we'll use section mappings for the FDT so we only + * have to be in the same PUD. + */ + BUILD_BUG_ON(dt_virt_base % SZ_2M); + + BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != + __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); + + offset = dt_phys % SWAPPER_BLOCK_SIZE; + dt_virt = (void *)dt_virt_base + offset; + + /* map the first chunk so we can read the size from the header */ + create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), + dt_virt_base, SWAPPER_BLOCK_SIZE, prot); + + if (fdt_magic(dt_virt) != FDT_MAGIC) + return NULL; + + *size = fdt_totalsize(dt_virt); + if (*size > MAX_FDT_SIZE) + return NULL; + + if (offset + *size > SWAPPER_BLOCK_SIZE) + create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, + round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); + + return dt_virt; +} + +/* + * Copy the fixmap region into a new pgdir. + */ +void __init fixmap_copy(pgd_t *pgdir) +{ + if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdir, FIXADDR_START)))) { + /* + * The fixmap falls in a separate pgd to the kernel, and doesn't + * live in the carveout for the swapper_pg_dir. We can simply + * re-use the existing dir for the fixmap. + */ + set_pgd(pgd_offset_pgd(pgdir, FIXADDR_START), + READ_ONCE(*pgd_offset_k(FIXADDR_START))); + } else if (CONFIG_PGTABLE_LEVELS > 3) { + pgd_t *bm_pgdp; + p4d_t *bm_p4dp; + pud_t *bm_pudp; + /* + * The fixmap shares its top level pgd entry with the kernel + * mapping. This can really only occur when we are running + * with 16k/4 levels, so we can simply reuse the pud level + * entry instead. + */ + BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); + bm_pgdp = pgd_offset_pgd(pgdir, FIXADDR_START); + bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); + bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); + pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); + pud_clear_fixmap(); + } else { + BUG(); + } +} diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 6f9d8898a025..f67bd80135c3 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -71,10 +71,6 @@ long __section(".mmuoff.data.write") __early_cpu_boot_status; unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; EXPORT_SYMBOL(empty_zero_page); -static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; -static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; -static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; - static DEFINE_SPINLOCK(swapper_pgdir_lock); static DEFINE_MUTEX(fixmap_lock); @@ -450,8 +446,8 @@ static phys_addr_t pgd_pgtable_alloc(int shift) * without allocating new levels of table. Note that this permits the * creation of new section or page entries. */ -static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, - phys_addr_t size, pgprot_t prot) +void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, + phys_addr_t size, pgprot_t prot) { if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", @@ -734,34 +730,7 @@ static void __init map_kernel(pgd_t *pgdp) &vmlinux_initdata, 0, VM_NO_GUARD); map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); - if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { - /* - * The fixmap falls in a separate pgd to the kernel, and doesn't - * live in the carveout for the swapper_pg_dir. We can simply - * re-use the existing dir for the fixmap. - */ - set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), - READ_ONCE(*pgd_offset_k(FIXADDR_START))); - } else if (CONFIG_PGTABLE_LEVELS > 3) { - pgd_t *bm_pgdp; - p4d_t *bm_p4dp; - pud_t *bm_pudp; - /* - * The fixmap shares its top level pgd entry with the kernel - * mapping. This can really only occur when we are running - * with 16k/4 levels, so we can simply reuse the pud level - * entry instead. - */ - BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); - bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); - bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); - bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); - pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); - pud_clear_fixmap(); - } else { - BUG(); - } - + fixmap_copy(pgdp); kasan_copy_shadow(pgdp); } @@ -1176,166 +1145,6 @@ void vmemmap_free(unsigned long start, unsigned long end, } #endif /* CONFIG_MEMORY_HOTPLUG */ -static inline pud_t *fixmap_pud(unsigned long addr) -{ - pgd_t *pgdp = pgd_offset_k(addr); - p4d_t *p4dp = p4d_offset(pgdp, addr); - p4d_t p4d = READ_ONCE(*p4dp); - - BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); - - return pud_offset_kimg(p4dp, addr); -} - -static inline pmd_t *fixmap_pmd(unsigned long addr) -{ - pud_t *pudp = fixmap_pud(addr); - pud_t pud = READ_ONCE(*pudp); - - BUG_ON(pud_none(pud) || pud_bad(pud)); - - return pmd_offset_kimg(pudp, addr); -} - -static inline pte_t *fixmap_pte(unsigned long addr) -{ - return &bm_pte[pte_index(addr)]; -} - -/* - * The p*d_populate functions call virt_to_phys implicitly so they can't be used - * directly on kernel symbols (bm_p*d). This function is called too early to use - * lm_alias so __p*d_populate functions must be used to populate with the - * physical address from __pa_symbol. - */ -void __init early_fixmap_init(void) -{ - pgd_t *pgdp; - p4d_t *p4dp, p4d; - pud_t *pudp; - pmd_t *pmdp; - unsigned long addr = FIXADDR_START; - - pgdp = pgd_offset_k(addr); - p4dp = p4d_offset(pgdp, addr); - p4d = READ_ONCE(*p4dp); - if (CONFIG_PGTABLE_LEVELS > 3 && - !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { - /* - * We only end up here if the kernel mapping and the fixmap - * share the top level pgd entry, which should only happen on - * 16k/4 levels configurations. - */ - BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); - pudp = pud_offset_kimg(p4dp, addr); - } else { - if (p4d_none(p4d)) - __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); - pudp = fixmap_pud(addr); - } - if (pud_none(READ_ONCE(*pudp))) - __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); - pmdp = fixmap_pmd(addr); - __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); - - /* - * The boot-ioremap range spans multiple pmds, for which - * we are not prepared: - */ - BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) - != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); - - if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) - || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { - WARN_ON(1); - pr_warn("pmdp %p != %p, %p\n", - pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), - fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); - pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", - fix_to_virt(FIX_BTMAP_BEGIN)); - pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", - fix_to_virt(FIX_BTMAP_END)); - - pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); - pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); - } -} - -/* - * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we - * ever need to use IPIs for TLB broadcasting, then we're in trouble here. - */ -void __set_fixmap(enum fixed_addresses idx, - phys_addr_t phys, pgprot_t flags) -{ - unsigned long addr = __fix_to_virt(idx); - pte_t *ptep; - - BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); - - ptep = fixmap_pte(addr); - - if (pgprot_val(flags)) { - set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); - } else { - pte_clear(&init_mm, addr, ptep); - flush_tlb_kernel_range(addr, addr+PAGE_SIZE); - } -} - -void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) -{ - const u64 dt_virt_base = __fix_to_virt(FIX_FDT); - int offset; - void *dt_virt; - - /* - * Check whether the physical FDT address is set and meets the minimum - * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be - * at least 8 bytes so that we can always access the magic and size - * fields of the FDT header after mapping the first chunk, double check - * here if that is indeed the case. - */ - BUILD_BUG_ON(MIN_FDT_ALIGN < 8); - if (!dt_phys || dt_phys % MIN_FDT_ALIGN) - return NULL; - - /* - * Make sure that the FDT region can be mapped without the need to - * allocate additional translation table pages, so that it is safe - * to call create_mapping_noalloc() this early. - * - * On 64k pages, the FDT will be mapped using PTEs, so we need to - * be in the same PMD as the rest of the fixmap. - * On 4k pages, we'll use section mappings for the FDT so we only - * have to be in the same PUD. - */ - BUILD_BUG_ON(dt_virt_base % SZ_2M); - - BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != - __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); - - offset = dt_phys % SWAPPER_BLOCK_SIZE; - dt_virt = (void *)dt_virt_base + offset; - - /* map the first chunk so we can read the size from the header */ - create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), - dt_virt_base, SWAPPER_BLOCK_SIZE, prot); - - if (fdt_magic(dt_virt) != FDT_MAGIC) - return NULL; - - *size = fdt_totalsize(dt_virt); - if (*size > MAX_FDT_SIZE) - return NULL; - - if (offset + *size > SWAPPER_BLOCK_SIZE) - create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, - round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); - - return dt_virt; -} - int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) { pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); From patchwork Tue Mar 14 14:21:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13174512 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 8AF95C7618D for ; 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Tue, 14 Mar 2023 14:21:44 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pc5Wz-00ARfi-21 for linux-arm-kernel@lists.infradead.org; Tue, 14 Mar 2023 14:21:40 +0000 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 3EB15150C; Tue, 14 Mar 2023 07:22:20 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 93B8C3F67D; Tue, 14 Mar 2023 07:21:35 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: anshuman.khandual@arm.com, ardb@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, ryan.roberts@arm.com, will@kernel.org Subject: [PATCH 2/2] arm64: mm: always map fixmap at page granularity Date: Tue, 14 Mar 2023 14:21:25 +0000 Message-Id: <20230314142125.502043-3-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230314142125.502043-1-mark.rutland@arm.com> References: <20230314142125.502043-1-mark.rutland@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230314_072137_765181_C938E69E X-CRM114-Status: GOOD ( 31.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Today the fixmap code largely maps elements at PAGE_SIZE granularity, but we special-case the FDT mapping such that it can be mapped with 2M block mappings when 4K pages are in use. The original rationale for this was simplicity, but it has some unfortunate side-effects, and complicates portions of the fixmap code (i.e. is not so simple after all). The FDT can be up to 2M in size but is only required to have 8-byte alignment, and so it may straddle a 2M boundary. Thus when using 2M block mappings we may map up to 4M of memory surrounding the FDT. This is unfortunate as most of that memory will be unrelated to the FDT, and any pages which happen to share a 2M block with the FDT will by mapped with Normal Write-Back Cacheable attributes, which might not be what we want elsewhere (e.g. for carve-outs using Non-Cacheable attributes). The logic to handle mapping the FDT with 2M blocks requires some special cases in the fixmap code, and ties it to the early page table configuration by virtue of the SWAPPER_TABLE_SHIFT and SWAPPER_BLOCK_SIZE constants used to determine the granularity used to map the FDT. This patch simplifies the FDT logic and removes the unnecessary mappings of surrounding pages by always mapping the FDT at page granularity as with all other fixmap mappings. To do so we statically reserve multiple PTE tables to cover the fixmap VA range. Since the FDT can be at most 2M, for 4K pages we only need to allocate a single additional PTE table, and for 16K and 64K pages the existing single PTE table is sufficient. The PTE table allocation scales with the number of slots reserved in the fixmap, and so this also makes it easier to add more fixmap entries if we require those in future. Our VA layout means that the fixmap will always fall within a single PMD table (and consequently, within a single PUD/P4D/PGD entry), which we can verify at compile time with a static_assert(). With that assert a number of runtime warnings become impossible, and are removed. I've boot-tested this patch with both 4K and 64K