[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 01/10] linkage: new macros for assembler symbols
Introduce new C macros for annotations of functions and data in assembly. There is a long-term mess in macros like ENTRY, END, ENDPROC and similar. They are used in different manners and sometimes incorrectly. So introduce macros with clear use to annotate assembly as follows: a) Support macros SYM_T_FUNC -- type used by assembler to mark functions SYM_T_OBJECT -- type used by assembler to mark data They are defined as STT_FUNC and STT_OBJECT respectively. According to the gas manual, this is the most portable way. I am not sure about other assemblers, so we can switch this back to %function and %object if this turns into a problem. Architectures can also override them by something like ", @function" if need be. SYM_A_ALIGN, SYM_A_NOALIGN -- should we align the symbol? SYM_V_GLOBAL, SYM_V_WEAK, SYM_V_LOCAL -- visibility of symbols b) Mostly internal annotations, used by the ones below SYM_START -- use only if you have to SYM_END -- use only if you have to c) Generic annotations d) Annotations for code SYM_FUNC_START_LOCAL_ALIAS -- use where there are two local names for one code SYM_FUNC_START_ALIAS -- use where there are two global names for one code SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed code SYM_FUNC_START -- use for global functions SYM_FUNC_START_LOCAL -- use for local functions SYM_FUNC_START_WEAK -- use for weak functions SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START, SYM_FUNC_START_WEAK, ... SYM_FUNC_INNER_LABEL -- only for global labels in the middle of functions d) For data SYM_DATA_START -- global data symbol SYM_DATA_END -- the end of SYM_DATA_START symbol ========== Note that SYM_FUNC_START_WEAK aligns symbols now too. The macros allow to pair starts and ends of functions and mark function correctly in the output ELF objects. This will also help a lot to generate DWARF information automatically during build of asm. Finally, all users of the old macros will be converted to use these later. [v2] * use SYM_ prefix and sane names * add SYM_START and SYM_END and parametrize all the macros Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: hpa@xxxxxxxxx Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: jpoimboe@xxxxxxxxxx Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Len Brown <len.brown@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: linux-pm@xxxxxxxxxxxxxxx Cc: mingo@xxxxxxxxxx Cc: Pavel Machek <pavel@xxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx Cc: x86@xxxxxxxxxx --- arch/x86/include/asm/linkage.h | 5 +- include/linux/linkage.h | 131 ++++++++++++++++++++++++++++++++++++++--- 2 files changed, 126 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 0ccb26dda126..a96f6fc36011 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -12,9 +12,8 @@ #ifdef __ASSEMBLY__ -#define GLOBAL(name) \ - .globl name; \ - name: +/* deprecated, use SYM_DATA_START, SYM_FUNC_START, or SYM_FUNC_INNER_LABEL */ +#define GLOBAL(name) SYM_DATA_START(name) #if defined(CONFIG_X86_64) || defined(CONFIG_X86_ALIGNMENT_16) #define __ALIGN .p2align 4, 0x90 diff --git a/include/linux/linkage.h b/include/linux/linkage.h index a6a42dd02466..c1dc824d2bc6 100644 --- a/include/linux/linkage.h +++ b/include/linux/linkage.h @@ -74,25 +74,46 @@ #ifdef __ASSEMBLY__ +/* SYM_T_FUNC -- type used by assembler to mark functions */ +#ifndef SYM_T_FUNC +#define SYM_T_FUNC STT_FUNC +#endif + +/* SYM_T_OBJECT -- type used by assembler to mark data */ +#ifndef SYM_T_OBJECT +#define SYM_T_OBJECT STT_OBJECT +#endif + +/* SYM_A_* -- should we align the symbol? */ +#define SYM_A_ALIGN ALIGN +#define SYM_A_NOALIGN /* nothing */ + +/* SYM_V_* -- visibility of symbols */ +#define SYM_V_GLOBAL(name) .globl name +#define SYM_V_WEAK(name) .weak name +#define SYM_V_LOCAL(name) /* nothing */ + #ifndef LINKER_SCRIPT #define ALIGN __ALIGN #define ALIGN_STR __ALIGN_STR +/* === DEPRECATED annotations === */ + #ifndef ENTRY +/* deprecated, use SYM_FUNC_START */ #define ENTRY(name) \ - .globl name ASM_NL \ - ALIGN ASM_NL \ - name: + SYM_FUNC_START(name) #endif #endif /* LINKER_SCRIPT */ #ifndef WEAK +/* deprecated, use SYM_FUNC_START_WEAK */ #define WEAK(name) \ - .weak name ASM_NL \ - name: + SYM_FUNC_START_WEAK(name) #endif #ifndef END +/* deprecated, use SYM_FUNC_END, SYM_DATA_END, or SYM_END */ #define END(name) \ .size name, .-name #endif @@ -102,9 +123,105 @@ * static analysis tools such as stack depth analyzer. */ #ifndef ENDPROC +/* deprecated, use SYM_FUNC_END */ #define ENDPROC(name) \ - .type name, @function ASM_NL \ - END(name) + SYM_FUNC_END(name) +#endif + +/* === generic annotations === */ + +/* SYM_START -- use only if you have to */ +#ifndef SYM_START +#define SYM_START(name, align, visibility) \ + visibility(name) ASM_NL \ + align ASM_NL \ + name: +#endif + +/* SYM_END -- use only if you have to */ +#ifndef SYM_END +#define SYM_END(name, sym_type) \ + .type name sym_type ASM_NL \ + .size name, .-name +#endif + +/* === code annotations === */ + +/* SYM_FUNC_START_LOCAL_ALIAS -- use where there are two local names for one code */ +#ifndef SYM_FUNC_START_LOCAL_ALIAS +#define SYM_FUNC_START_LOCAL_ALIAS(name) \ + SYM_START(name, SYM_A_ALIGN, SYM_V_LOCAL) +#endif + +/* SYM_FUNC_START_ALIAS -- use where there are two global names for one code */ +#ifndef SYM_FUNC_START_ALIAS +#define SYM_FUNC_START_ALIAS(name) \ + SYM_START(name, SYM_A_ALIGN, SYM_V_GLOBAL) +#endif + +/* SYM_FUNC_START -- use for global functions */ +#ifndef SYM_FUNC_START +/* + * The same as SYM_FUNC_START_ALIAS, but we will need to distinguish these two + * later. + */ +#define SYM_FUNC_START(name) \ + SYM_START(name, SYM_A_ALIGN, SYM_V_GLOBAL) +#endif + +/* SYM_FUNC_START_LOCAL -- use for local functions */ +#ifndef SYM_FUNC_START_LOCAL +/* the same as SYM_FUNC_START_LOCAL_ALIAS, see comment near SYM_FUNC_START */ +#define SYM_FUNC_START_LOCAL(name) \ + SYM_START(name, SYM_A_ALIGN, SYM_V_LOCAL) +#endif + +/* SYM_FUNC_START_WEAK -- use for weak functions */ +#ifndef SYM_FUNC_START_WEAK +#define SYM_FUNC_START_WEAK(name) \ + SYM_START(name, SYM_A_ALIGN, SYM_V_WEAK) +#endif + +/* SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed code */ +#ifndef SYM_FUNC_END_ALIAS +#define SYM_FUNC_END_ALIAS(name) \ + SYM_END(name, SYM_T_FUNC) +#endif + +/* + * SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START, + * SYM_FUNC_START_WEAK, ... + */ +#ifndef SYM_FUNC_END +/* the same as SYM_FUNC_END_ALIAS, see comment near SYM_FUNC_START */ +#define SYM_FUNC_END(name) \ + SYM_END(name, SYM_T_FUNC) +#endif + +/* SYM_FUNC_INNER_LABEL -- only for global labels to the middle of functions */ +#ifndef SYM_FUNC_INNER_LABEL +#define SYM_FUNC_INNER_LABEL(name) \ + SYM_START(name, SYM_A_NOALIGN, SYM_V_GLOBAL) +#endif + +/* === data annotations === */ + +/* SYM_DATA_START -- global data symbol */ +#ifndef SYM_DATA_START +#define SYM_DATA_START(name) \ + SYM_START(name, SYM_A_NOALIGN, SYM_V_GLOBAL) +#endif + +/* SYM_DATA_START -- local data symbol */ +#ifndef SYM_DATA_START_LOCAL +#define SYM_DATA_START_LOCAL(name) \ + SYM_START(name, SYM_A_NOALIGN, SYM_V_LOCAL) +#endif + +/* SYM_DATA_END -- the end of SYM_DATA_START symbol */ +#ifndef SYM_DATA_END +#define SYM_DATA_END(name) \ + SYM_END(name, SYM_T_OBJECT) #endif #endif -- 2.12.0 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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