Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:
 "Most of the changes center around the difficult problem of KASLR
  pinning down hot-removable memory regions. At the very early stage
  KASRL is making irreversible kernel address layout decisions we don't
  have full knowledge about the memory maps yet.

  So the changes from Chao Fan add this (parsing the RSDP table early),
  together with fixes from Borislav Petkov"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot/compressed/64: Do not read legacy ROM on EFI system
  x86/boot: Correct RSDP parsing with 32-bit EFI
  x86/kexec: Fill in acpi_rsdp_addr from the first kernel
  x86/boot: Fix randconfig build error due to MEMORY_HOTREMOVE
  x86/boot: Fix cmdline_find_option() prototype visibility
  x86/boot/KASLR: Limit KASLR to extract the kernel in immovable memory only
  x86/boot: Parse SRAT table and count immovable memory regions
  x86/boot: Early parse RSDP and save it in boot_params
  x86/boot: Search for RSDP in memory
  x86/boot: Search for RSDP in the EFI tables
  x86/boot: Add "acpi_rsdp=" early parsing
  x86/boot: Copy kstrtoull() to boot/string.c
  x86/boot: Build the command line parsing code unconditionally

1 files changed, 338 insertions, 0 deletions

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
new file mode 100644
index 000000000000..0ef4ad55b29b
--- /dev/null
+++ b/arch/x86/boot/compressed/acpi.c
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0
+#define BOOT_CTYPE_H
+#include "misc.h"
+#include "error.h"
+#include "../string.h"
+
+#include <linux/numa.h>
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+/*
+ * Longest parameter of 'acpi=' is 'copy_dsdt', plus an extra '\0'
+ * for termination.
+ */
+#define MAX_ACPI_ARG_LENGTH 10
+
+/*
+ * Immovable memory regions representation. Max amount of memory regions is
+ * MAX_NUMNODES*2.
+ */
+struct mem_vector immovable_mem[MAX_NUMNODES*2];
+
+/*
+ * Max length of 64-bit hex address string is 19, prefix "0x" + 16 hex
+ * digits, and '\0' for termination.
+ */
+#define MAX_ADDR_LEN 19
+
+static acpi_physical_address get_acpi_rsdp(void)
+{
+	acpi_physical_address addr = 0;
+
+#ifdef CONFIG_KEXEC
+	char val[MAX_ADDR_LEN] = { };
+	int ret;
+
+	ret = cmdline_find_option("acpi_rsdp", val, MAX_ADDR_LEN);
+	if (ret < 0)
+		return 0;
+
+	if (kstrtoull(val, 16, &addr))
+		return 0;
+#endif
+	return addr;
+}
+
+/* Search EFI system tables for RSDP. */
+static acpi_physical_address efi_get_rsdp_addr(void)
+{
+	acpi_physical_address rsdp_addr = 0;
+
+#ifdef CONFIG_EFI
+	unsigned long systab, systab_tables, config_tables;
+	unsigned int nr_tables;
+	struct efi_info *ei;
+	bool efi_64;
+	int size, i;
+	char *sig;
+
+	ei = &boot_params->efi_info;
+	sig = (char *)&ei->efi_loader_signature;
+
+	if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
+		efi_64 = true;
+	} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
+		efi_64 = false;
+	} else {
+		debug_putstr("Wrong EFI loader signature.\n");
+		return 0;
+	}
+
+	/* Get systab from boot params. */
+#ifdef CONFIG_X86_64
+	systab = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32);
+#else
+	if (ei->efi_systab_hi || ei->efi_memmap_hi) {
+		debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n");
+		return 0;
+	}
+	systab = ei->efi_systab;
+#endif
+	if (!systab)