pages. Signed-off-by: Mark Rutland Cc: Anshuman Khandual Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Ryan Roberts Cc: Will Deacon --- arch/arm64/include/asm/fixmap.h | 14 +-- arch/arm64/include/asm/kernel-pgtable.h | 5 +- arch/arm64/mm/fixmap.c | 148 +++++++++++------------- 3 files changed, 77 insertions(+), 90 deletions(-) diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h index c153f069e9c9..c59d433c1801 100644 --- a/arch/arm64/include/asm/fixmap.h +++ b/arch/arm64/include/asm/fixmap.h @@ -36,17 +36,13 @@ enum fixed_addresses { FIX_HOLE, /* - * Reserve a virtual window for the FDT that is 2 MB larger than the - * maximum supported size, and put it at the top of the fixmap region. - * The additional space ensures that any FDT that does not exceed - * MAX_FDT_SIZE can be mapped regardless of whether it crosses any - * 2 MB alignment boundaries. - * - * Keep this at the top so it remains 2 MB aligned. + * Reserve a virtual window for the FDT that is a page bigger than the + * maximum supported size. The additional space ensures that any FDT + * that does not exceed MAX_FDT_SIZE can be mapped regardless of + * whether it crosses any page boundary. */ -#define FIX_FDT_SIZE (MAX_FDT_SIZE + SZ_2M) FIX_FDT_END, - FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1, + FIX_FDT = FIX_FDT_END + MAX_FDT_SIZE / PAGE_SIZE - 1, FIX_EARLYCON_MEM_BASE, FIX_TEXT_POKE0, diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index fcd14197756f..186dd7f85b14 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -59,8 +59,11 @@ #define EARLY_KASLR (0) #endif +#define SPAN_NR_ENTRIES(vstart, vend, shift) \ + ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1) + #define EARLY_ENTRIES(vstart, vend, shift, add) \ - ((((vend) - 1) >> (shift)) - ((vstart) >> (shift)) + 1 + add) + (SPAN_NR_ENTRIES(vstart, vend, shift) + (add)) #define EARLY_PGDS(vstart, vend, add) (EARLY_ENTRIES(vstart, vend, PGDIR_SHIFT, add)) diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c index 54e50552bfe3..d7a6a485f361 100644 --- a/arch/arm64/mm/fixmap.c +++ b/arch/arm64/mm/fixmap.c @@ -16,34 +16,77 @@ #include #include -static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; +#define NR_BM_PTE_TABLES \ + SPAN_NR_ENTRIES(FIXADDR_START, FIXADDR_TOP, PMD_SHIFT) +#define NR_BM_PMD_TABLES \ + SPAN_NR_ENTRIES(FIXADDR_START, FIXADDR_TOP, PUD_SHIFT) + +static_assert(NR_BM_PMD_TABLES == 1); + +#define __BM_TABLE_IDX(addr, shift) \ + (((addr) >> (shift)) - (FIXADDR_START >> (shift))) + +#define BM_PTE_TABLE_IDX(addr) __BM_TABLE_IDX(addr, PMD_SHIFT) + +static pte_t bm_pte[NR_BM_PTE_TABLES][PTRS_PER_PTE] __page_aligned_bss; static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; -static inline pud_t *fixmap_pud(unsigned long addr) +static inline pte_t *fixmap_pte(unsigned long addr) { - pgd_t *pgdp = pgd_offset_k(addr); - p4d_t *p4dp = p4d_offset(pgdp, addr); - p4d_t p4d = READ_ONCE(*p4dp); + return &bm_pte[BM_PTE_TABLE_IDX(addr)][pte_index(addr)]; +} - BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); +void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr) +{ + pmd_t pmd = READ_ONCE(*pmdp); + pte_t *ptep; - return pud_offset_kimg(p4dp, addr); + if (pmd_none(pmd)) { + ptep = bm_pte[BM_PTE_TABLE_IDX(addr)];; + __pmd_populate(pmdp, __pa_symbol(ptep), PMD_TYPE_TABLE); + } } -static inline pmd_t *fixmap_pmd(unsigned long addr) +void __init early_fixmap_init_pmd(pud_t *pudp, unsigned long addr, + unsigned long end) { - pud_t *pudp = fixmap_pud(addr); + unsigned long next; pud_t pud = READ_ONCE(*pudp); + pmd_t *pmdp; - BUG_ON(pud_none(pud) || pud_bad(pud)); + if (pud_none(pud)) + __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); - return pmd_offset_kimg(pudp, addr); + pmdp = pmd_offset_kimg(pudp, addr); + do { + next = pmd_addr_end(addr, end); + early_fixmap_init_pte(pmdp, addr); + } while (pmdp++, addr = next, addr != end); } -static inline pte_t *fixmap_pte(unsigned long addr) + +void __init early_fixmap_init_pud(p4d_t *p4dp, unsigned long addr, + unsigned long end) { - return &bm_pte[pte_index(addr)]; + p4d_t p4d = READ_ONCE(*p4dp); + pud_t *pudp; + + if (CONFIG_PGTABLE_LEVELS > 3 && !p4d_none(p4d) && + p4d_page_paddr(p4d) != __pa_symbol(bm_pud)) { + /* + * We only end up here if the kernel mapping and the fixmap + * share the top level pgd entry, which should only happen on + * 16k/4 levels configurations. + */ + BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); + } + + if (p4d_none(p4d)) + __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); + + pudp = pud_offset_kimg(p4dp, addr); + early_fixmap_init_pmd(pudp, addr, end); } /* @@ -54,55 +97,13 @@ static inline pte_t *fixmap_pte(unsigned long addr) */ void __init early_fixmap_init(void) { - pgd_t *pgdp; - p4d_t *p4dp, p4d; - pud_t *pudp; - pmd_t *pmdp; unsigned long addr = FIXADDR_START; + unsigned long end = FIXADDR_TOP; - pgdp = pgd_offset_k(addr); - p4dp = p4d_offset(pgdp, addr); - p4d = READ_ONCE(*p4dp); - if (CONFIG_PGTABLE_LEVELS > 3 && - !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { - /* - * We only end up here if the kernel mapping and the fixmap - * share the top level pgd entry, which should only happen on - * 16k/4 levels configurations. - */ - BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); - pudp = pud_offset_kimg(p4dp, addr); - } else { - if (p4d_none(p4d)) - __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); - pudp = fixmap_pud(addr); - } - if (pud_none(READ_ONCE(*pudp))) - __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); - pmdp = fixmap_pmd(addr); - __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); + pgd_t *pgdp = pgd_offset_k(addr); + p4d_t *p4dp = p4d_offset(pgdp, addr); - /* - * The boot-ioremap range spans multiple pmds, for which - * we are not prepared: - */ - BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) - != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); - - if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) - || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { - WARN_ON(1); - pr_warn("pmdp %p != %p, %p\n", - pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), - fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); - pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", - fix_to_virt(FIX_BTMAP_BEGIN)); - pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", - fix_to_virt(FIX_BTMAP_END)); - - pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); - pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); - } + early_fixmap_init_pud(p4dp, addr, end); } /* @@ -130,6 +131,7 @@ void __set_fixmap(enum fixed_addresses idx, void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) { const u64 dt_virt_base = __fix_to_virt(FIX_FDT); + phys_addr_t dt_phys_base; int offset; void *dt_virt; @@ -144,27 +146,12 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) if (!dt_phys || dt_phys % MIN_FDT_ALIGN) return NULL; - /* - * Make sure that the FDT region can be mapped without the need to - * allocate additional translation table pages, so that it is safe - * to call create_mapping_noalloc() this early. - * - * On 64k pages, the FDT will be mapped using PTEs, so we need to - * be in the same PMD as the rest of the fixmap. - * On 4k pages, we'll use section mappings for the FDT so we only - * have to be in the same PUD. - */ - BUILD_BUG_ON(dt_virt_base % SZ_2M); - - BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != - __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); - - offset = dt_phys % SWAPPER_BLOCK_SIZE; + dt_phys_base = round_down(dt_phys, PAGE_SIZE); + offset = dt_phys % PAGE_SIZE; dt_virt = (void *)dt_virt_base + offset; /* map the first chunk so we can read the size from the header */ - create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), - dt_virt_base, SWAPPER_BLOCK_SIZE, prot); + create_mapping_noalloc(dt_phys_base, dt_virt_base, PAGE_SIZE, prot); if (fdt_magic(dt_virt) != FDT_MAGIC) return NULL; @@ -173,9 +160,10 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) if (*size > MAX_FDT_SIZE) return NULL; - if (offset + *size > SWAPPER_BLOCK_SIZE) - create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, - round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); + if (offset + *size > PAGE_SIZE) { + create_mapping_noalloc(dt_phys_base, dt_virt_base, + offset + *size, prot); + } return dt_virt; }