path: root/Documentation/index.rst
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authorJiri Slaby <>2019-10-11 13:50:41 +0200
committerBorislav Petkov <>2019-10-18 09:48:11 +0200
commitffedeeb780dc554eff3d3b16e6a462a26a41d7ec (patch)
treea50a13e5062acdef7d29725b871cdac10c0e9fb9 /Documentation/index.rst
parent30a2441cae7b149ff484a697bf9eb8de53240a4f (diff)
linkage: Introduce new macros for assembler symbols
Introduce new C macros for annotations of functions and data in assembly. There is a long-standing 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 for the ones below SYM_T_FUNC -- type used by assembler to mark functions SYM_T_OBJECT -- type used by assembler to mark data SYM_T_NONE -- type used by assembler to mark entries of unknown type They are defined as STT_FUNC, STT_OBJECT, and STT_NOTYPE respectively. According to the gas manual, this is the most portable way. I am not sure about other assemblers, so this can be switched back to %function and %object if this turns into a problem. Architectures can also override them by something like ", @function" if they need. SYM_A_ALIGN, SYM_A_NONE -- align the symbol? SYM_L_GLOBAL, SYM_L_WEAK, SYM_L_LOCAL -- linkage of symbols b) Mostly internal annotations, used by the ones below SYM_ENTRY -- use only if you have to (for non-paired symbols) SYM_START -- use only if you have to (for paired symbols) SYM_END -- use only if you have to (for paired symbols) c) Annotations for code SYM_INNER_LABEL_ALIGN -- only for labels in the middle of code SYM_INNER_LABEL -- only for labels in the middle of code SYM_FUNC_START_LOCAL_ALIAS -- use where there are two local names for one function SYM_FUNC_START_ALIAS -- use where there are two global names for one function SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed function SYM_FUNC_START -- use for global functions SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment SYM_FUNC_START_LOCAL -- use for local functions SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment SYM_FUNC_START_WEAK -- use for weak functions SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START, SYM_FUNC_START_WEAK, ... For functions with special (non-C) calling conventions: SYM_CODE_START -- use for non-C (special) functions SYM_CODE_START_NOALIGN -- use for non-C (special) functions, w/o alignment SYM_CODE_START_LOCAL -- use for local non-C (special) functions SYM_CODE_START_LOCAL_NOALIGN -- use for local non-C (special) functions, w/o alignment SYM_CODE_END -- the end of SYM_CODE_START_LOCAL or SYM_CODE_START d) For data SYM_DATA_START -- global data symbol SYM_DATA_START_LOCAL -- local data symbol SYM_DATA_END -- the end of the SYM_DATA_START symbol SYM_DATA_END_LABEL -- the labeled end of SYM_DATA_START symbol SYM_DATA -- start+end wrapper around simple global data SYM_DATA_LOCAL -- start+end wrapper around simple local data ========== The macros allow to pair starts and ends of functions and mark functions correctly in the output ELF objects. All users of the old macros in x86 are converted to use these in further patches. Signed-off-by: Jiri Slaby <> Signed-off-by: Borislav Petkov <> Acked-by: Rafael J. Wysocki <> Cc: Andrew Morton <> Cc: Andrey Ryabinin <> Cc: Boris Ostrovsky <> Cc: "H. Peter Anvin" <> Cc: Ingo Molnar <> Cc: Jonathan Corbet <> Cc: Josh Poimboeuf <> Cc: Juergen Gross <> Cc: Len Brown <> Cc: Linus Torvalds <> Cc: Cc: Cc: Cc: Cc: Mark Rutland <> Cc: Pavel Machek <> Cc: Peter Zijlstra <> Cc: Thomas Gleixner <> Cc: Will Deacon <> Cc: x86-ml <> Cc: Link:
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diff --git a/Documentation/index.rst b/Documentation/index.rst
index b843e313d2f2..2ceab197246f 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -135,6 +135,14 @@ needed).
+Architecture-agnostic documentation
+.. toctree::
+ :maxdepth: 2
+ asm-annotations
Architecture-specific documentation