On Mon, May 22, 2017 at 4:34 AM, Jiri Kosina <jikos@xxxxxxxxxx> wrote: > On Sat, 20 May 2017, H.J. Lu wrote: > >> >>>> pushq %whatever >> >>>> .cfi_adjust_sp -8 >> >>>> ... >> >>>> popq %whatever >> >>>> .cfi_adjust_sp 8 >> >>>> >> >> >> >> Np. Compiler needs to generate this. >> >> >> > >> > How would the compiler generate this when inline asm is involved? For >> > the kernel, objtool could get around the need to have these >> > annotations, but not so much for user code? Is the compiler supposed >> > to parse the inline asm? Would the compiler provide some magic % code >> > to represent the current CFA base register? >> >> Here is one example of inline asm with call frame info: >> >> https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/x86_64/sigaction.c;h=be058bac436d1cc9794b2b03107676ed99f6b872;hb=HEAD > > That brings us basically pretty close to square one though; having to > maintain "manual" anotations. Something we're pretty much trying to avoid > through this excercise. Assembler only encodes instructions. You need to a different tool to figure out what an instruction does. -- H.J. -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
