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src/include/compiler.h
960 строк
30 KB
Michael Brown
[build] Allow binaries to request a log partition from genfsimg
26 мар 2026, 18:12
26 мар 2026, 18:12
646d4b0
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#ifndef COMPILER_H #define COMPILER_H /* * Doxygen can't cope with some of the more esoteric areas of C, so we * make its life simpler. * */ #ifdef DOXYGEN #define __attribute__(x) #endif /** @file * * Global compiler definitions. * * This file is implicitly included by every @c .c file in Etherboot. * It defines global macros such as DBG(). * * We arrange for each object to export the symbol @c obj_OBJECT * (where @c OBJECT is the object name, e.g. @c rtl8139) as a global * symbol, so that the linker can drag in selected object files from * the library using <tt> -u obj_OBJECT </tt>. * */ /* Force visibility of all symbols to "hidden", i.e. inform gcc that * all symbol references resolve strictly within our final binary. * This avoids unnecessary PLT/GOT entries on x86_64. * * This is a stronger claim than specifying "-fvisibility=hidden", * since it also affects symbols marked with "extern". */ #ifndef ASSEMBLY #if __GNUC__ >= 4 #pragma GCC visibility push(hidden) #endif #endif /* ASSEMBLY */ #undef _S1 #undef _S2 #undef _C1 #undef _C2 /** Concatenate non-expanded arguments */ #define _C1( x, y ) x ## y /** Concatenate expanded arguments */ #define _C2( x, y ) _C1 ( x, y ) /** Stringify non-expanded argument */ #define _S1( x ) #x /** Stringify expanded argument */ #define _S2( x ) _S1 ( x ) /* Assembler section types */ #ifdef ASSEMBLY #define PROGBITS _C2 ( ASM_TCHAR, progbits ) #define NOBITS _C2 ( ASM_TCHAR, nobits ) #else #define PROGBITS_OPS _S2 ( ASM_TCHAR_OPS ) "progbits" #define PROGBITS _S2 ( ASM_TCHAR ) "progbits" #define NOBITS_OPS _S2 ( ASM_TCHAR_OPS ) "nobits" #define NOBITS _S2 ( ASM_TCHAR ) "nobits" #endif /** * @defgroup symmacros Macros to provide or require explicit symbols * @{ */ /** * Provide a symbol within this object file * * @v symbol Symbol name */ #ifdef ASSEMBLY #define PROVIDE_SYMBOL( symbol ) \ .section ".provided", "a", NOBITS ; \ .hidden symbol ; \ .globl symbol ; \ symbol: ; \ .previous #else #define PROVIDE_SYMBOL( symbol ) \ char symbol[0] \ __attribute__ (( section ( ".provided" ) )) #endif /** * Request a symbol * * @v symbol Symbol name * * Request a symbol to be included within the link. If the symbol * cannot be found, the link will succeed anyway. */ #ifdef ASSEMBLY #define REQUEST_SYMBOL( symbol ) \ .equ __request_ ## symbol, symbol #else #define REQUEST_SYMBOL( symbol ) \ __asm__ ( ".equ __request_" #symbol ", " #symbol ) #endif /** * Require a symbol * * @v symbol Symbol name * * Require a symbol to be included within the link. If the symbol * cannot be found, the link will fail. * * To use this macro within a file, you must also specify the file's * "requiring symbol" using the REQUIRING_SYMBOL() or * PROVIDE_REQUIRING_SYMBOL() macros. */ #ifdef ASSEMBLY #define REQUIRE_SYMBOL( symbol ) \ .reloc __requiring_symbol__, RELOC_TYPE_NONE, symbol #else #define REQUIRE_SYMBOL( symbol ) \ __asm__ ( ".reloc __requiring_symbol__, " \ _S2 ( RELOC_TYPE_NONE ) ", " #symbol ) #endif /** * Specify the file's requiring symbol * * @v symbol Symbol name * * REQUIRE_SYMBOL() works by defining a dummy relocation record * against a nominated "requiring symbol". The presence of the * nominated requiring symbol will drag in all of the symbols * specified using REQUIRE_SYMBOL(). */ #ifdef ASSEMBLY #define REQUIRING_SYMBOL( symbol ) \ .equ __requiring_symbol__, symbol #else #define REQUIRING_SYMBOL( symbol ) \ __asm__ ( ".equ __requiring_symbol__, " #symbol ) #endif /** * Provide a file's requiring symbol * * If the file contains no symbols that can be used as the requiring * symbol, you can provide a dummy one-byte-long symbol using * PROVIDE_REQUIRING_SYMBOL(). */ #ifdef ASSEMBLY #define PROVIDE_REQUIRING_SYMBOL() \ .section ".tbl.requiring_symbols", "a", PROGBITS ; \ __requiring_symbol__: .byte 0 ; \ .size __requiring_symbol__, . - __requiring_symbol__ ; \ .previous #else #define PROVIDE_REQUIRING_SYMBOL() \ __asm__ ( ".section \".tbl.requiring_symbols\", " \ " \"a\", " PROGBITS "\n" \ "__requiring_symbol__:\t.byte 0\n" \ ".size __requiring_symbol__, " \ " . - __requiring_symbol__\n" \ ".previous" ) #endif /** @} */ /** * @defgroup ipxenote Macros to provide ELF notes * @{ */ /* Construct an iPXE-specific ELF note */ #define IPXE_NOTE( type ) \ __asm__ ( ".section \".note.ipxe\", \"\", " \ _S2 ( ASM_TCHAR ) "note\n\t" \ /* Owner name length */ \ ".long 4\n\t" \ /* Content length */ \ ".long 0\n\t" \ /* Type */ \ ".long " _S2 ( _C2 ( IPXE_NOTE_, type ) ) \ "\n\t" \ /* Owner name */ \ ".ascii \"iPXE\"\n\t" \ ".previous\n\t" ) /** Build will use a disk-based console log, if present */ #define IPXE_NOTE_DISKLOG 0x18aed109 /** @} */ /** * @defgroup objmacros Macros to provide or require explicit objects * @{ */ #define PREFIX_OBJECT( _prefix ) _C2 ( _prefix, OBJECT ) #define OBJECT_SYMBOL PREFIX_OBJECT ( obj_ ) /** Always provide the symbol for the current object (defined by -DOBJECT) */ PROVIDE_SYMBOL ( OBJECT_SYMBOL ); /** * Request an object * * @v object Object name * * Request an object to be included within the link. If the object * cannot be found, the link will succeed anyway. */ #define REQUEST_OBJECT( object ) REQUEST_SYMBOL ( obj_ ## object ) /** * Require an object * * @v object Object name * * Require an object to be included within the link. If the object * cannot be found, the link will fail. * * To use this macro within a file, you must also specify the file's * "requiring symbol" using the REQUIRING_SYMBOL() or * PROVIDE_REQUIRING_SYMBOL() macros. */ #define REQUIRE_OBJECT( object ) REQUIRE_SYMBOL ( obj_ ## object ) /** @} */ /** Select file identifier for errno.h (if used) */ #define ERRFILE PREFIX_OBJECT ( ERRFILE_ ) #ifndef ASSEMBLY /** Declare a function as weak (use *before* the definition) * * Due to a bug in at least GCC 4.4.4 and earlier, weak symbols may be * inlined if they have hidden visibility (see above for why hidden * visibility is used). This results in the non-weak symbol never * being used, so explicitly mark the function as noinline to prevent * inlining. */ #define __weak __attribute__ (( weak, noinline )) #endif /** @defgroup dbg Debugging infrastructure * @{ */ /** @def DBG * * Print a debugging message. * * The debug level is set at build time by specifying the @c DEBUG= * parameter on the @c make command line. For example, to enable * debugging for the PCI bus functions (in pci.c) in a @c .dsk image * for the @c rtl8139 card, you could use the command line * * @code * * make bin/rtl8139.dsk DEBUG=pci * * @endcode * * This will enable the debugging statements (DBG()) in pci.c. If * debugging is not enabled, DBG() statements will be ignored. * * You can enable debugging in several objects simultaneously by * separating them with commas, as in * * @code * * make bin/rtl8139.dsk DEBUG=pci,buffer,heap * * @endcode * * You can increase the debugging level for an object by specifying it * with @c :N, where @c N is the level, as in * * @code * * make bin/rtl8139.dsk DEBUG=pci,buffer:2,heap * * @endcode * * which would enable debugging for the PCI, buffer-handling and * heap-allocation code, with the buffer-handling