[RFC] x86/efi: Drop support for fake EFI memory maps

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 11e57ba2985c..90c64525e7e1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1450,27 +1450,6 @@ 
 			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,EARLY]
-			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.
-
-			If efi_fake_mem=8G@9G:0x40000 is specified, the
-			EFI_MEMORY_SP(0x40000) attribute is added to
-			range 0x240000000-0x43fffffff.
-
-			Using this parameter you can do debugging of EFI memmap
-			related features. For example, you can do debugging of
-			Address Range Mirroring feature even if your box
-			doesn't support it, or mark specific memory as
-			"soft reserved".
-
 	efivar_ssdt=	[EFI; X86] Name of an EFI variable that contains an SSDT
 			that is to be dynamically loaded by Linux. If there are
 			multiple variables with the same name but with different
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d7122a1883e..0c31f65aeb1d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2038,26 +2038,6 @@  config EFI_MIXED
 
 	  If unsure, say N.
 
-config EFI_FAKE_MEMMAP
-	bool "Enable EFI fake memory map"
-	depends on EFI
-	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_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_RUNTIME_MAP
 	bool "Export EFI runtime maps to sysfs" if EXPERT
 	depends on EFI
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index dec961c6d16a..f4d82379bf44 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -119,13 +119,8 @@  char *skip_spaces(const char *str)
 #include "../../../../lib/ctype.c"
 #include "../../../../lib/cmdline.c"
 
-enum parse_mode {
-	PARSE_MEMMAP,
-	PARSE_EFI,
-};
-
 static int
-parse_memmap(char *p, u64 *start, u64 *size, enum parse_mode mode)
+parse_memmap(char *p, u64 *start, u64 *size)
 {
 	char *oldp;
 
@@ -148,29 +143,11 @@  parse_memmap(char *p, u64 *start, u64 *size, enum parse_mode mode)
 		*start = memparse(p + 1, &p);
 		return 0;
 	case '@':
-		if (mode == PARSE_MEMMAP) {
-			/*
-			 * memmap=nn@ss specifies usable region, should
-			 * be skipped
-			 */
-			*size = 0;
-		} else {
-			u64 flags;
-
-			/*
-			 * efi_fake_mem=nn@ss:attr the attr specifies
-			 * flags that might imply a soft-reservation.
-			 */
-			*start = memparse(p + 1, &p);
-			if (p && *p == ':') {
-				p++;
-				if (kstrtoull(p, 0, &flags) < 0)
-					*size = 0;
-				else if (flags & EFI_MEMORY_SP)
-					return 0;
-			}
-			*size = 0;
-		}
+		/*
+		 * memmap=nn@ss specifies usable region, should
+		 * be skipped
+		 */
+		*size = 0;
 		fallthrough;
 	default:
 		/*
@@ -185,7 +162,7 @@  parse_memmap(char *p, u64 *start, u64 *size, enum parse_mode mode)
 	return -EINVAL;
 }
 
-static void mem_avoid_memmap(enum parse_mode mode, char *str)
+static void mem_avoid_memmap(char *str)
 {
 	static int i;
 
@@ -200,7 +177,7 @@  static void mem_avoid_memmap(enum parse_mode mode, char *str)
 		if (k)
 			*k++ = 0;
 
-		rc = parse_memmap(str, &start, &size, mode);
+		rc = parse_memmap(str, &start, &size);
 		if (rc < 0)
 			break;
 		str = k;
@@ -281,7 +258,7 @@  static void handle_mem_options(void)
 			break;
 
 		if (!strcmp(param, "memmap")) {
-			mem_avoid_memmap(PARSE_MEMMAP, val);
+			mem_avoid_memmap(val);
 		} else if (IS_ENABLED(CONFIG_X86_64) && strstr(param, "hugepages")) {
 			parse_gb_huge_pages(param, val);
 		} else if (!strcmp(param, "mem")) {
@@ -295,8 +272,6 @@  static void handle_mem_options(void)
 
 			if (mem_size < mem_limit)
 				mem_limit = mem_size;
-		} else if (!strcmp(param, "efi_fake_mem")) {
-			mem_avoid_memmap(PARSE_EFI, val);
 		}
 	}
 
