diff options
Diffstat (limited to 'drivers/firmware/efi/fake_mem.c')
| -rw-r--r-- | drivers/firmware/efi/fake_mem.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c new file mode 100644 index 000000000000..32bcb14df2c8 --- /dev/null +++ b/drivers/firmware/efi/fake_mem.c @@ -0,0 +1,238 @@ +/* + * fake_mem.c + * + * Copyright (C) 2015 FUJITSU LIMITED + * Author: Taku Izumi <izumi.taku@jp.fujitsu.com> + * + * This code introduces new boot option named "efi_fake_mem" + * By specifying this parameter, you can add arbitrary attribute to + * specific memory range by updating original (firmware provided) EFI + * memmap. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, see <http://www.gnu.org/licenses/>. + * + * The full GNU General Public License is included in this distribution in + * the file called "COPYING". + */ + +#include <linux/kernel.h> +#include <linux/efi.h> +#include <linux/init.h> +#include <linux/memblock.h> +#include <linux/types.h> +#include <linux/sort.h> +#include <asm/efi.h> + +#define EFI_MAX_FAKEMEM CONFIG_EFI_MAX_FAKE_MEM + +struct fake_mem { + struct range range; + u64 attribute; +}; +static struct fake_mem fake_mems[EFI_MAX_FAKEMEM]; +static int nr_fake_mem; + +static int __init cmp_fake_mem(const void *x1, const void *x2) +{ + const struct fake_mem *m1 = x1; + const struct fake_mem *m2 = x2; + + if (m1->range.start < m2->range.start) + return -1; + if (m1->range.start > m2->range.start) + return 1; + return 0; +} + +void __init efi_fake_memmap(void) +{ + u64 start, end, m_start, m_end, m_attr; + int new_nr_map = memmap.nr_map; + efi_memory_desc_t *md; + u64 new_memmap_phy; + void *new_memmap; + void *old, *new; + int i; + + if (!nr_fake_mem || !efi_enabled(EFI_MEMMAP)) + return; + + /* count up the number of EFI memory descriptor */ + for (old = memmap.map; old < memmap.map_end; old += memmap.desc_size) { + md = old; + start = md->phys_addr; + end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1; + + for (i = 0; i < nr_fake_mem; i++) { + /* modifying range */ + m_start = fake_mems[i].range.start; + m_end = fake_mems[i].range.end; + + if (m_start <= start) { + /* split into 2 parts */ + if (start < m_end && m_end < end) + new_nr_map++; + } + if (start < m_start && m_start < end) { + /* split into 3 parts */ + if (m_end < end) + new_nr_map += 2; + /* split into 2 parts */ + if (end <= m_end) + new_nr_map++; + } + } + } + + /* allocate memory for new EFI memmap */ + new_memmap_phy = memblock_alloc(memmap.desc_size * new_nr_map, + PAGE_SIZE); + if (!new_memmap_phy) + return; + + /* create new EFI memmap */ + new_memmap = early_memremap(new_memmap_phy, + memmap.desc_size * new_nr_map); + if (!new_memmap) { + memblock_free(new_memmap_phy, memmap.desc_size * new_nr_map); + return; + } + + for (old = memmap.map, new = new_memmap; + old < memmap.map_end; + old += memmap.desc_size, new += memmap.desc_size) { + + /* copy original EFI memory descriptor */ + memcpy(new, old, memmap.desc_size); + md = new; + start = md->phys_addr; + end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1; + + for (i = 0; i < nr_fake_mem; i++) { + /* modifying range */ + m_start = fake_mems[i].range.start; + m_end = fake_mems[i].range.end; + m_attr = fake_mems[i].attribute; + + if (m_start <= start && end <= m_end) + md->attribute |= m_attr; + + if (m_start <= start && + (start < m_end && m_end < end)) { + /* first part */ + md->attribute |= m_attr; + md->num_pages = (m_end - md->phys_addr + 1) >> + EFI_PAGE_SHIFT; + /* latter part */ + new += memmap.desc_size; + memcpy(new, old, memmap.desc_size); + md = new; + md->phys_addr = m_end + 1; + md->num_pages = (end - md->phys_addr + 1) >> + EFI_PAGE_SHIFT; + } + + if ((start < m_start && m_start < end) && m_end < end) { + /* first part */ + md->num_pages = (m_start - md->phys_addr) >> + EFI_PAGE_SHIFT; + /* middle part */ + new += memmap.desc_size; + memcpy(new, old, memmap.desc_size); + md = new; + md->attribute |= m_attr; + md->phys_addr = m_start; + md->num_pages = (m_end - m_start + 1) >> + EFI_PAGE_SHIFT; + /* last part */ + new += memmap.desc_size; + memcpy(new, old, memmap.desc_size); + md = new; + md->phys_addr = m_end + 1; + md->num_pages = (end - m_end) >> + EFI_PAGE_SHIFT; + } + + if ((start < m_start && m_start < end) && + (end <= m_end)) { + /* first part */ + md->num_pages = (m_start - md->phys_addr) >> + EFI_PAGE_SHIFT; + /* latter part */ + new += memmap.desc_size; + memcpy(new, old, memmap.desc_size); + md = new; + md->phys_addr = m_start; + md->num_pages = (end - md->phys_addr + 1) >> + EFI_PAGE_SHIFT; + md->attribute |= m_attr; + } + } + } + + /* swap into new EFI memmap */ + efi_unmap_memmap(); + memmap.map = new_memmap; + memmap.phys_map = (void *)new_memmap_phy; + memmap.nr_map = new_nr_map; + memmap.map_end = memmap.map + memmap.nr_map * memmap.desc_size; + set_bit(EFI_MEMMAP, &efi.flags); + + /* print new EFI memmap */ + efi_print_memmap(); +} + +static int __init setup_fake_mem(char *p) +{ + u64 start = 0, mem_size = 0, attribute = 0; + int i; + + if (!p) + return -EINVAL; + + while (*p != '\0') { + mem_size = memparse(p, &p); + if (*p == '@') + start = memparse(p+1, &p); + else + break; + + if (*p == ':') + attribute = simple_strtoull(p+1, &p, 0); + else + break; + + if (nr_fake_mem >= EFI_MAX_FAKEMEM) + break; + + fake_mems[nr_fake_mem].range.start = start; + fake_mems[nr_fake_mem].range.end = start + mem_size - 1; + fake_mems[nr_fake_mem].attribute = attribute; + nr_fake_mem++; + + if (*p == ',') + p++; + } + + sort(fake_mems, nr_fake_mem, sizeof(struct fake_mem), + cmp_fake_mem, NULL); + + for (i = 0; i < nr_fake_mem; i++) + pr_info("efi_fake_mem: add attr=0x%016llx to [mem 0x%016llx-0x%016llx]", + fake_mems[i].attribute, fake_mems[i].range.start, + fake_mems[i].range.end); + + return *p == '\0' ? 0 : -EINVAL; +} + +early_param("efi_fake_mem", setup_fake_mem); |