code at level 2. * */ #ifndef DBGLVL_MAX #define NDEBUG #define DBGLVL_MAX 0 #endif #ifndef DBGLVL_DFLT #define DBGLVL_DFLT DBGLVL_MAX #endif #ifndef ASSEMBLY /** printf() for debugging */ extern void __attribute__ (( format ( printf, 1, 2 ) )) dbg_printf ( const char *fmt, ... ); extern void dbg_autocolourise ( unsigned long id ); extern void dbg_decolourise ( void ); extern void dbg_hex_dump_da ( unsigned long dispaddr, const void *data, unsigned long len ); extern void dbg_md5_da ( unsigned long dispaddr, const void *data, unsigned long len ); extern void dbg_pause ( void ); extern void dbg_more ( void ); /* Allow for selective disabling of enabled debug levels */ #define __debug_disable( object ) _C2 ( __debug_disable_, object ) char __debug_disable(OBJECT) = ( DBGLVL_MAX & ~DBGLVL_DFLT ); #define DBG_DISABLE_OBJECT( object, level ) do { \ extern char __debug_disable(object); \ __debug_disable(object) |= (level); \ } while ( 0 ) #define DBG_ENABLE_OBJECT( object, level ) do { \ extern char __debug_disable(object); \ __debug_disable(object) &= ~(level); \ } while ( 0 ) #if DBGLVL_MAX #define DBGLVL ( DBGLVL_MAX & ~__debug_disable(OBJECT) ) #define DBG_DISABLE( level ) do { \ __debug_disable(OBJECT) |= ( (level) & DBGLVL_MAX ); \ } while ( 0 ) #define DBG_ENABLE( level ) do { \ __debug_disable(OBJECT) &= ~( (level) & DBGLVL_MAX ); \ } while ( 0 ) #else #define DBGLVL 0 #define DBG_DISABLE( level ) do { } while ( 0 ) #define DBG_ENABLE( level ) do { } while ( 0 ) #endif #define DBGLVL_LOG 1 #define DBG_LOG ( DBGLVL & DBGLVL_LOG ) #define DBGLVL_EXTRA 2 #define DBG_EXTRA ( DBGLVL & DBGLVL_EXTRA ) #define DBGLVL_PROFILE 4 #define DBG_PROFILE ( DBGLVL & DBGLVL_PROFILE ) #define DBGLVL_IO 8 #define DBG_IO ( DBGLVL & DBGLVL_IO ) /** * Print debugging message if we are at a certain debug level * * @v level Debug level * @v ... printf() argument list */ #define DBG_IF( level, ... ) do { \ if ( DBG_ ## level ) { \ dbg_printf ( __VA_ARGS__ ); \ } \ } while ( 0 ) /** * Print a hex dump if we are at a certain debug level * * @v level Debug level * @v dispaddr Display address * @v data Data to print * @v len Length of data */ #define DBG_HDA_IF( level, dispaddr, data, len ) do { \ if ( DBG_ ## level ) { \ union { \ unsigned long ul; \ typeof ( dispaddr ) raw; \ } da; \ da.ul = 0; \ da.raw = dispaddr; \ dbg_hex_dump_da ( da.ul, data, len ); \ } \ } while ( 0 ) /** * Print a hex dump if we are at a certain debug level * * @v level Debug level * @v data Data to print * @v len Length of data */ #define DBG_HD_IF( level, data, len ) do { \ const void *_data = data; \ DBG_HDA_IF ( level, _data, _data, len ); \ } while ( 0 ) /** * Print an MD5 checksum if we are at a certain debug level * * @v level Debug level * @v dispaddr Display address * @v data Data to print * @v len Length of data */ #define DBG_MD5A_IF( level, dispaddr, data, len ) do { \ if ( DBG_ ## level ) { \ union { \ unsigned long ul; \ typeof ( dispaddr ) raw; \ } da; \ da.ul = 0; \ da.raw = dispaddr; \ dbg_md5_da ( da.ul, data, len ); \ } \ } while ( 0 ) /** * Print an MD5 checksum if we are at a certain debug level * * @v level Debug level * @v data Data to print * @v len Length of data */ #define DBG_MD5_IF( level, data, len ) do { \ const void *_data = data; \ DBG_MD5A_IF ( level, _data, _data, len ); \ } while ( 0 ) /** * Prompt for key press if we are at a certain debug level * * @v level Debug level */ #define DBG_PAUSE_IF( level, ... ) do { \ if ( DBG_ ## level ) { \ dbg_pause(); \ } \ } while ( 0 ) /** * Prompt for more output data if we are at a certain debug level * * @v level Debug level */ #define DBG_MORE_IF( level, ... ) do { \ if ( DBG_ ## level ) { \ dbg_more(); \ } \ } while ( 0 ) /** * Select colour for debug messages if we are at a certain debug level * * @v level Debug level * @v id Message stream ID */ #define DBG_AC_IF( level, id ) do { \ if ( DBG_ ## level ) { \ union { \ unsigned long ul; \ typeof ( id ) raw; \ } dbg_stream; \ dbg_stream.ul = 0; \ dbg_stream.raw = id; \ dbg_autocolourise ( dbg_stream.ul ); \ } \ } while ( 0 ) /** * Revert colour for debug messages if we are at a certain debug level * * @v level Debug level */ #define DBG_DC_IF( level ) do { \ if ( DBG_ ## level ) { \ dbg_decolourise(); \ } \ } while ( 0 ) /* Autocolourising versions of the DBGxxx_IF() macros */ #define DBGC_IF( level, id, ... ) do { \ DBG_AC_IF ( level, id ); \ DBG_IF ( level, __VA_ARGS__ ); \ DBG_DC_IF ( level ); \ } while ( 0 ) #define DBGC_HDA_IF( level, id, ... ) do { \ DBG_AC_IF ( level, id ); \ DBG_HDA_IF ( level, __VA_ARGS__ ); \ DBG_DC_IF ( level ); \ } while ( 0 ) #define DBGC_HD_IF( level, id, ... ) do { \ DBG_AC_IF ( level, id ); \ DBG_HD_IF ( level, __VA_ARGS__ ); \ DBG_DC_IF ( level ); \ } while ( 0 ) #define DBGC_MD5A_IF( level, id, ... ) do { \ DBG_AC_IF ( level, id ); \ DBG_MD5A_IF ( level, __VA_ARGS__ ); \ DBG_DC_IF ( level ); \ } while ( 0 ) #define DBGC_MD5_IF( level, id, ... ) do { \ DBG_AC_IF ( level, id ); \ DBG_MD5_IF ( level, __VA_ARGS__ ); \ DBG_DC_IF ( level ); \ } while ( 0 ) #define DBGC_PAUSE_IF( level, id ) do { \ DBG_AC_IF ( level, id ); \ DBG_PAUSE_IF ( level ); \ DBG_DC_IF ( level ); \ } while ( 0 ) #define DBGC_MORE_IF( level, id ) do { \ DBG_AC_IF ( level, id ); \ DBG_MORE_IF ( level ); \ DBG_DC_IF ( level ); \ } while ( 0 ) /* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( LOG, ... )*/ #define DBG( ... ) DBG_IF ( LOG, ##__VA_ARGS__ ) #define DBG_HDA( ... ) DBG_HDA_IF ( LOG, ##__VA_ARGS__ ) #define DBG_HD( ... ) DBG_HD_IF ( LOG, ##__VA_ARGS__ ) #define DBG_MD5A( ... ) DBG_MD5A_IF ( LOG, ##__VA_ARGS__ ) #define DBG_MD5( ... ) DBG_MD5_IF ( LOG, ##__VA_ARGS__ ) #define DBG_PAUSE( ... ) DBG_PAUSE_IF ( LOG, ##__VA_ARGS__ ) #define DBG_MORE( ... ) DBG_MORE_IF ( LOG, ##__VA_ARGS__ ) #define DBGC( ... ) DBGC_IF ( LOG, ##__VA_ARGS__ ) #define DBGC_HDA( ... ) DBGC_HDA_IF ( LOG, ##__VA_ARGS__ ) #define DBGC_HD( ... ) DBGC_HD_IF ( LOG, ##__VA_ARGS__ ) #define DBGC_MD5A( ... ) DBGC_MD5A_IF ( LOG, ##__VA_ARGS__ ) #define DBGC_MD5( ... ) DBGC_MD5_IF ( LOG, ##__VA_ARGS__ ) #define DBGC_PAUSE( ... ) DBGC_PAUSE_IF ( LOG, ##__VA_ARGS__ ) #define DBGC_MORE( ... ) DBGC_MORE_IF ( LOG, ##__VA_ARGS__ ) /* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( EXTRA, ... )*/ #define DBG2( ... ) DBG_IF ( EXTRA, ##__VA_ARGS__ ) #define DBG2_HDA( ... ) DBG_HDA_IF ( EXTRA, ##__VA_ARGS__ ) #define DBG2_HD( ... ) DBG_HD_IF ( EXTRA, ##__VA_ARGS__ ) #define DBG2_MD5A( ... ) DBG_MD5A_IF ( EXTRA, ##__VA_ARGS__ ) #define DBG2_MD5( ... ) DBG_MD5_IF ( EXTRA, ##__VA_ARGS__ ) #define DBG2_PAUSE( ... ) DBG_PAUSE_IF ( EXTRA, ##__VA_ARGS__ ) #define DBG2_MORE( ... ) DBG_MORE_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2( ... ) DBGC_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2_HDA( ... ) DBGC_HDA_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2_HD( ... ) DBGC_HD_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2_MD5A( ... ) DBGC_MD5A_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2_MD5( ... ) DBGC_MD5_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2_PAUSE( ... ) DBGC_PAUSE_IF ( EXTRA, ##__VA_ARGS__ ) #define DBGC2_MORE( ... ) DBGC_MORE_IF ( EXTRA, ##__VA_ARGS__ ) /* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( PROFILE, ... )*/ #define