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b868fff5b1
This is a type-correctness cleanup to MMU/boot code that replaces several instances of void * and u64 with phys_addr_t (to represent addresses) and resource_size_t (to represent sizes) to emphasize that the code in question concerns physical memory specifically. The rationale for this change is to improve clarity and readability in a few modules that handle both types (physical and virtual) of address and differentiation is essential. I have left u64 in cases where the address may be either physical or virtual, where the address is exclusively virtual but used in heavy pointer arithmetic, and in cases I may have overlooked. I do not necessarily consider u64 the ideal type in those situations, but it avoids breaking existing semantics in this cleanup. This patch provably has no effect at runtime: I have verified that .text of vmlinux is identical after this change. Signed-off-by: Sam Edwards <CFSworks@gmail.com> Signed-off-by: Will Deacon <will@kernel.org>
110 lines
3.2 KiB
C
110 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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// Copyright 2023 Google LLC
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// Author: Ard Biesheuvel <ardb@google.com>
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#include <linux/types.h>
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#include <linux/sizes.h>
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#include <asm/memory.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include "pi.h"
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/**
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* map_range - Map a contiguous range of physical pages into virtual memory
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*
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* @pte: Address of physical pointer to array of pages to
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* allocate page tables from
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* @start: Virtual address of the start of the range
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* @end: Virtual address of the end of the range (exclusive)
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* @pa: Physical address of the start of the range
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* @prot: Access permissions of the range
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* @level: Translation level for the mapping
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* @tbl: The level @level page table to create the mappings in
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* @may_use_cont: Whether the use of the contiguous attribute is allowed
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* @va_offset: Offset between a physical page and its current mapping
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* in the VA space
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*/
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void __init map_range(phys_addr_t *pte, u64 start, u64 end, phys_addr_t pa,
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pgprot_t prot, int level, pte_t *tbl, bool may_use_cont,
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u64 va_offset)
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{
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u64 cmask = (level == 3) ? CONT_PTE_SIZE - 1 : U64_MAX;
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ptdesc_t protval = pgprot_val(prot) & ~PTE_TYPE_MASK;
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int lshift = (3 - level) * PTDESC_TABLE_SHIFT;
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u64 lmask = (PAGE_SIZE << lshift) - 1;
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start &= PAGE_MASK;
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pa &= PAGE_MASK;
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/* Advance tbl to the entry that covers start */
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tbl += (start >> (lshift + PAGE_SHIFT)) % PTRS_PER_PTE;
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/*
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* Set the right block/page bits for this level unless we are
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* clearing the mapping
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*/
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if (protval)
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protval |= (level == 2) ? PMD_TYPE_SECT : PTE_TYPE_PAGE;
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while (start < end) {
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u64 next = min((start | lmask) + 1, PAGE_ALIGN(end));
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if (level < 2 || (level == 2 && (start | next | pa) & lmask)) {
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/*
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* This chunk needs a finer grained mapping. Create a
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* table mapping if necessary and recurse.
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*/
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if (pte_none(*tbl)) {
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*tbl = __pte(__phys_to_pte_val(*pte) |
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PMD_TYPE_TABLE | PMD_TABLE_UXN);
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*pte += PTRS_PER_PTE * sizeof(pte_t);
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}
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map_range(pte, start, next, pa, prot, level + 1,
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(pte_t *)(__pte_to_phys(*tbl) + va_offset),
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may_use_cont, va_offset);
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} else {
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/*
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* Start a contiguous range if start and pa are
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* suitably aligned
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*/
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if (((start | pa) & cmask) == 0 && may_use_cont)
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protval |= PTE_CONT;
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/*
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* Clear the contiguous attribute if the remaining
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* range does not cover a contiguous block
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*/
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if ((end & ~cmask) <= start)
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protval &= ~PTE_CONT;
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/* Put down a block or page mapping */
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*tbl = __pte(__phys_to_pte_val(pa) | protval);
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}
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pa += next - start;
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start = next;
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tbl++;
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}
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}
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asmlinkage phys_addr_t __init create_init_idmap(pgd_t *pg_dir, ptdesc_t clrmask)
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{
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phys_addr_t ptep = (phys_addr_t)pg_dir + PAGE_SIZE; /* MMU is off */
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pgprot_t text_prot = PAGE_KERNEL_ROX;
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pgprot_t data_prot = PAGE_KERNEL;
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pgprot_val(text_prot) &= ~clrmask;
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pgprot_val(data_prot) &= ~clrmask;
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/* MMU is off; pointer casts to phys_addr_t are safe */
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map_range(&ptep, (u64)_stext, (u64)__initdata_begin,
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(phys_addr_t)_stext, text_prot, IDMAP_ROOT_LEVEL,
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(pte_t *)pg_dir, false, 0);
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map_range(&ptep, (u64)__initdata_begin, (u64)_end,
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(phys_addr_t)__initdata_begin, data_prot, IDMAP_ROOT_LEVEL,
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(pte_t *)pg_dir, false, 0);
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return ptep;
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}
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