acpitable解析过程分析

acpitable解析过程分析acpi表结构⼤概是这样的知道了表的⼤概结构我问来分析的解析的过程解析的⼊⼝函数为acpi_tb_parse_root_table函数/*********************************************************************************FUNCTION:acpi_tb_parse_root_table**PARAMETERS:rsdp*-PointertotheRSDP*RETURN:*Status*DESCRIPTION:ThisfunctioniscalledtoparsetheRootSystemDescription*Table(RSDTorXSDT)**NOTE:Tablesaremapped(notcopied)forefficiency.TheFACSmustbemappedandcannotbecopiedbecauseitcontainstheactualmemorylocationoftheACPIGlobalLock.*********************************************************************************/acpi_status__initacpi_tb_parse_root_table(acpi_physical_addressrsdp_address){structacpi_table_rsdp*rsdp;u32table_entry_size;u32i;u32table_count;structacpi_table_header*table;acpi_physical_addressaddress;u32length;u8*table_entry;acpi_statusstatus;u32table_index;ACPI_FUNCTION_TRACE(tb_parse_root_table);/*MaptheentireRSDPandextracttheaddressoftheRSDTorXSDT*/rsdp=acpi_os_map_memory(rsdp_address,sizeof(structacpi_table_rsdp));if(!rsdp){return_ACPI_STATUS(AE_NO_MEMORY);}acpi_tb_print_table_header(rsdp_address,ACPI_CAST_PTR(structacpi_table_header,rsdp));/*UseXSDTifpresentandnotoverridden.Otherwise,useRSDT*/if((rsdp->revision>1)&&if((rsdp->revision>1)&&rsdp->xsdt_physical_address&&!acpi_gbl_do_not_use_xsdt){/**RSDPcontainsanXSDT(64-bitphysicaladdresses).Wemustuse*theXSDTiftherevisionis>1andtheXSDTpointerispresent,*aspertheACPIspecification.*/address=(acpi_physical_address)rsdp->xsdt_physical_address;table_entry_size=ACPI_XSDT_ENTRY_SIZE;}else{/*RoottableisanRSDT(32-bitphysicaladdresses)*/address=(acpi_physical_address)rsdp->rsdt_physical_address;table_entry_size=ACPI_RSDT_ENTRY_SIZE;}/**Itisnotpossibletomapmorethanoneentryinsomeenvironments,*sounmaptheRSDPherebeforemappingothertables*/acpi_os_unmap_memory(rsdp,sizeof(structacpi_table_rsdp));/*MaptheRSDT/XSDTtableheadertogetthefulltablelength*/table=acpi_os_map_memory(address,sizeof(structacpi_table_header));if(!table){return_ACPI_STATUS(AE_NO_MEMORY);}acpi_tb_print_table_header(address,table);/**Validatelengthofthetable,andmapentiretable.*Minimumlengthtablemustcontainatleastoneentry.*/length=table->length;acpi_os_unmap_memory(table,sizeof(structacpi_table_header));if(length<(sizeof(structacpi_table_header)+table_entry_size)){ACPI_BIOS_ERROR((AE_INFO,"Invalidtablelength0x%XinRSDT/XSDT",length));return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);}table=acpi_os_map_memory(address,length);if(!table){return_ACPI_STATUS(AE_NO_MEMORY);}/*Validatetheroottablechecksum*/status=acpi_tb_verify_checksum(table,length);if(ACPI_FAILURE(status)){acpi_os_unmap_memory(table,length);return_ACPI_STATUS(status);}/*Getthenumberofentriesandpointertofirstentry*/table_count=(u32)((table->length-sizeof(structacpi_table_header))/table_entry_size);table_entry=ACPI_ADD_PTR(u8,table,sizeof(structacpi_table_header));/**FirstthreeentriesinthetablearrayarereservedfortheDSDT*FirstthreeentriesinthetablearrayarereservedfortheDSDT*and32bit/64bitFACS,whicharenotactuallypresentinthe*RSDT/XSDT-theycomefromtheFADT*/acpi_gbl_root_table_list.current_table_count=3;/*InitializetheroottablearrayfromtheRSDT/XSDT*/for(i=0;i<table_count;i++){/*Getthetablephysicaladdress(32-bitforRSDT,64-bitforXSDT)*/address=acpi_tb_get_root_table_entry(table_entry,table_entry_size);/*SkipNULLentriesinRSDT/XSDT*/if(!address){gotonext_table;}status=acpi_tb_install_standard_table(address,ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,FALSE,TRUE,&table_index);if(ACPI_SUCCESS(status)&&ACPI_COMPARE_NAME(&acpi_gbl_root_table_list.tables[table_index].signature,ACPI_SIG_FADT)){acpi_tb_parse_fadt(table_index);}next_table:table_entry+=table_entry_size;}acpi_os_unmap_memory(table,length);return_ACPI_STATUS(AE_OK);}⾸先注释上说acpi表为了⾼效使⽤map映射，⽽FACS必须使⽤映射因为这段内存中存在全局锁1rsdp=acpi_os_map_memory(rsdp_address,sizeof(structacpi_table_rsdp));映射到虚拟地址RSDP2acpi_tb_print_table_header打印表头表头结构如下，注意表头是直接从rsdp转换得到的/*********************************************************************************MasterACPITableHeader.ThiscommonheaderisusedbyallACPItables*excepttheRSDPandFACS.*******************************************************************************/structacpi_table_header{charsignature[ACPI_NAME_SIZE];/*ASCIItablesignature*/u32length;/*Lengthoftableinbytes,includingthisheader*/u8revision;/*ACPISpecificationminorversionnumber*//*Tomakesumofentiretable==0*/u8checksum;charoem_id[ACPI_OEM_ID_SIZE];/*ASCIIOEMidentification*/charoem_table_id[ACPI_OEM_TABLE_ID_SIZE];/*ASCIIOEMtableidentification*/u32oem_revision;/*OEMrevisionnumber*/charasl_compiler_id[ACPI_NAME_SIZE];/*ASCIIASLcompilervendorID*/u32asl_compiler_revision;/*ASLcompilerversion*/};第⼀项signature是表的签名length为表的长度revision版本checksum校验值oem_id⼚商idoem_table_idtable的idoem_revision⼚商版本asl_compiler_id编译器idasl_compiler_revision编译器版本编译是为解释acpi操作语⾔ASL的编译器3根据版本选择使⽤xsdt还是rsdt，revision>1并且存在xsdt的情况必须使⽤XSDTXSDT表全称ExtendedRootSystemDescriptionTable,它的作⽤于RSDT⼀样，区别在于两者包含的指针地址⼀个是32位的，⼀个是64位的。XSDT表结构如下typedefstruct{EFI_ACPI_DESCRIPTION_HEADERHeader;UINT64Entry;RSDT结构如下typedefstruct{EFI_ACPI_DESCRIPTION_HEADERHeader;UINT32}Entry;4找到要具体使⽤的RSDT/XSDT就可以进⾏解析了，⾸先解除RSDP的映射，然后映射RSDT/XSDT表头，通过表头验证表长度是否正确，如果正确再映射整张表5验证表校验和6处表头后为entry，获取entry个数，able_count=(u32)((table->length-sizeof(structacpi_table_header))/table_entry_size)7acpi_gbl_root_table_list.current_table_count=3该值设置为3的理由是保留前三项⽤于存放DSDT和FACS，这两个表不是从RSDT和XSDT中获取的，⽽是从FADT中得到的8按照计算好的表项个数去遍历RSDT/XSDTacpi_tb_get_root_table_entry函数⽤于获取⼀个entryacpi_tb_install_standard_table⽤于安装标准table如果table是FADT则使⽤acpi_tb_parse_fadt函数去解析DSDT和FACS下⾯具体分析下acpi_tb_get_root_table_entry函数，acpi_tb_install_standard_table和acpi_tb_parse_fadtacpi_tb_get_root_table_entry⽤于从RSDT/XSDT中解析⼦table注意RSDT/XSDT的entry变量描述的就是⼦table的物理地址/*********************************************************************************FUNCTION:acpi_tb_get_root_table_entry**PARAMETERS:table_entry-PointertotheRSDT/XSDTtableentry**table_entry_size-sizeof32or64(RSDTorXSDT)*RETURN:*Physicaladdressextractedfromtheroottable*DESCRIPTION:Getoneroottableentry.Handles32-bitand64-bitcaseson*both32-bitand64-bitplatforms**NOTE:acpi_physical_addressis32-biton32-bitplatforms,64-biton64-bitplatforms.********************************************************************************/staticacpi_physical_addressacpi_tb_get_root_table_entry(u8*table_entry,u32table_entry_size){u64address64;/**Getthetablephysicaladdress(32-bitforRSDT,64-bitforXSDT):*Note:Addressesare32-bitaligned(not64)inbothRSDTandXSDT*/if(table_entry_size==ACPI_RSDT_ENTRY_SIZE){/**32-bitplatform,RSDT:Return32-bittableentry*64-bitplatform,RSDT:Expand32-bitto64-bitandreturn*/return((acpi_physical_address)(*ACPI_CAST_PTR(u32,table_entry)));}else{/**32-bitplatform,XSDT:Truncate64-bitto32-bitandreturn*64-bitplatform,XSDT:Move(unaligned)64-bittolocal,*return64-bit*/ACPI_MOVE_64_TO_64(&address64,table_entry);#ifACPI_MACHINE_WIDTH==32if(address64>ACPI_UINT32_MAX){/*Willtruncate64-bitaddressto32bits,issuewarning*/ACPI_BIOS_WARNING((AE_INFO,"64-bitPhysicalAddressinXSDTistoolarge(0x%8.8X%8.8X),""truncating",ACPI_FORMAT_UINT64(address64)));}#endifreturn((acpi_physical_address)(address64));}}其实很简单，就是按照RSDT(32位entry)或者XDDT(64位entry)转换⼀下。