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 481096177500..b3e4d999b913 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -384,23 +384,8 @@  static inline void efi_reserve_boot_services(void)
 }
 #endif /* CONFIG_EFI */
 
-#ifdef CONFIG_EFI_FAKE_MEMMAP
-extern void __init efi_fake_memmap_early(void);
-extern void __init efi_fake_memmap(void);
-#else
-static inline void efi_fake_memmap_early(void)
-{
-}
-
-static inline void efi_fake_memmap(void)
-{
-}
-#endif
-
 extern int __init efi_memmap_alloc(unsigned int num_entries,
 				   struct efi_memory_map_data *data);
-extern void __efi_memmap_free(u64 phys, unsigned long size,
-			      unsigned long flags);
 
 extern int __init efi_memmap_install(struct efi_memory_map_data *data);
 extern int __init efi_memmap_split_count(efi_memory_desc_t *md,
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 05c5aa951da7..282e8577ac7b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -995,7 +995,6 @@  void __init setup_arch(char **cmdline_p)
 	mem_encrypt_setup_arch();
 	cc_random_init();
 
-	efi_fake_memmap();
 	efi_find_mirror();
 	efi_esrt_init();
 	efi_mokvar_table_init();
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index f090ec972d7b..88a96816de9a 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -226,8 +226,6 @@  int __init efi_memblock_x86_reserve_range(void)
 	if (add_efi_memmap || do_efi_soft_reserve())
 		do_add_efi_memmap();
 
