[PATCH 2/2] x86, efi: Add "efi_fake_mem" boot option
From: Taku Izumi
Date: Wed Sep 30 2015 - 00:59:16 EST
This patch introduces new boot option named "efi_fake_mem".
By specifying this parameter, you can add arbitrary attribute
to specific memory range.
This is useful for debugging of Address Range Mirroring feature.
For example, if "efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000"
is specified, the original (firmware provided) EFI memmap will be
updated so that the specified memory regions have
EFI_MEMORY_MORE_RELIABLE attribute (0x10000):
<original>
efi: mem36: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000) (129536MB)
<updated>
efi: mem36: [Conventional Memory| |MR| | | | |WB|WT|WC|UC] range=[0x0000000100000000-0x0000000180000000) (2048MB)
efi: mem37: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000000180000000-0x00000010a0000000) (61952MB)
efi: mem38: [Conventional Memory| |MR| | | | |WB|WT|WC|UC] range=[0x00000010a0000000-0x0000001120000000) (2048MB)
efi: mem39: [Conventional Memory| | | | | | |WB|WT|WC|UC] range=[0x0000001120000000-0x00000020a0000000) (63488MB)
And you will find that the following message is output:
efi: Memory: 4096M/131455M mirrored memory
Signed-off-by: Taku Izumi <izumi.taku@xxxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 15 +++
arch/x86/kernel/setup.c | 4 +-
drivers/firmware/efi/Kconfig | 22 ++++
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/fake_mem.c | 238 ++++++++++++++++++++++++++++++++++++
include/linux/efi.h | 6 +
6 files changed, 285 insertions(+), 1 deletion(-)
create mode 100644 drivers/firmware/efi/fake_mem.c
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 22a4b68..50fc09b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1094,6 +1094,21 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
you are really sure that your UEFI does sane gc and
fulfills the spec otherwise your board may brick.
+ efi_fake_mem= nn[KMG]@ss[KMG]:aa[,nn[KMG]@ss[KMG]:aa,..] [EFI; X86]
+ Add arbitrary attribute to specific memory range by
+ updating original EFI memory map.
+ Region of memory which aa attribute is added to is
+ from ss to ss+nn.
+ If efi_fake_mem=2G@4G:0x10000,2G@0x10a0000000:0x10000
+ is specified, EFI_MEMORY_MORE_RELIABLE(0x10000)
+ attribute is added to range 0x100000000-0x180000000 and
+ 0x10a0000000-0x1120000000.
+
+ Using this parameter you can do debugging of EFI memmap
+ related feature. For example, you can do debugging of
+ Address Range Mirroring feature even if your box
+ doesn't support it.
+
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index fdb7f2a..30b4c44 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1079,8 +1079,10 @@ void __init setup_arch(char **cmdline_p)
memblock_set_current_limit(ISA_END_ADDRESS);
memblock_x86_fill();
- if (efi_enabled(EFI_BOOT))
+ if (efi_enabled(EFI_BOOT)) {
+ efi_fake_memmap();
efi_find_mirror();
+ }
/*
* The EFI specification says that boot service code won't be called
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 84533e0..ac47cc4d 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -52,6 +52,28 @@ config EFI_RUNTIME_MAP
See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
+config EFI_FAKE_MEMMAP
+ bool "Enable EFI fake memory map"
+ depends on EFI && X86
+ default n
+ help
+ Saying Y here will enable "efi_fake_mem" boot option.
+ By specifying this parameter, you can add arbitrary attribute
+ to specific memory range by updating original (firmware provided)
+ EFI memmap.
+ This is useful for debugging of EFI memmap related feature.
+ e.g. Address Range Mirroring feature.
+
+config EFI_MAX_FAKE_MEM
+ int "maximum allowable number of ranges in efi_fake_mem boot option"
+ depends on EFI && X86 && EFI_FAKE_MEMMAP
+ range 1 128
+ default 8
+ help
+ Maximum allowable number of ranges in efi_fake_mem boot option.
+ Ranges can be set up to this value using comma-separated list.
+ The default value is 8.
+
config EFI_PARAMS_FROM_FDT
bool
help
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 6fd3da9..c24f005 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_UEFI_CPER) += cper.o
obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o
obj-$(CONFIG_EFI_RUNTIME_WRAPPERS) += runtime-wrappers.o
obj-$(CONFIG_EFI_STUB) += libstub/
+obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_mem.o
diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c
new file mode 100644
index 0000000..32bcb14
--- /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@xxxxxxxxxxxxxx>
+ *
+ * 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);
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 85ef051..620baec 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -908,6 +908,12 @@ extern struct kobject *efi_kobj;
extern int efi_reboot_quirk_mode;
extern bool efi_poweroff_required(void);
+#ifdef CONFIG_EFI_FAKE_MEMMAP
+extern void __init efi_fake_memmap(void);
+#else
+static inline void efi_fake_memmap(void) { }
+#endif
+
/* Iterate through an efi_memory_map */
#define for_each_efi_memory_desc(m, md) \
for ((md) = (m)->map; \
--
1.8.3.1
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