acpi_tb_install_standard_table函数⽤于安装前⾯解析到的tableentry指向的table/*******************************************************************************/*********************************************************************************FUNCTION:acpi_tb_install_standard_table**PARAMETERS:address-Addressofthetable(mightbeavirtual******addressdependingonthetable_flags)flags-Flagsforthetablereload-Whetherreloadshouldbeperformed-Whetheroverrideshouldbeperformed-Wherethetableindexisreturnedoverridetable_index*RETURN:*Status*DESCRIPTION:ThisfunctioniscalledtoinstallanACPItablethatis******neitherDSDTnorFACS(a"standard"table.)Whenthisfunctioniscalledby"Load"or"LoadTable"opcodes,orbyacpi_load_table()API,the"Reload"parameterisset.Aftersucessfullyreturningfromthisfunction,tableis"INSTALLED"butnot"VALIDATED".******************************************************************************/acpi_statusacpi_tb_install_standard_table(acpi_physical_addressaddress,u8flags,u8reload,u8override,u32*table_index){u32i;acpi_statusstatus=AE_OK;structacpi_table_descnew_table_desc;ACPI_FUNCTION_TRACE(tb_install_standard_table);/*Acquireatemporarytabledescriptorforvalidation*/status=acpi_tb_acquire_temp_table(&new_table_desc,address,flags);if(ACPI_FAILURE(status)){ACPI_ERROR((AE_INFO,"Couldnotacquiretablelengthat%8.8X%8.8X",ACPI_FORMAT_UINT64(address)));return_ACPI_STATUS(status);}/**OptionallydonotloadanySSDTsfromtheRSDT/XSDT.Thiscan*beusefulfordebuggingACPIproblemsonsomemachines.*/if(!reload&&acpi_gbl_disable_ssdt_table_install&&ACPI_COMPARE_NAME(&new_table_desc.signature,ACPI_SIG_SSDT)){"Ignoringinstallationof%4.4sat%8.8X%8.8X",new_table_desc.signature.ascii,ACPI_INFO((AE_INFO,ACPI_FORMAT_UINT64(address)));gotorelease_and_exit;}/*Validateandverifyatablebeforeinstallation*/status=acpi_tb_verify_temp_table(&new_table_desc,NULL);if(ACPI_FAILURE(status)){gotorelease_and_exit;}*Validatetheincomingtablesignature.**1)Originally,wecheckedthetablesignaturefor"SSDT"or"PSDT".tables,signature"OEM".*2)WeaddedsupportforOEMx*3)Validtableswereencounteredwithanullsignature,sowejust*gaveuponvalidatingthesignature,(05/2008).*4)Weencounterednon-AMLtablessuchastheMADT,whichcausedfaults.Sonow,weonceagainallow*interpretererrorsandkernel*only"SSDT","OEMx",andnow,alsoanullsignature.(05/2011).*/if((new_table_desc.signature.ascii[0]!=0x00)&&(!ACPI_COMPARE_NAME(&new_table_desc.signature,ACPI_SIG_SSDT))&&(ACPI_STRNCMP(new_table_desc.signature.ascii,"OEM",3)))ACPI_BIOS_ERROR((AE_INFO,"Tablehasinvalidsignature[%4.4s](0x%8.8X),""mustbeSSDTorOEMx",{acpi_ut_valid_acpi_name(new_table_desc.signature.ascii)?new_table_desc.signature.ascii:"",new_table_eger));status=AE_BAD_SIGNATURE;gotorelease_and_exit;}/*Checkiftableisalreadyregistered*/for(i=0;i<acpi_gbl_root_table_list.current_table_count;++i){/**Checkforatablematchontheentiretablelength,*notjusttheheader.*/if(!acpi_tb_compare_tables(&new_table_desc,i)){continue;}/**Note:thecurrentmechanismdoesnotunregisteratableifitis*dynamicallyunloaded.Therelatednamespaceentriesaredeleted,tablelist.