Date:   Tue, 7 Aug 2018 14:49:58 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     <tglx@...utronix.de>, <mingo@...hat.com>, <hpa@...or.com>,
        <x86@...nel.org>, <linux-kernel@...r.kernel.org>,
        <keescook@...omium.org>, <bhe@...hat.com>,
        <n-horiguchi@...jp.nec.com>
CC:     <indou.takao@...fujitsu.com>, <caoj.fnst@...fujitsu.com>,
        <douly.fnst@...fujitsu.com>, Chao Fan <fanc.fnst@...fujitsu.com>
Subject: [PATCH v5 2/4] x86/boot: Add acpitb.c to parse acpi tables

Imitate the ACPI code to parse ACPI tables. Functions are simplified
cause some operations are not needed here.
And also, this method won't influence the initialization of ACPI.

Signed-off-by: Chao Fan <fanc.fnst@...fujitsu.com>
---
 arch/x86/boot/compressed/Makefile |   4 +
 arch/x86/boot/compressed/acpitb.c | 272 ++++++++++++++++++++++++++++++
 2 files changed, 276 insertions(+)
 create mode 100644 arch/x86/boot/compressed/acpitb.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 169c2feda14a..a382bb50f599 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -83,6 +83,10 @@ ifdef CONFIG_X86_64
 	vmlinux-objs-y += $(obj)/pgtable_64.o
 endif
 
+ifdef CONFIG_MEMORY_HOTREMOVE
+vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/acpitb.o
+endif
+
 $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone
 
