[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 02/10] x86: assembly, FUNC_START for fn, DATA_START for data
On 03/22/2017, 03:11 PM, Josh Poimboeuf wrote: > Or, here's a much easier way to do it, without involving objtool: > > --- a/include/linux/linkage.h > +++ b/include/linux/linkage.h > @@ -138,9 +138,17 @@ > name: > #endif > > +#ifndef CHECK_DUP_SYM_END > +#define CHECK_DUP_SYM_END(name) \ > + .pushsection .discard.sym_func_end ASM_NL \ > + SYM_END_##name: .byte 0 ASM_NL \ > + .popsection > +#endif > + > /* SYM_END -- use only if you have to */ > #ifndef SYM_END > #define SYM_END(name, sym_type) \ > + CHECK_DUP_SYM_END(name) ASM_NL \ > .type name sym_type ASM_NL \ > .size name, .-name > #endif I tried this approach and it didn't work for me inside .macros. Oh, well, the name cannot be first, so now, we can have a check for both correct pairing _and_ duplicate ends in one: #define SYM_CHECK_START(name) \ .pushsection .rodata.bubak ASM_NL \ .long has_no_SYM_END_##name - . ASM_NL \ .popsection #define SYM_CHECK_END(name) \ has_no_SYM_END_##name: /* SYM_START -- use only if you have to */ #ifndef SYM_START #define SYM_START(name, align, visibility, entry) \ SYM_CHECK_START(name) ASM_NL \ visibility(name) ASM_NL \ align ASM_NL \ name: ASM_NL \ entry #endif /* SYM_END -- use only if you have to */ #ifndef SYM_END #define SYM_END(name, sym_type, exit) \ exit ASM_NL \ SYM_CHECK_END(name) ASM_NL \ .type name sym_type ASM_NL \ .size name, .-name #endif So for the ftrace mistake I did: AS arch/x86/kernel/mcount_64.o /home/latest/linux/arch/x86/kernel/mcount_64.S: Assembler messages: /home/latest/linux/arch/x86/kernel/mcount_64.S:192: Error: symbol `has_no_SYM_END_ftrace_caller' is already defined or if I remove SYM_END_FUNC completely: LD vmlinux.o MODPOST vmlinux.o arch/x86/built-in.o:(.rodata.bubak+0x130): undefined reference to `has_no_SYM_END_ftrace_stub' Sad is that this occurs only during linking, so I cannot put it in the .discard section -- ideas? thanks, -- js suse labs _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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