*butthetableremainsintheroot**Theassumptionhereisthatthenumberofdifferenttablesthat*willbeloadedisactuallysmall,andthereisminimaloverhead*injustkeepingthetableincaseitisneededagain.**Ifthisassumptionchangesinthefuture(perhapsonlarge*machineswithmanytableload/unloadoperations),tableswill*needtobeunregisteredwhentheyareunloaded,andslotsintheempty.*roottablelistshouldbereusedwhen*/if(acpi_gbl_root_table_list.tables[i].flags&ACPI_TABLE_IS_LOADED){/*Tableisstillloaded,thisisanerror*/status=AE_ALREADY_EXISTS;gotorelease_and_exit;}else{*AswearegoingtoreturnAE_OKtothecaller,weshould*taketheresponsibilityoffreeingtheinputdescriptor.*Refilltheinputdescriptortoensure*acpi_tb_install_table_with_override()canbecalledagainto*indicatethere-installation.*/acpi_tb_uninstall_table(&new_table_desc);*table_index=i;return_ACPI_STATUS(AE_OK);}}}/*Addthetabletotheglobalroottablelist*/status=acpi_tb_get_next_root_index(&i);if(ACPI_FAILURE(status)){gotorelease_and_exit;}*table_index=i;acpi_tb_install_table_with_override(i,&new_table_desc,override);release_and_exit:/*Releasethetemporarytabledescriptor*/acpi_tb_release_temp_table(&new_table_desc);return_ACPI_STATUS(status);}这是⼀个⽐较凶恶的函数，代码很长1acpi_tb_acquire_temp_table⽤于创建⼀个acpi_table_desc结构，acpi_table_desc定义如下structacpi_table_desc{acpi_physical_addressaddress;structacpi_table_header*pointer;u32length;/*Lengthfixedat32bits(fixedintableheader)*/unionacpi_name_unionsignature;acpi_owner_idowner_id;u8flags;};主要描述了table的物理地址，table头地址和table长度，签名以及标志2acpi_tb_verify_temp_table验证table是否可⽤，主要验证包括签名，checksum，长度等信息3reload表⽰重新加载，要先卸载原来的再加载当前的4acpi_tb_install_table_with_override安装/*********************************************************************************FUNCTION:acpi_tb_install_table_with_override**PARAMETERS:table_index-Indexintoroottablearray-Newtabledescriptortoinstall***new_table_descoverride-Whetheroverrideshouldbeperformed*RETURN:*None*DESCRIPTION:InstallanACPItableintotheglobaldatastructure.The****tableoverridemechanismiscalledtoallowthehostOStoreplaceanytablebeforeitisinstalledintheroottablearray.******************************************************************************/voidacpi_tb_install_table_with_override(u32table_index,structacpi_table_desc*new_table_desc,u8override){if(table_index>=acpi_gbl_root_table_list.current_table_count){return;}/**ACPITableOverride:**Beforeweinstallthetable,letthehostOSoverrideitwithanew*oneifdesired.AnytablewithintheRSDT/XSDTcanbereplaced,*includingtheDSDTwhichispointedtobytheFADT.*/if(override){acpi_tb_override_table(new_table_desc);}acpi_tb_init_table_descriptor(&acpi_gbl_root_table_list.tables[table_index],new_table_desc->address,new_table_desc->flags,new_table_desc->pointer);acpi_tb_print_table_header(new_table_desc->address,new_table_desc->pointer);/*Settheglobalintegerwidth(baseduponrevisionoftheDSDT)*/if(table_index==ACPI_TABLE_INDEX_DSDT){acpi_ut_set_integer_width(new_table_desc->pointer->revision);}}1如果覆盖参数为真，则⽤新表覆盖⽼表acpi_tb_override_table2acpi_tb_init_table_descriptor初始化表,注意这⾥的参数是&acpi_gbl_root_table_list.tables[table_index]，也就是把table_descriptor安装到acpi_gbl_root_table_list.tables数组就算安装完成了acpi_tb_parse_fadt函数去解析DSDT和FACS/*********************************************************************************PARAMETERS:table_index*-IndexfortheFADT*RETURN:*None*DESCRIPTION:InitializetheFADT,DSDTandFACStables**(FADTcontainstheaddressesoftheDSDTandFACS)*********************************************************************