[RFC PATCH 2/4] x86/boot: Add acpitb.c to parse acpi tables

[Chao Fan]

To get more information about memory, acpi tables should be parsed.
But can't use ACPI code directely, so imitate the ACPI code to dig
the useful srat tables from ACPI tables.
Only dig the useful tables, and don't influence the initialization
of ACPI.

Signed-off-by: Chao Fan <fanc.fnst@xxxxxxxxxxxxxx>
---
 arch/x86/boot/compressed/Makefile |   1 +
 arch/x86/boot/compressed/acpitb.c | 245 ++++++++++++++++++++++++++++++
 2 files changed, 246 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 fa42f895fdde..e2b7c176a2e8 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -82,6 +82,7 @@ ifdef CONFIG_X86_64
 	vmlinux-objs-y += $(obj)/mem_encrypt.o
 	vmlinux-objs-y += $(obj)/pgtable_64.o
 endif
+vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/acpitb.o
 
 $(obj)/eboot.o: KBUILD_CFLAGS += -fshort-wchar -mno-red-zone
 
diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c
new file mode 100644
index 000000000000..9b3433fb755d
--- /dev/null
+++ b/arch/x86/boot/compressed/acpitb.c
@@ -0,0 +1,245 @@
+#include "acpitb.h"
+
+extern unsigned long get_cmd_line_ptr(void);
+
+/* Search rsdp table from efi table. */
+static bool efi_get_rsdp_addr(acpi_physical_address *rsdp_addr)
+{
+	efi_system_table_t *systab;
+	bool find_rsdp = false;
+	bool acpi_20 = false;
+	bool efi_64 = false;
+	void *config_tables;
+	struct efi_info *e;
+	char *sig;
+	int size;
+	int i;
+
+#ifndef CONFIG_EFI
+	return false;
+#endif
+
+	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. */
+#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
+
+	/* Get efi tables from systab. */
+	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 (!(efi_guidcmp(guid, ACPI_TABLE_GUID)) && !acpi_20) {
+			*rsdp_addr = (acpi_physical_address)table;
+			acpi_20 = false;
+			find_rsdp = true;
+		} else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) {
+			*rsdp_addr = (acpi_physical_address)table;
+			acpi_20 = true;
+			return true;
+		}
+	}
+	return find_rsdp;
+}
+
+static u8 checksum(u8 *buffer, u32 length)
+{
+	u8 sum = 0;
+	u8 *end = buffer + length;
+
+	while (buffer < end)
+		sum = (u8)(sum + *(buffer++));
+
+	return sum;
+}
+
+static u8 *scan_memory_for_rsdp(u8 *start_address, u32 length)
+{
+	struct acpi_table_rsdp *rsdp;
+	u8 *end_address;
+	u8 *mem_rover;
+
+	end_address = start_address + length;
+
+	for (mem_rover = start_address; mem_rover < end_address;
+	     mem_rover += ACPI_RSDP_SCAN_STEP) {
+		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;
+		return mem_rover;
+	}
+	return NULL;
+}
+
+static void bios_get_rsdp_addr(acpi_physical_address *rsdp_addr)
+{
+	struct acpi_table_rsdp *rsdp;
+	u32 physical_address;
+	u8 *table_ptr;
+	u8 *mem_rover;
+
+	table_ptr = (u8 *)ACPI_EBDA_PTR_LOCATION;
+	ACPI_MOVE_16_TO_32(&physical_address, table_ptr);
+	physical_address <<= 4;
+	table_ptr = (u8 *)(acpi_physical_address)physical_address;
+
+	if (physical_address > 0x400) {
+		mem_rover = scan_memory_for_rsdp(table_ptr,
+						 ACPI_EBDA_WINDOW_SIZE);
+
+		if (mem_rover) {
+			physical_address += (u32)ACPI_PTR_DIFF(mem_rover,
+							       table_ptr);
+			*rsdp_addr = (acpi_physical_address)physical_address;
+			return;
+		}
+	}
+
+	table_ptr = (u8 *)ACPI_HI_RSDP_WINDOW_BASE;
+	mem_rover = scan_memory_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
+
+	if (mem_rover) {
+		physical_address = (u32)(ACPI_HI_RSDP_WINDOW_BASE +
+					 ACPI_PTR_DIFF(mem_rover, table_ptr));
+		*rsdp_addr = (acpi_physical_address)physical_address;
+		return;
+	}
+}
+
+/*
+ * Used to dig rsdp table from efi table or bios.
+ * If rsdp table found in efi table, use it. Or search bios.
+ */
+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)
+{
+	struct acpi_table_desc table_descs[ACPI_MAX_TABLES];
+	char *args = (char *)get_cmd_line_ptr();
+	acpi_physical_address acpi_table;
+	acpi_physical_address root_table;
+	struct acpi_table_rsdp *rsdp;
+	struct acpi_table_header *th;
+	bool use_rsdt = false;
+	u32 table_entry_size;
+	u8 *table_entry;
+	u32 table_count;
+	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"))
+		use_rsdt = true;
+
+	if (!(use_rsdt) &&
+	    (rsdp->xsdt_physical_address) && (rsdp->revision > 1)) {
+		root_table = rsdp->xsdt_physical_address;
+		table_entry_size = ACPI_XSDT_ENTRY_SIZE;
+	} else {
+		root_table = rsdp->rsdt_physical_address;
+		table_entry_size = ACPI_RSDT_ENTRY_SIZE;
+	}
+
+	/* Get acpi root table from rsdt or xsdt. */
+	th = (struct acpi_table_header *)root_table;
+	len = th->length;
+	table_count = (u32)((len - sizeof(struct acpi_table_header)) /
+				table_entry_size);
+	table_entry = ACPI_ADD_PTR(u8, th, sizeof(struct acpi_table_header));
+
+	for (i = 0; i < table_count; i++) {
+		u64 address64;
+
+		memset(&table_descs[i], 0, sizeof(struct acpi_table_desc));
+		if (table_entry_size == ACPI_RSDT_ENTRY_SIZE)
+			acpi_table = ((acpi_physical_address)
+					(*ACPI_CAST_PTR(u32, table_entry)));
+		else {
+			ACPI_MOVE_64_TO_64(&address64, table_entry);
+			acpi_table = (acpi_physical_address) address64;
+		}
+
+		if (acpi_table) {
+			table_descs[i].address = acpi_table;
+			table_descs[i].length = sizeof(
+						struct acpi_table_header);
+			table_descs[i].pointer = (struct acpi_table_header *)
+						  acpi_table;
+			for (j = 0; j < 4; j++)
+				table_descs[i].signature.ascii[j] =
+					((struct acpi_table_header *)
+					 acpi_table)->signature[j];
+		}
+
+		if (!strncmp(table_descs[i].signature.ascii, "SRAT", 4))
+			return table_descs[i].pointer;
+
+		table_entry += table_entry_size;
+	}
+	return NULL;
+}
-- 
2.17.0