 vmlinux-objs-$(CONFIG_EFI_STUB) += $(obj)/eboot.o $(obj)/efi_stub_$(BITS).o \
diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c
new file mode 100644
index 000000000000..a1ec0d9313fe
--- /dev/null
+++ b/arch/x86/boot/compressed/acpitb.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0
+#define BOOT_CTYPE_H
+#include "misc.h"
+#include "acpitb.h"
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+#include <linux/numa.h>
+
+extern unsigned long get_cmd_line_ptr(void);
+
+#ifdef CONFIG_EFI
+/* Search EFI table for rsdp table. */
+static bool efi_get_rsdp_addr(acpi_physical_address *rsdp_addr)
+{
+	efi_system_table_t *systab;
+	bool find_rsdp = false;
+	bool efi_64 = false;
+	void *config_tables;
+	struct efi_info *e;
+	char *sig;
+	int size;
+	int i;
+
+	e = &boot_params->efi_info;
+	sig = (char *)&e->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 false;
+	}
+
+	/* Get systab from boot params. Based on efi_init(). */
+#ifdef CONFIG_X86_32
+	if (e->efi_systab_hi || e->efi_memmap_hi) {
+		debug_putstr("Table located above 4GB, disabling EFI.\n");
+		return false;
+	}
+	systab = (efi_system_table_t *)e->efi_systab;
+#else
+	systab = (efi_system_table_t *)(
+			e->efi_systab | ((__u64)e->efi_systab_hi<<32));
+#endif
+
+	if (systab == NULL)
+		return false;
+
+	/*
+	 * Get EFI tables from systab. Based on efi_config_init() and
+	 * efi_config_parse_tables(). Only dig the useful tables but not
+	 * do the initialization jobs.
+	 */
+	size = efi_64 ? sizeof(efi_config_table_64_t) :
+			sizeof(efi_config_table_32_t);
+
+	for (i = 0; i < systab->nr_tables; i++) {
+		efi_guid_t guid;
+		unsigned long table;
+
+		config_tables = (void *)(systab->tables + size * i);
+		if (efi_64) {
+			efi_config_table_64_t *tmp_table;
+
+			tmp_table = (efi_config_table_64_t *)config_tables;
+			guid = tmp_table->guid;
+			table = tmp_table->table;
+#ifndef CONFIG_64BIT
+			if (table >> 32) {
+				debug_putstr("Table located above 4G, disabling EFI.\n");
+				return false;
+			}
+#endif
+		} else {
+			efi_config_table_32_t *tmp_table;
+
+			tmp_table = (efi_config_table_32_t *)config_tables;
+			guid = tmp_table->guid;
+			table = tmp_table->table;
+		}
+
+		/*
+		 * Get rsdp from EFI tables.
+		 * If ACPI20 table found, use it and return true.
+		 * If ACPI20 table not found, but ACPI table found,
+		 * use the ACPI table and return true.
+		 * If neither ACPI table nor ACPI20 table found,
+		 * return false.
+		 */
+		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID))) {
+			*rsdp_addr = (acpi_physical_address)table;
+			find_rsdp = true;
+		} else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) {
+			*rsdp_addr = (acpi_physical_address)table;
+			return true;
+		}
+	}
+	return find_rsdp;
+}
+#else
+static bool efi_get_rsdp_addr(acpi_physical_address *rsdp_addr)
+{
+	return false;
+}
+#endif
+
+static u8 checksum(u8 *buffer, u32 length)
+{
+	u8 sum = 0;
+	u8 *end = buffer + length;
+
+	while (buffer < end)
+		sum = (u8)(sum + *(buffer++));
+
+	return sum;
+}
+
+/*
+ * Used to search a block of memory for the RSDP signature.
+ * Return Pointer to the RSDP if found, otherwise NULL.
+ * Based on acpi_tb_scan_memory_for_rsdp().
+ */
+static u8 *scan_mem_for_rsdp(u8 *start_address, u32 length)
+{
+	struct acpi_table_rsdp *rsdp;
+	u8 *end_address;
+	u8 *mem_rover;
+
+	end_address = start_address + length;
+
+	/* Search from given start address for the requested length */
+	for (mem_rover = start_address; mem_rover < end_address;
+	     mem_rover += ACPI_RSDP_SCAN_STEP) {
+		/* The RSDP signature and checksum must both be correct */
+		rsdp = (struct acpi_table_rsdp *)mem_rover;
+		if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature))
+			continue;
+		if (checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
+			continue;
+		if ((rsdp->revision >= 2) &&
+		    (checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
+			continue;
+
+		/* Sig and checksum valid, we have found a real RSDP */
+		return mem_rover;
+	}
+	return NULL;
+}
+
+/*
+ * Used to search RSDP physical address.
+ * Based on acpi_find_root_pointer(). Since only use physical address
+ * in this period, so there is no need to do the memory map jobs.
+ */
+static void bios_get_rsdp_addr(acpi_physical_address *rsdp_addr)
+{
+	struct acpi_table_rsdp *rsdp;
+	u8 *table_ptr;
+	u8 *mem_rover;
+	u32 address;
+
+	/* Get the location of the Extended BIOS Data Area (EBDA) */
+	table_ptr = (u8 *)ACPI_EBDA_PTR_LOCATION;
+	*(u32 *)(void *)&address = *(u16 *)(void *)table_ptr;
+	address <<= 4;
+	table_ptr = (u8 *)(acpi_physical_address)address;
+
+	/*
+	 * Search EBDA paragraphs (EBDA is required to be a minimum of
+	 * 1K length)
+	 */
+	if (address > 0x400) {
+		mem_rover = scan_mem_for_rsdp(table_ptr, ACPI_EBDA_WINDOW_SIZE);
+
+		if (mem_rover) {
+			address += (u32)ACPI_PTR_DIFF(mem_rover, table_ptr);
+			*rsdp_addr = (acpi_physical_address)address;
+			return;
+		}
+	}
+
+	table_ptr = (u8 *)ACPI_HI_RSDP_WINDOW_BASE;
+	mem_rover = scan_mem_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
+
+	/*
+	 * Search upper memory: 16-byte boundaries in E0000h-FFFFFh
+	 */
+	if (mem_rover) {
+		address = (u32)(ACPI_HI_RSDP_WINDOW_BASE +
+				ACPI_PTR_DIFF(mem_rover, table_ptr));
+		*rsdp_addr = (acpi_physical_address)address;
+		return;
+	}
+}
+
+/*
+ * Used to dig rsdp table from EFI table or BIOS.
+ * If rsdp table found in EFI table, use it. Or search BIOS.
+ * Based on acpi_os_get_root_pointer().
+ */
+static acpi_physical_address get_rsdp_addr(void)
+{
+	acpi_physical_address pa = 0;
+	bool status = false;
+
+	status = efi_get_rsdp_addr(&pa);
+
+	if (!status || pa == 0)
+		bios_get_rsdp_addr(&pa);
+
+	return pa;
+}
+
+struct acpi_table_header *get_acpi_srat_table(void)
+{
+	char *args = (char *)get_cmd_line_ptr();
+	acpi_physical_address acpi_table;
+	acpi_physical_address root_table;
+	struct acpi_table_header *header;
+	struct acpi_table_rsdp *rsdp;
+	char *signature;
+	u8 *entry;
+	u32 count;
+	u32 size;
+	int i, j;
+	u32 len;
+
+	rsdp = (struct acpi_table_rsdp *)get_rsdp_addr();
+	if (!rsdp)
+		return NULL;
+
+	/* Get rsdt or xsdt from rsdp. */
+	if (!strstr(args, "acpi=rsdt") &&
+	    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;
+	}
+
+	/* Get ACPI root table from rsdt or xsdt.*/
+	header = (struct acpi_table_header *)root_table;
+	len = header->length;
+	count = (u32)((len - sizeof(struct acpi_table_header)) / size);
+	entry = ACPI_ADD_PTR(u8, header, sizeof(struct acpi_table_header));
+
+	for (i = 0; i < count; i++) {
+		u64 address64;
+
+		if (size == ACPI_RSDT_ENTRY_SIZE)
+			acpi_table = ((acpi_physical_address)
+				      (*ACPI_CAST_PTR(u32, entry)));
+		else {
+			*(u64 *)(void *)&address64 = *(u64 *)(void *)entry;
+			acpi_table = (acpi_physical_address) address64;
+		}
+
+		if (acpi_table) {
+			header = (struct acpi_table_header *)acpi_table;
+			signature = header->signature;
+
+			if (!strncmp(signature, "SRAT", 4))
+				return header;
+		}
+		entry += size;
+	}
+	return NULL;
+}
-- 
2.17.1

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