uefi+arm64+acpi 组合时boot_command_line的获取

2019-11-09 16:16:57

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在efi_entry 中会通过下面的code从uefi中拿到cmdline cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size); if (!cmdline_ptr) { PR_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL/n"); goto fail; }char *efi_convert_cmdline(efi_system_table_t *sys_table_arg, efi_loaded_image_t *image, int *cmd_line_len){ const u16 *s2; u8 *s1 = NULL; unsigned long cmdline_addr = 0; int load_options_chars = image->load_options_size / 2; /* UTF-16 */ const u16 *options = image->load_options; int options_bytes = 0; /* UTF-8 bytes */ int options_chars = 0; /* UTF-16 chars */ efi_status_t status; u16 zero = 0; if (options) { s2 = options; while (*s2 && *s2 != '/n' && options_chars < load_options_chars) { options_bytes += efi_utf8_bytes(*s2++); options_chars++; } } if (!options_chars) { /* No command line options, so return empty string*/ options = &zero; } options_bytes++; /* NUL termination */ status = efi_high_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr, MAX_CMDLINE_ADDRESS); if (status != EFI_SUCCESS) return NULL; s1 = (u8 *)cmdline_addr; s2 = (const u16 *)options; s1 = efi_utf16_to_utf8(s1, s2, options_chars); *s1 = '/0'; *cmd_line_len = options_bytes; return (char *)cmdline_addr;}在efi_convert_cmdline 的image代表loaded image的protoc status = sys_table->boottime->handle_protocol(handle, &loaded_image_proto, (void *)&image);然后在efi_convert_cmdline中首先image->load_options 拿到cmdline，然后将cmdline从utf16转成utf8返回。然后会在allocate_new_fdt_and_exit_boot -> update_fdt中将cmdline_ptr中的内容copy到chosen中efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt, unsigned long orig_fdt_size, void *fdt, int new_fdt_size, char *cmdline_ptr, u64 initrd_addr, u64 initrd_size, efi_memory_desc_t *memory_map, unsigned long map_size, unsigned long desc_size, u32 desc_ver){ num_rsv = fdt_num_mem_rsv(fdt); while (num_rsv-- > 0) fdt_del_mem_rsv(fdt, num_rsv); node = fdt_subnode_offset(fdt, 0, "chosen"); if (node < 0) { node = fdt_add_subnode(fdt, 0, "chosen"); if (node < 0) { status = node; /* node is error code when negative */ goto fdt_set_fail; } } if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) { status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr, strlen(cmdline_ptr) + 1); if (status) goto fdt_set_fail; }}在update_fdt中可以看到是通过fdt_setprop 将cmdline_ptr 中的内容copy到chosen节点中的bootargs中.

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