+		error("EFI system table not found.");
+
+	/* Handle EFI bitness properly */
+	if (efi_64) {
+		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab;
+
+		config_tables	= stbl->tables;
+		nr_tables	= stbl->nr_tables;
+		size		= sizeof(efi_config_table_64_t);
+	} else {
+		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab;
+
+		config_tables	= stbl->tables;
+		nr_tables	= stbl->nr_tables;
+		size		= sizeof(efi_config_table_32_t);
+	}
+
+	if (!config_tables)
+		error("EFI config tables not found.");
+
+	/* Get EFI tables from systab. */
+	for (i = 0; i < nr_tables; i++) {
+		acpi_physical_address table;
+		efi_guid_t guid;
+
+		config_tables += size;
+
+		if (efi_64) {
+			efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables;
+
+			guid  = tbl->guid;
+			table = tbl->table;
+
+			if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
+				debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
+				return 0;
+			}
+		} else {
+			efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables;
+
+			guid  = tbl->guid;
+			table = tbl->table;
+		}
+
+		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
+			rsdp_addr = table;
+		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
+			return table;
+	}
+#endif
+	return rsdp_addr;
+}
+
+static u8 compute_checksum(u8 *buffer, u32 length)
+{
+	u8 *end = buffer + length;
+	u8 sum = 0;
+
+	while (buffer < end)
+		sum += *(buffer++);
+
+	return sum;
+}
+
+/* Search a block of memory for the RSDP signature. */
+static u8 *scan_mem_for_rsdp(u8 *start, u32 length)
+{
+	struct acpi_table_rsdp *rsdp;
+	u8 *address, *end;
+
+	end = start + length;
+
+	/* Search from given start address for the requested length */
+	for (address = start; address < end; address += ACPI_RSDP_SCAN_STEP) {
+		/*
+		 * Both RSDP signature and checksum must be correct.
+		 * Note: Sometimes there exists more than one RSDP in memory;
+		 * the valid RSDP has a valid checksum, all others have an
+		 * invalid checksum.
+		 */
+		rsdp = (struct acpi_table_rsdp *)address;
+
+		/* BAD Signature */
+		if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature))
+			continue;
+
+		/* Check the standard checksum */
+		if (compute_checksum((u8 *)rsdp, ACPI_RSDP_CHECKSUM_LENGTH))
+			continue;
+
+		/* Check extended checksum if table version >= 2 */
+		if ((rsdp->revision >= 2) &&
+		    (compute_checksum((u8 *)rsdp, ACPI_RSDP_XCHECKSUM_LENGTH)))
+			continue;
+
+		/* Signature and checksum valid, we have found a real RSDP */
+		return address;
+	}
+	return NULL;
+}
+
+/* Search RSDP address in EBDA. */
+static acpi_physical_address bios_get_rsdp_addr(void)
+{
+	unsigned long address;
+	u8 *rsdp;
+
+	/* Get the location of the Extended BIOS Data Area (EBDA) */
+	address = *(u16 *)ACPI_EBDA_PTR_LOCATION;
+	address <<= 4;
+
+	/*
+	 * Search EBDA paragraphs (EBDA is required to be a minimum of
+	 * 1K length)
+	 */
+	if (address > 0x400) {
+		rsdp = scan_mem_for_rsdp((u8 *)address, ACPI_EBDA_WINDOW_SIZE);
+		if (rsdp)
+			return (acpi_physical_address)(unsigned long)rsdp;
+	}
+
+	/* Search upper memory: 16-byte boundaries in E0000h-FFFFFh */
+	rsdp = scan_mem_for_rsdp((u8 *) ACPI_HI_RSDP_WINDOW_BASE,
+					ACPI_HI_RSDP_WINDOW_SIZE);
+	if (rsdp)
+		return (acpi_physical_address)(unsigned long)rsdp;
+
+	return 0;
+}
+
+/* Return RSDP address on success, otherwise 0. */
