cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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riscv-runtime.c (3184B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Extensible Firmware Interface
      4 *
      5 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
      6 *
      7 * Based on Extensible Firmware Interface Specification version 2.4
      8 * Adapted from drivers/firmware/efi/arm-runtime.c
      9 *
     10 */
     11
     12#include <linux/dmi.h>
     13#include <linux/efi.h>
     14#include <linux/io.h>
     15#include <linux/memblock.h>
     16#include <linux/mm_types.h>
     17#include <linux/preempt.h>
     18#include <linux/rbtree.h>
     19#include <linux/rwsem.h>
     20#include <linux/sched.h>
     21#include <linux/slab.h>
     22#include <linux/spinlock.h>
     23#include <linux/pgtable.h>
     24
     25#include <asm/cacheflush.h>
     26#include <asm/efi.h>
     27#include <asm/mmu.h>
     28#include <asm/pgalloc.h>
     29
     30static bool __init efi_virtmap_init(void)
     31{
     32	efi_memory_desc_t *md;
     33
     34	efi_mm.pgd = pgd_alloc(&efi_mm);
     35	mm_init_cpumask(&efi_mm);
     36	init_new_context(NULL, &efi_mm);
     37
     38	for_each_efi_memory_desc(md) {
     39		phys_addr_t phys = md->phys_addr;
     40		int ret;
     41
     42		if (!(md->attribute & EFI_MEMORY_RUNTIME))
     43			continue;
     44		if (md->virt_addr == 0)
     45			return false;
     46
     47		ret = efi_create_mapping(&efi_mm, md);
     48		if (ret) {
     49			pr_warn("  EFI remap %pa: failed to create mapping (%d)\n",
     50				&phys, ret);
     51			return false;
     52		}
     53	}
     54
     55	if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
     56		return false;
     57
     58	return true;
     59}
     60
     61/*
     62 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
     63 * non-early mapping of the UEFI system table and virtual mappings for all
     64 * EFI_MEMORY_RUNTIME regions.
     65 */
     66static int __init riscv_enable_runtime_services(void)
     67{
     68	u64 mapsize;
     69
     70	if (!efi_enabled(EFI_BOOT)) {
     71		pr_info("EFI services will not be available.\n");
     72		return 0;
     73	}
     74
     75	efi_memmap_unmap();
     76
     77	mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
     78
     79	if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
     80		pr_err("Failed to remap EFI memory map\n");
     81		return 0;
     82	}
     83
     84	if (efi_soft_reserve_enabled()) {
     85		efi_memory_desc_t *md;
     86
     87		for_each_efi_memory_desc(md) {
     88			int md_size = md->num_pages << EFI_PAGE_SHIFT;
     89			struct resource *res;
     90
     91			if (!(md->attribute & EFI_MEMORY_SP))
     92				continue;
     93
     94			res = kzalloc(sizeof(*res), GFP_KERNEL);
     95			if (WARN_ON(!res))
     96				break;
     97
     98			res->start	= md->phys_addr;
     99			res->end	= md->phys_addr + md_size - 1;
    100			res->name	= "Soft Reserved";
    101			res->flags	= IORESOURCE_MEM;
    102			res->desc	= IORES_DESC_SOFT_RESERVED;
    103
    104			insert_resource(&iomem_resource, res);
    105		}
    106	}
    107
    108	if (efi_runtime_disabled()) {
    109		pr_info("EFI runtime services will be disabled.\n");
    110		return 0;
    111	}
    112
    113	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
    114		pr_info("EFI runtime services access via paravirt.\n");
    115		return 0;
    116	}
    117
    118	pr_info("Remapping and enabling EFI services.\n");
    119
    120	if (!efi_virtmap_init()) {
    121		pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
    122		return -ENOMEM;
    123	}
    124
    125	/* Set up runtime services function pointers */
    126	efi_native_runtime_setup();
    127	set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
    128
    129	return 0;
    130}
    131early_initcall(riscv_enable_runtime_services);
    132
    133void efi_virtmap_load(void)
    134{
    135	preempt_disable();
    136	switch_mm(current->active_mm, &efi_mm, NULL);
    137}
    138
    139void efi_virtmap_unload(void)
    140{
    141	switch_mm(&efi_mm, current->active_mm, NULL);
    142	preempt_enable();
    143}