From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- arch/riscv/kernel/efi.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 arch/riscv/kernel/efi.c (limited to 'arch/riscv/kernel/efi.c') diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c new file mode 100644 index 000000000..1aa540350 --- /dev/null +++ b/arch/riscv/kernel/efi.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 Western Digital Corporation or its affiliates. + * Adapted from arch/arm64/kernel/efi.c + */ + +#include +#include + +#include +#include +#include + +/* + * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be + * executable, everything else can be mapped with the XN bits + * set. Also take the new (optional) RO/XP bits into account. + */ +static __init pgprot_t efimem_to_pgprot_map(efi_memory_desc_t *md) +{ + u64 attr = md->attribute; + u32 type = md->type; + + if (type == EFI_MEMORY_MAPPED_IO) + return PAGE_KERNEL; + + /* R-- */ + if ((attr & (EFI_MEMORY_XP | EFI_MEMORY_RO)) == + (EFI_MEMORY_XP | EFI_MEMORY_RO)) + return PAGE_KERNEL_READ; + + /* R-X */ + if (attr & EFI_MEMORY_RO) + return PAGE_KERNEL_READ_EXEC; + + /* RW- */ + if (((attr & (EFI_MEMORY_RP | EFI_MEMORY_WP | EFI_MEMORY_XP)) == + EFI_MEMORY_XP) || + type != EFI_RUNTIME_SERVICES_CODE) + return PAGE_KERNEL; + + /* RWX */ + return PAGE_KERNEL_EXEC; +} + +int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md) +{ + pgprot_t prot = __pgprot(pgprot_val(efimem_to_pgprot_map(md)) & + ~(_PAGE_GLOBAL)); + int i; + + /* RISC-V maps one page at a time */ + for (i = 0; i < md->num_pages; i++) + create_pgd_mapping(mm->pgd, md->virt_addr + i * PAGE_SIZE, + md->phys_addr + i * PAGE_SIZE, + PAGE_SIZE, prot); + return 0; +} + +static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data) +{ + efi_memory_desc_t *md = data; + pte_t pte = READ_ONCE(*ptep); + unsigned long val; + + if (md->attribute & EFI_MEMORY_RO) { + val = pte_val(pte) & ~_PAGE_WRITE; + val |= _PAGE_READ; + pte = __pte(val); + } + if (md->attribute & EFI_MEMORY_XP) { + val = pte_val(pte) & ~_PAGE_EXEC; + pte = __pte(val); + } + set_pte(ptep, pte); + + return 0; +} + +int __init efi_set_mapping_permissions(struct mm_struct *mm, + efi_memory_desc_t *md) +{ + BUG_ON(md->type != EFI_RUNTIME_SERVICES_CODE && + md->type != EFI_RUNTIME_SERVICES_DATA); + + /* + * Calling apply_to_page_range() is only safe on regions that are + * guaranteed to be mapped down to pages. Since we are only called + * for regions that have been mapped using efi_create_mapping() above + * (and this is checked by the generic Memory Attributes table parsing + * routines), there is no need to check that again here. + */ + return apply_to_page_range(mm, md->virt_addr, + md->num_pages << EFI_PAGE_SHIFT, + set_permissions, md); +} -- cgit v1.2.3