DBGP( ... ) DBG_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGP_HDA( ... ) DBG_HDA_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGP_HD( ... ) DBG_HD_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGP_MD5A( ... ) DBG_MD5A_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGP_MD5( ... ) DBG_MD5_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGP_PAUSE( ... ) DBG_PAUSE_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGP_MORE( ... ) DBG_MORE_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP( ... ) DBGC_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP_HDA( ... ) DBGC_HDA_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP_HD( ... ) DBGC_HD_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP_MD5A( ... ) DBGC_MD5A_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP_MD5( ... ) DBGC_MD5_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP_PAUSE( ... ) DBGC_PAUSE_IF ( PROFILE, ##__VA_ARGS__ ) #define DBGCP_MORE( ... ) DBGC_MORE_IF ( PROFILE, ##__VA_ARGS__ ) /* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( IO, ... )*/ #define DBGIO( ... ) DBG_IF ( IO, ##__VA_ARGS__ ) #define DBGIO_HDA( ... ) DBG_HDA_IF ( IO, ##__VA_ARGS__ ) #define DBGIO_HD( ... ) DBG_HD_IF ( IO, ##__VA_ARGS__ ) #define DBGIO_MD5A( ... ) DBG_MD5A_IF ( IO, ##__VA_ARGS__ ) #define DBGIO_MD5( ... ) DBG_MD5_IF ( IO, ##__VA_ARGS__ ) #define DBGIO_PAUSE( ... ) DBG_PAUSE_IF ( IO, ##__VA_ARGS__ ) #define DBGIO_MORE( ... ) DBG_MORE_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO( ... ) DBGC_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO_HDA( ... ) DBGC_HDA_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO_HD( ... ) DBGC_HD_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO_MD5A( ... ) DBGC_MD5A_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO_MD5( ... ) DBGC_MD5_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO_PAUSE( ... ) DBGC_PAUSE_IF ( IO, ##__VA_ARGS__ ) #define DBGCIO_MORE( ... ) DBGC_MORE_IF ( IO, ##__VA_ARGS__ ) #endif /* ASSEMBLY */ /** @} */ /** @defgroup attrs Miscellaneous attributes * @{ */ #ifndef ASSEMBLY /** Declare a variable or data structure as unused. */ #define __unused __attribute__ (( unused )) /** * Declare a function as pure - i.e. without side effects */ #define __pure __attribute__ (( pure )) /** * Declare a function as const - i.e. it does not access global memory * (including dereferencing pointers passed to it) at all. * Must also not call any non-const functions. */ #define __const __attribute__ (( const )) /** * Declare a function's pointer parameters as non-null - i.e. force * compiler to check pointers at compile time and enable possible * optimizations based on that fact */ #define __nonnull __attribute__ (( nonnull )) /** * Declare a pointer returned by a function as a unique memory address * as returned by malloc-type functions. */ #define __malloc __attribute__ (( malloc )) /** * Declare a function as used. * * Necessary only if the function is called only from assembler code. */ #define __used __attribute__ (( used )) /** Declare a data structure to be aligned with 16-byte alignment */ #define __aligned __attribute__ (( aligned ( 16 ) )) /** Declare a function to be always inline */ #define __always_inline __attribute__ (( always_inline )) /* Force all inline functions to not be instrumented * * This is required to cope with what seems to be a long-standing gcc * bug, in which -finstrument-functions will cause instances of * inlined functions to be reported as further calls to the * *containing* function. This makes instrumentation very difficult * to use. * * Work around this problem by adding the no_instrument_function * attribute to all inlined functions. */ #define inline inline __attribute__ (( no_instrument_function )) #endif /* ASSEMBLY */ /** @} */ /** * Optimisation barrier */ #ifndef ASSEMBLY #define barrier() __asm__ __volatile__ ( "" : : : "memory" ) #endif /* ASSEMBLY */ /** * Array size */ #ifndef ASSEMBLY #define ARRAY_SIZE(array) ( sizeof (array) / sizeof ( (array)[0] ) ) #endif /* ASSEMBLY */ /** @defgroup abs Absolute symbols * @{ */ #ifndef ASSEMBLY /** Declare an absolute symbol (e.g. a value defined by a linker script) * * Use as e.g.: * * extern int ABS_SYMBOL ( _my_symbol ); * */ #define ABS_SYMBOL( name ) name[] /** Get value of an absolute symbol for use in a static initializer * * Use as e.g.: * * extern int ABS_SYMBOL ( _my_symbol ); * static int my_symbol = ABS_VALUE_INIT ( _my_symbol ); * * Note that the declared type must be at least as large as a pointer * type, since the compiler sees the absolute symbol as being an * address. */ #define ABS_VALUE_INIT( name ) ( ( typeof ( name[0] ) ) name ) /** Get value of an absolute symbol * * In a position-dependent executable, where all addresses are fixed * at link time, we can use the standard technique as documented by * GNU ld, e.g.: * * extern char _my_symbol[]; * * printf ( "Absolute symbol value is %x\n", ( ( int ) _my_symbol ) ); * * This technique may not work in a position-independent executable. * When dynamic relocations are applied, the runtime addresses will no * longer be equal to the link-time addresses. If the code to obtain * the address of _my_symbol uses PC-relative addressing, then it * will calculate the runtime "address" of the absolute symbol, which * will no longer be equal the the link-time "address" (i.e. the * correct value) of the absolute symbol. * * We can work around this by instead declaring a static variable to * contain the absolute value, and returning the contents of this * static variable: * * extern char _my_symbol[]; * static void * volatile my_symbol = _my_symbol; * * printf ( "Absolute symbol value is %x\n", ( ( int ) my_symbol ) ); * * The value of the static variable cannot possibly use PC-relative * addressing (since there is no applicable program counter for * non-code), and so will instead be filled in with the correct * absolute value at link time. (No dynamic relocation will be * generated that might change its value, since the symbol providing * the value is an absolute symbol.) * * This second technique will work for both position-dependent and * position-independent code, but incurs the unnecssary overhead of an * additional static variable in position-dependent code. The * ABS_VALUE() macro abstracts away these differences, using the most * efficient available technique. Use as e.g.: * * extern int ABS_SYMBOL ( _my_symbol ); * #define my_symbol ABS_VALUE ( _my_symbol ) * * printf ( "Absolute symbol value is %x\n", my_symbol ); * * The ABS_VALUE() macro uses the (otherwise redundant) type declared * on the ABS_SYMBOL() array to automatically determine the correct * type for the ABS_VALUE() expression. * * Unlike ABS_VALUE_INIT(), there is no restriction that the type must * be at least as large as a pointer type. */ #ifndef __pie__ #define ABS_VALUE( name ) ( ( typeof ( name[0] ) ) ( intptr_t ) name ) #else #define ABS_VALUE( name ) ( { \ static void * volatile static_ ## name = name; \ ( ( typeof ( name[0] ) ) ( intptr_t ) static_ ## name ); \ } ) #endif #endif /* ASSEMBLY */ /** @} */ /** * @defgroup licences Licence declarations * * For reasons that are partly historical, various different files * within the iPXE codebase have differing licences. * * @{ */ /** Declare a file as being in the public domain * * This licence declaration is applicable when a file states itself to * be in the public domain. */ #define FILE_LICENCE_PUBLIC_DOMAIN \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__public_domain__ ) ) /** Declare a file as being under version 2 (or later) of the GNU GPL * * This licence declaration is applicable when a file states itself to * be licensed under the GNU GPL; "either version 2 of the License, or * (at your option) any later version". */ #define FILE_LICENCE_GPL2_OR_LATER \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__gpl2_or_later__ ) ) /** Declare a file as being under version 2 of the GNU GPL * * This licence declaration is applicable when a file states itself to * be licensed under version 2 of the GPL, and does not include the * "or, at your option, any later version" clause. */ #define FILE_LICENCE_GPL2_ONLY \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__gpl2_only__ ) ) /** Declare a file as being under any version of the GNU GPL * * This licence declaration is applicable when a file states itself to * be licensed under the GPL, but does not specify a version. * * According to section 9 of the GPLv2, "If the Program does not * specify a version number of this License, you may choose any * version ever published by the Free Software Foundation". */ #define FILE_LICENCE_GPL_ANY \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__gpl_any__ ) ) /** Declare a file as being under the three-clause BSD licence * * This licence declaration is applicable when a file states itself to * be licensed under terms allowing redistribution in source and * binary forms (with or without modification) provided that: * * redistributions of source code retain the copyright notice, * list of conditions and any attached disclaimers * * redistributions in binary form reproduce the copyright notice, * list of conditions and any attached disclaimers in the * documentation and/or other materials provided with the * distribution * * the name of the author is not used to endorse or promote * products derived from the software without specific prior * written permission * * It is not necessary for the file to explicitly state that it is * under a "BSD" licence; only that the licensing terms be * functionally equivalent to the standard three-clause BSD licence. */ #define FILE_LICENCE_BSD3 \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__bsd3__ ) ) /** Declare a file as being under the two-clause BSD licence * * This licence declaration is applicable when a file states itself to * be licensed under terms allowing redistribution in source and * binary forms (with or without modification) provided that: * * redistributions of source code retain the copyright notice, * list of conditions and any attached disclaimers * * redistributions in binary form reproduce the copyright notice, * list of conditions and any attached disclaimers in the * documentation and/or other materials provided with the * distribution * * It is not necessary for the file to explicitly state that it is * under a "BSD" licence; only that the licensing terms be * functionally equivalent to the standard two-clause BSD licence. */ #define FILE_LICENCE_BSD2 \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__bsd2__ ) ) /** Declare a file as being under the two-clause BSD plus patent licence * * This licence declaration is applicable when a file states itself to * be licensed under terms allowing redistribution in source and * binary forms (with or without modification) provided that: * * redistributions of source code retain the copyright notice, * list of conditions and any attached disclaimers * * redistributions in binary form reproduce the copyright notice, * list of conditions and any attached disclaimers in the * documentation and/or other