mirror of
https://github.com/torvalds/linux.git
synced 2024-11-24 13:11:40 +00:00
b91540d52a
This patch adds EFI runtime service support for RISC-V. Signed-off-by: Atish Patra <atish.patra@wdc.com> [ardb: - Remove the page check] Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (C) 2020 Western Digital Corporation or its affiliates.
|
|
* Adapted from arch/arm64/kernel/efi.c
|
|
*/
|
|
|
|
#include <linux/efi.h>
|
|
#include <linux/init.h>
|
|
|
|
#include <asm/efi.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/pgtable-bits.h>
|
|
|
|
/*
|
|
* 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 = pte_val(pte) | _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);
|
|
}
|