zefi: add bootargs support

Add bootargs support to zefi. This implements
get_bootargs() when both efi and bootargs are
selected in config.

Signed-off-by: Jakub Michalski <jmichalski@internships.antmicro.com>
Signed-off-by: Filip Kokosinski <fkokosinski@antmicro.com>

arch/x86/core/efi.c

@@ -18,6 +18,10 @@ static uint64_t __aligned(64) efi_stack[1024];
 
 struct efi_boot_arg *efi;
 
+#ifdef CONFIG_DYNAMIC_BOOTARGS
+__pinned_noinit char efi_bootargs[CONFIG_BOOTARGS_ARGS_BUFFER_SIZE];
+#endif
+
 void *efi_get_acpi_rsdp(void)
 {
 	if (efi == NULL) {
@@ -169,3 +173,10 @@ int arch_printk_char_out(int c)
 	return efi_console_putchar(c);
 }
 #endif
+
+#ifdef CONFIG_DYNAMIC_BOOTARGS
+const char *get_bootargs(void)
+{
+	return efi_bootargs;
+}
+#endif /* CONFIG_DYNAMIC_BOOTARGS */

arch/x86/zefi/efi.h

@@ -619,6 +619,24 @@ struct efi_system_table {
 	struct efi_configuration_table *ConfigurationTable;
 };
 
+#ifdef CONFIG_DYNAMIC_BOOTARGS
+struct efi_loaded_image_protocol {
+	uint32_t Revision;
+	void *ParentHandle;
+	struct efi_system_table *SystemTable;
+	void *DeviceHandle;
+	void *FilePath;
+	void *Reserved;
+	uint32_t LoadOptionsSize;
+	void *LoadOptions;
+	void *ImageBase;
+	uint64_t ImageSize;
+	enum efi_memory_type ImageCodeType;
+	enum efi_memory_type ImageDataType;
+	efi_unload_image_t Unload;
+};
+#endif /* CONFIG_DYNAMIC_BOOTARGS */
+
 #endif /* _ASMLANGUAGE */
 
 #endif /* ZEPHYR_INCLUDE_ARCH_X86_EFI_H_ */

arch/x86/zefi/zefi.c

@@ -32,6 +32,14 @@
 		.Data4 = { 0xbc, 0x22, 0x00, 0x80, 0xc7, 0x3c, 0x88, 0x81 }, \
 	}
 
+#define EFI_LOADED_IMAGE_PROTOCOL_GUID					\
+	{								\
+		.Data1 = 0x5b1b31a1,					\
+		.Data2 = 0x9562,					\
+		.Data3 = 0x11d2,					\
+		.Data4 = { 0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b } \
+	}
+
 /* The linker places this dummy last in the data memory.  We can't use
  * traditional linker address symbols because we're relocatable; the
  * linker doesn't know what the runtime address will be.  The compiler
@@ -135,7 +143,9 @@ static void disable_hpet(void)
  */
 uintptr_t __abi efi_entry(void *img_handle, struct efi_system_table *sys_tab)
 {
+#ifndef CONFIG_DYNAMIC_BOOTARGS
 	(void)img_handle;
+#endif /* CONFIG_DYNAMIC_BOOTARGS */
 
 	efi = sys_tab;
 	z_putchar = efi_putchar;
@@ -180,6 +190,30 @@ uintptr_t __abi efi_entry(void *img_handle, struct efi_system_table *sys_tab)
 		}
 	}
 
+#ifdef CONFIG_DYNAMIC_BOOTARGS
+	char *dst_bootargs = (char *)zefi_bootargs;
+	struct efi_loaded_image_protocol *loaded_image;
+	efi_guid_t loaded_image_protocol = EFI_LOADED_IMAGE_PROTOCOL_GUID;
+	efi_status_t loaded_image_status = sys_tab->BootServices->HandleProtocol(
+		img_handle,
+		&loaded_image_protocol,
+		(void **)&loaded_image
+	);
+
+	if (loaded_image_status == EFI_SUCCESS) {
+		uint16_t *src_bootargs = (uint16_t *)loaded_image->LoadOptions;
+
+		while (*src_bootargs != '\0' &&
+		       dst_bootargs + 1 <
+			       (char *)zefi_bootargs + CONFIG_BOOTARGS_ARGS_BUFFER_SIZE) {
+			*dst_bootargs++ = *src_bootargs++ & 0x7f;
+		}
+		*dst_bootargs = '\0';
+	} else {
+		*dst_bootargs = '\0';
+	}
+#endif /* CONFIG_DYNAMIC_BOOTARGS */
+
 	unsigned char *code = (void *)zefi_entry;
 
 	efi_arg.efi_systab = efi;

arch/x86/zefi/zefi.py

@@ -8,6 +8,9 @@ import elftools.elf.elffile
 import argparse
 
 ENTRY_SYM = "__start64"
+BOOTARGS_SYM = "efi_bootargs"
+
+args = None
 
 def verbose(msg):
     if args.verbose:
@@ -93,6 +96,9 @@ def build_elf(elf_file, include_dirs):
 
     cf.write("static uintptr_t zefi_entry = 0x%xUL;\n" % (entry_addr))
 
+    if symtab.get_symbol_by_name(BOOTARGS_SYM):
+        cf.write("static uintptr_t zefi_bootargs = 0x%xUL;\n" % (symtab.get_symbol_by_name(BOOTARGS_SYM)[0].entry.st_value))
+
     cf.close()
 
     verbose("Metadata header generated.")

kernel/Kconfig

@@ -1005,7 +1005,7 @@ config BOOTARGS
 
 config DYNAMIC_BOOTARGS
 	bool "Support dynamic bootargs"
-	depends on BOOTARGS && MULTIBOOT_INFO
+	depends on BOOTARGS && (MULTIBOOT_INFO || BUILD_OUTPUT_EFI)
 	help
 	  Enables dynamic bootargs support.