materials provided with the * distribution * * and in addition states that * * Subject to the terms and conditions of this license, each * copyright holder and contributor hereby grants to those * receiving rights under this license a perpetual, worldwide, * non-exclusive, no-charge, royalty-free, irrevocable (except for * failure to satisfy the conditions of this license) patent * license to make, have made, use, offer to sell, sell, import, * and otherwise transfer this software, where such license * applies only to those patent claims, already acquired or * hereafter acquired, licensable by such copyright holder or * contributor that are necessarily infringed by: * * their Contribution(s) (the licensed copyrights of copyright * holders and non-copyrightable additions of contributors, in * source or binary form) alone; or * * combination of their Contribution(s) with the work of * authorship to which such Contribution(s) was added by such * copyright holder or contributor, if, at the time the * Contribution is added, such addition causes such combination * to be necessarily infringed. The patent license shall not * apply to any other combinations which include the * Contribution. * * It is not necessary for the file to explicitly state that it is * under a "BSD" licence; only that the licensing terms be * functionally equivalent to the standard two-clause BSD licence with * patent grant. */ #define FILE_LICENCE_BSD2_PATENT \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__bsd2_patent__ ) ) /** Declare a file as being under the one-clause MIT-style licence * * This licence declaration is applicable when a file states itself to * be licensed under terms allowing redistribution for any purpose * with or without fee, provided that the copyright notice and * permission notice appear in all copies. */ #define FILE_LICENCE_MIT \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__mit__ ) ) /** Declare a file as being under GPLv2+ or UBDL * * This licence declaration is applicable when a file states itself to * be licensed under the GNU GPL; "either version 2 of the License, or * (at your option) any later version" and also states that it may be * distributed under the terms of the Unmodified Binary Distribution * Licence (as given in the file COPYING.UBDL). */ #define FILE_LICENCE_GPL2_OR_LATER_OR_UBDL \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __licence__gpl2_or_later_or_ubdl__ ) ) /** Declare a particular licence as applying to a file */ #define FILE_LICENCE( _licence ) FILE_LICENCE_ ## _licence /** @} */ /* This file itself is under GPLv2+/UBDL */ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); /** * @defgroup secboot UEFI Secure Boot restrictions * * Not all files within the iPXE codebase are allowed to be included * in UEFI Secure Boot signed builds. * * Files that are permitted in a UEFI Secure Boot build are subject to * stricter code review requirements. In particular, contributions * from third parties may not be marked as permitted unless they have * passed an approved security review. * * @{ */ /** Declare a file as being permitted in a UEFI Secure Boot build */ #define FILE_SECBOOT_PERMITTED \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __secboot__permitted__ ) ) /** Declare a file as being forbidden in a UEFI Secure Boot build */ #define FILE_SECBOOT_FORBIDDEN \ PROVIDE_SYMBOL ( PREFIX_OBJECT ( __secboot__forbidden__ ) ) /** Declare a file's UEFI Secure Boot permission status */ #define FILE_SECBOOT( _status ) FILE_SECBOOT_ ## _status /** @} */ /* This file itself is permitted in a Secure Boot build */ FILE_SECBOOT ( PERMITTED ); #include <bits/compiler.h> #endif /* COMPILER_H */