-	efi_fake_memmap_early();
-
 	WARN(efi.memmap.desc_version != 1,
 	     "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
 	     efi.memmap.desc_version);
diff --git a/arch/x86/platform/efi/fake_mem.c b/arch/x86/platform/efi/fake_mem.c
deleted file mode 100644
index 41d57cad3d84..000000000000
--- a/arch/x86/platform/efi/fake_mem.c
+++ /dev/null
@@ -1,197 +0,0 @@ 
-// SPDX-License-Identifier: GPL-2.0
-/*
- * 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.
- */
-
-#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/e820/api.h>
-#include <asm/efi.h>
-
-#define EFI_MAX_FAKEMEM CONFIG_EFI_MAX_FAKE_MEM
-
-static struct efi_mem_range efi_fake_mems[EFI_MAX_FAKEMEM];
-static int nr_fake_mem;
-
-static int __init cmp_fake_mem(const void *x1, const void *x2)
-{
-	const struct efi_mem_range *m1 = x1;
-	const struct efi_mem_range *m2 = x2;
-
-	if (m1->range.start < m2->range.start)
-		return -1;
-	if (m1->range.start > m2->range.start)
-		return 1;
-	return 0;
-}
-
-static void __init efi_fake_range(struct efi_mem_range *efi_range)
-{
-	struct efi_memory_map_data data = { 0 };
-	int new_nr_map = efi.memmap.nr_map;
-	efi_memory_desc_t *md;
-	void *new_memmap;
-
-	/* count up the number of EFI memory descriptor */
-	for_each_efi_memory_desc(md)
-		new_nr_map += efi_memmap_split_count(md, &efi_range->range);
-
-	/* allocate memory for new EFI memmap */
-	if (efi_memmap_alloc(new_nr_map, &data) != 0)
-		return;
-
-	/* create new EFI memmap */
-	new_memmap = early_memremap(data.phys_map, data.size);
-	if (!new_memmap) {
-		__efi_memmap_free(data.phys_map, data.size, data.flags);
-		return;
-	}
-
-	efi_memmap_insert(&efi.memmap, new_memmap, efi_range);
-
-	/* swap into new EFI memmap */
-	early_memunmap(new_memmap, data.size);
-
-	efi_memmap_install(&data);
-}
-
-void __init efi_fake_memmap(void)
-{
-	int i;
-
-	if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
-		return;
-
-	for (i = 0; i < nr_fake_mem; i++)
-		efi_fake_range(&efi_fake_mems[i]);
-
-	/* 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;
-
-		efi_fake_mems[nr_fake_mem].range.start = start;
-		efi_fake_mems[nr_fake_mem].range.end = start + mem_size - 1;
-		efi_fake_mems[nr_fake_mem].attribute = attribute;
-		nr_fake_mem++;
-
-		if (*p == ',')
-			p++;
-	}
-
-	sort(efi_fake_mems, nr_fake_mem, sizeof(struct efi_mem_range),
-	     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]",
-			efi_fake_mems[i].attribute, efi_fake_mems[i].range.start,
-			efi_fake_mems[i].range.end);
-
-	return *p == '\0' ? 0 : -EINVAL;
-}
-
-early_param("efi_fake_mem", setup_fake_mem);
-
-void __init efi_fake_memmap_early(void)
-{
-	int i;
-
-	/*
-	 * The late efi_fake_mem() call can handle all requests if
-	 * EFI_MEMORY_SP support is disabled.
-	 */
-	if (!efi_soft_reserve_enabled())
-		return;
-
-	if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
-		return;
-
-	/*
-	 * Given that efi_fake_memmap() needs to perform memblock
-	 * allocations it needs to run after e820__memblock_setup().
-	 * However, if efi_fake_mem specifies EFI_MEMORY_SP for a given
-	 * address range that potentially needs to mark the memory as
-	 * reserved prior to e820__memblock_setup(). Update e820
-	 * directly if EFI_MEMORY_SP is specified for an
-	 * EFI_CONVENTIONAL_MEMORY descriptor.
-	 */
-	for (i = 0; i < nr_fake_mem; i++) {
-		struct efi_mem_range *mem = &efi_fake_mems[i];
-		efi_memory_desc_t *md;
-		u64 m_start, m_end;
-
-		if ((mem->attribute & EFI_MEMORY_SP) == 0)
-			continue;
-
-		m_start = mem->range.start;
-		m_end = mem->range.end;
-		for_each_efi_memory_desc(md) {
-			u64 start, end, size;
-
-			if (md->type != EFI_CONVENTIONAL_MEMORY)
-				continue;
-
-			start = md->phys_addr;
-			end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;
-
-			if (m_start <= end && m_end >= start)
-				/* fake range overlaps descriptor */;
-			else
-				continue;
-
-			/*
-			 * Trim the boundary of the e820 update to the
-			 * descriptor in case the fake range overlaps
-			 * !EFI_CONVENTIONAL_MEMORY
-			 */
-			start = max(start, m_start);
-			end = min(end, m_end);
-			size = end - start + 1;
-
-			if (end <= start)
-				continue;
-
-			/*
-			 * Ensure each efi_fake_mem instance results in
-			 * a unique e820 resource
-			 */
-			e820__range_remove(start, size, E820_TYPE_RAM, 1);
-			e820__range_add(start, size, E820_TYPE_SOFT_RESERVED);
-			e820__update_table(e820_table);
-		}
-	}
-}
diff --git a/arch/x86/platform/efi/memmap.c b/arch/x86/platform/efi/memmap.c
index 6ed1935504b9..061b8ecc71a1 100644
--- a/arch/x86/platform/efi/memmap.c
+++ b/arch/x86/platform/efi/memmap.c
@@ -30,6 +30,7 @@  static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
 	return PFN_PHYS(page_to_pfn(p));
 }
 
+static
 void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
 {
 	if (flags & EFI_MEMMAP_MEMBLOCK) {
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 1983fd3bf392..68df27bd71c9 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -781,7 +781,7 @@  static const char *cmdline_memmap_override;
 static efi_status_t parse_options(const char *cmdline)
 {
 	static const char opts[][14] = {
-		"mem=", "memmap=", "efi_fake_mem=", "hugepages="
+		"mem=", "memmap=", "hugepages="
 	};
 
 	for (int i = 0; i < ARRAY_SIZE(opts); i++) {