[PATCH] x86/boot: Use EFI setup data if provided

[Junichi Nomura]

Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
boot_params") broke kexec boot on EFI systems.  efi_get_rsdp_addr()
in the early parsing code tries to search RSDP from EFI table but
whose address is virtual.

Since kexec(1) provides physical address of config_table via boot_params,
efi_get_rsdp_addr() should look for setup_data in the same way as
efi_systab_init() in arch/x86/platform/efi/efi.c does.

Fixes: 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in boot_params")
Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
Cc: Chao Fan <fanc.fnst@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index 0ef4ad5..9f3b1b9 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -44,6 +44,22 @@ static acpi_physical_address get_acpi_rsdp(void)
 	return addr;
 }
 
+static unsigned long efi_get_setup_data_addr(void)
+{
+	struct setup_data *data;
+	u64 pa_data;
+
+	pa_data = boot_params->hdr.setup_data;
+	while (pa_data) {
+		data = (struct setup_data *) pa_data;
+		if (data->type == SETUP_EFI)
+			return pa_data + sizeof(struct setup_data);
+		pa_data = data->next;
+	}
+
+	return 0;
+}
+
 /* Search EFI system tables for RSDP. */
 static acpi_physical_address efi_get_rsdp_addr(void)
 {
@@ -53,10 +69,12 @@ static acpi_physical_address efi_get_rsdp_addr(void)
 	unsigned long systab, systab_tables, config_tables;
 	unsigned int nr_tables;
 	struct efi_info *ei;
+	struct efi_setup_data *esd;
 	bool efi_64;
 	int size, i;
 	char *sig;
 
+	esd = (struct efi_setup_data *) efi_get_setup_data_addr();
 	ei = &boot_params->efi_info;
 	sig = (char *)&ei->efi_loader_signature;
 
@@ -86,13 +104,13 @@ static acpi_physical_address efi_get_rsdp_addr(void)
 	if (efi_64) {
 		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab;
 
-		config_tables	= stbl->tables;
+		config_tables	= esd ? esd->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;
+		config_tables	= esd ? esd->tables : stbl->tables;
 		nr_tables	= stbl->nr_tables;
 		size		= sizeof(efi_config_table_32_t);
 	}