[PATCH v2 3/3] x86, efi: Add "efi_fake_mem_mirror" boot option

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This patch introduces new boot option named "efi_fake_mem_mirror".
By specifying this parameter, you can mark specific memory as
mirrored memory. This is useful for debugging of Address Range
Mirroring feature.

For example, if you specify "efi_fake_mem_mirror=2G@4G,2G@0x10a0000000",
the original (firmware provided) EFI memmap will be updated so that
the specified memory regions have EFI_MEMORY_MORE_RELIABLE attribute:

 <original EFI memmap>
   efi: mem00: [Boot Data          |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000) (0MB)
   efi: mem01: [Loader Data        |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000002000) (0MB)
   ...
   efi: mem35: [Boot Data          |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000047ee6000-0x0000000048014000) (1MB)
   efi: mem36: [Conventional Memory|  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000100000000-0x00000020a0000000) (129536MB)
   efi: mem37: [Reserved           |RT|  |  |  |  |   |  |  |  |UC] range=[0x0000000060000000-0x0000000090000000) (768MB)

 <updated EFI memmap>
   efi: mem00: [Boot Data          |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000000000-0x0000000000001000) (0MB)
   efi: mem01: [Loader Data        |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000000001000-0x0000000000002000) (0MB)
   ...
   efi: mem35: [Boot Data          |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x0000000047ee6000-0x0000000048014000) (1MB)
   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)
   efi: mem40: [Reserved           |RT|  |  |  |  |   |  |  |  |UC] range=[0x0000000060000000-0x0000000090000000) (768MB)

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 |   8 ++
 arch/x86/include/asm/efi.h          |   1 +
 arch/x86/kernel/setup.c             |   4 +-
 arch/x86/platform/efi/efi.c         |   2 +-
 drivers/firmware/efi/Kconfig        |  12 +++
 drivers/firmware/efi/Makefile       |   1 +
 drivers/firmware/efi/fake_mem.c     | 204 ++++++++++++++++++++++++++++++++++++
 include/linux/efi.h                 |   6 ++
 8 files changed, 236 insertions(+), 2 deletions(-)
 create mode 100644 drivers/firmware/efi/fake_mem.c

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1d6f045..0efded6 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1092,6 +1092,14 @@ 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_mirror=nn[KMG]@ss[KMG][,nn[KMG]@ss[KMG],..] [EFI; X86]
+			Mark specific memory as mirrored memory and update
+			EFI memory map.
+			Region of memory to be marked is from ss to ss+nn.
+			Using this parameter 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/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 155162e..479fd51 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -93,6 +93,7 @@ extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable);
 extern int __init efi_memblock_x86_reserve_range(void);
 extern pgd_t * __init efi_call_phys_prolog(void);
 extern void __init efi_call_phys_epilog(pgd_t *save_pgd);
+extern void __init print_efi_memmap(void);
 extern void __init efi_unmap_memmap(void);
 extern void __init efi_memory_uc(u64 addr, unsigned long size);
 extern void __init efi_map_region(efi_memory_desc_t *md);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 80f874b..e3ed628 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1104,8 +1104,10 @@ 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/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index e4308fe..eee8068 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -222,7 +222,7 @@ int __init efi_memblock_x86_reserve_range(void)
 	return 0;
 }
 
-static void __init print_efi_memmap(void)
+void __init print_efi_memmap(void)
 {
 #ifdef EFI_DEBUG
 	efi_memory_desc_t *md;
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 54071c1..4fafebe 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -52,6 +52,18 @@ config EFI_RUNTIME_MAP
 
 	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
 
+config EFI_FAKE_MEMMAP
+	bool "Enable EFI Fake memory mirror"
+	depends on EFI && X86
+	default n
+	help
+	  Saying Y here will enable "efi_fake_mem_miror" boot option.
+	  By specifying this parameter, you can mark specific memory as
+	  mirrored memory by updating original (firmware provided) EFI memmap.
+	  This is useful for debugging of Memory Address Range Mirroring
+	  feature.
+
+
 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..2645d4a
--- /dev/null
+++ b/drivers/firmware/efi/fake_mem.c
@@ -0,0 +1,204 @@
+/*
+ * fake_mem.c
+ *
+ * Copyright (C) 2015 FUJITSU LIMITED
+ * Author: Taku Izumi <izumi.taku@xxxxxxxxxxxxxx>
+ *
+ * This code introduces new boot option named "efi_fake_mem_mirror"
+ * By specifying this parameter, you can mark specific memory as
+ * mirrored memory 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 <asm/efi.h>
+
+#define EFI_MAX_FAKE_MIRROR 8
+static struct range fake_mirrors[EFI_MAX_FAKE_MIRROR];
+static int num_fake_mirror;
+
+void __init efi_fake_memmap(void)
+{
+	u64 start, end, m_start, m_end;
+	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 (!num_fake_mirror)
+		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 < num_fake_mirror; i++) {
+			/* mirroring range */
+			m_start = fake_mirrors[i].start;
+			m_end = fake_mirrors[i].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);
+	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 < num_fake_mirror; i++) {
+			/* mirroring range */
+			m_start = fake_mirrors[i].start;
+			m_end = fake_mirrors[i].end;
+
+			if (m_start <= start && end <= m_end)
+				md->attribute |= EFI_MEMORY_MORE_RELIABLE;
+
+			if (m_start <= start &&
+			    (start < m_end && m_end < end)) {
+				/* first part */
+				md->attribute |= EFI_MEMORY_MORE_RELIABLE;
+				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 |= EFI_MEMORY_MORE_RELIABLE;
+				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 |= EFI_MEMORY_MORE_RELIABLE;
+			}
+		}
+	}
+
+	/* 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 */
+	print_efi_memmap();
+}
+
+static int __init setup_fake_mem_mirror(char *p)
+{
+	u64 start = 0, mem_size = 0;
+	int i;
+
+	if (!p)
+		return -EINVAL;
+
+	while (*p != '\0') {
+		mem_size = memparse(p, &p);
+		if (*p == '@')
+			start = memparse(p+1, &p);
+		else
+			break;
+
+		num_fake_mirror = add_range_with_merge(fake_mirrors,
+						       EFI_MAX_FAKE_MIRROR,
+						       num_fake_mirror,
+						       start,
+						       start + mem_size - 1);
+		if (*p == ',')
+			p++;
+	}
+
+	sort_range(fake_mirrors, num_fake_mirror);
+
+	for (i = 0; i < num_fake_mirror; i++)
+		pr_info("efi_fake_mem_mirror: [mem 0x%016llx-0x%016llx] marked as mirrored memory",
+			fake_mirrors[i].start, fake_mirrors[i].end);
+
+	return *p == '\0' ? 0 : -EINVAL;
+}
+
+early_param("efi_fake_mem_mirror", setup_fake_mem_mirror);
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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