+acpi_physical_address get_rsdp_addr(void)
+{
+	acpi_physical_address pa;
+
+	pa = get_acpi_rsdp();
+
+	if (!pa)
+		pa = boot_params->acpi_rsdp_addr;
+
+	if (!pa)
+		pa = efi_get_rsdp_addr();
+
+	if (!pa)
+		pa = bios_get_rsdp_addr();
+
+	return pa;
+}
+
+#if defined(CONFIG_RANDOMIZE_BASE) && defined(CONFIG_MEMORY_HOTREMOVE)
+/* Compute SRAT address from RSDP. */
+static unsigned long get_acpi_srat_table(void)
+{
+	unsigned long root_table, acpi_table;
+	struct acpi_table_header *header;
+	struct acpi_table_rsdp *rsdp;
+	u32 num_entries, size, len;
+	char arg[10];
+	u8 *entry;
+
+	rsdp = (struct acpi_table_rsdp *)(long)boot_params->acpi_rsdp_addr;
+	if (!rsdp)
+		return 0;
+
+	/* Get ACPI root table from RSDP.*/
+	if (!(cmdline_find_option("acpi", arg, sizeof(arg)) == 4 &&
+	    !strncmp(arg, "rsdt", 4)) &&
+	    rsdp->xsdt_physical_address &&
+	    rsdp->revision > 1) {
+		root_table = rsdp->xsdt_physical_address;
+		size = ACPI_XSDT_ENTRY_SIZE;
+	} else {
+		root_table = rsdp->rsdt_physical_address;
+		size = ACPI_RSDT_ENTRY_SIZE;
+	}
+
+	if (!root_table)
+		return 0;
+
+	header = (struct acpi_table_header *)root_table;
+	len = header->length;
+	if (len < sizeof(struct acpi_table_header) + size)
+		return 0;
+
+	num_entries = (len - sizeof(struct acpi_table_header)) / size;
+	entry = (u8 *)(root_table + sizeof(struct acpi_table_header));
+
+	while (num_entries--) {
+		if (size == ACPI_RSDT_ENTRY_SIZE)
+			acpi_table = *(u32 *)entry;
+		else
+			acpi_table = *(u64 *)entry;
+
+		if (acpi_table) {
+			header = (struct acpi_table_header *)acpi_table;
+
+			if (ACPI_COMPARE_NAME(header->signature, ACPI_SIG_SRAT))
+				return acpi_table;
+		}
+		entry += size;
+	}
+	return 0;
+}
+
+/**
+ * count_immovable_mem_regions - Parse SRAT and cache the immovable
+ * memory regions into the immovable_mem array.
+ *
+ * Return the number of immovable memory regions on success, 0 on failure:
+ *
+ * - Too many immovable memory regions
+ * - ACPI off or no SRAT found
+ * - No immovable memory region found.
+ */
+int count_immovable_mem_regions(void)
+{
+	unsigned long table_addr, table_end, table;
+	struct acpi_subtable_header *sub_table;
+	struct acpi_table_header *table_header;
+	char arg[MAX_ACPI_ARG_LENGTH];
+	int num = 0;
+
+	if (cmdline_find_option("acpi", arg, sizeof(arg)) == 3 &&
+	    !strncmp(arg, "off", 3))
+		return 0;
+
+	table_addr = get_acpi_srat_table();
+	if (!table_addr)
+		return 0;
+
+	table_header = (struct acpi_table_header *)table_addr;
+	table_end = table_addr + table_header->length;
+	table = table_addr + sizeof(struct acpi_table_srat);
+
+	while (table + sizeof(struct acpi_subtable_header) < table_end) {
+		sub_table = (struct acpi_subtable_header *)table;
+		if (sub_table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) {
+			struct acpi_srat_mem_affinity *ma;
+
+			ma = (struct acpi_srat_mem_affinity *)sub_table;
+			if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) && ma->length) {
+				immovable_mem[num].start = ma->base_address;
+				immovable_mem[num].size = ma->length;
+				num++;
+			}
+
+			if (num >= MAX_NUMNODES*2) {
+				debug_putstr("Too many immovable memory regions, aborting.\n");
+				return 0;
+			}
+		}
+		table += sub_table->length;
+	}
+	return num;
+}
+#endif /* CONFIG_RANDOMIZE_BASE && CONFIG_MEMORY_HOTREMOVE */