Remember the Verbosity (A Brief Note)

Tuesday 17 April 2007 by Bradley M. Kuhn

I don't remember when it happened, but sometime in the past four years, the Makefiles for the kernel named Linux changed. I can't remember exactly, but I do recall sometime “recently” that the kernel build output stopped looking like what I remember from 1991, and started looking like this:

CC arch/i386/kernel/semaphore.o
CC arch/i386/kernel/signal.o

This is a heck of a lot easier to read, but there was something cool about having make display the whole gcc command lines, like this:

gcc -m32 -Wp,-MD,arch/i386/kernel/.semaphore.o.d -nostdinc -isystem /usr/lib/gcc/i486-linux-gnu/4.0.3/include -D__KERNEL__ -Iinclude -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -Os -fomit-frame-pointer -pipe -msoft-float -mpreferred-stack-boundary=2 -march=i686 -mtune=pentium4 -Iinclude/asm-i386/mach-default -Wdeclaration-after-statement -Wno-pointer-sign -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(semaphore)" -D"KBUILD_MODNAME=KBUILD_STR(semaphore)" -c -o arch/i386/kernel/semaphore.o arch/i386/kernel/semaphore.c
gcc -m32 -Wp,-MD,arch/i386/kernel/.signal.o.d -nostdinc -isystem /usr/lib/gcc/i486-linux-gnu/4.0.3/include -D__KERNEL__ -Iinclude -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -Os -fomit-frame-pointer -pipe -msoft-float -mpreferred-stack-boundary=2 -march=i686 -mtune=pentium4 -Iinclude/asm-i386/mach-default -Wdeclaration-after-statement -Wno-pointer-sign -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(signal)" -D"KBUILD_MODNAME=KBUILD_STR(signal)" -c -o arch/i386/kernel/signal.o arch/i386/kernel/signal.c

I never gave it much thought, since the new form was easier to read. I figured that those folks who still eat kernel code for breakfast knew about this change well ahead of time. Of course, they were the only ones who needed to see the verbose output of the gcc command lines. I could live with seeing the simpler CC lines for my purposes, until today.

I was compiling kernel code and for the first time since this change in the Makefiles, I was using a non-default gcc to build Linux. I wanted to double-check that I'd given the right options to make throughout the process. I therefore found myself looking for a way to see the full output again (and for the first time). It was easy enough to figure out: giving the variable setting V=1 to make gives you the verbose version. For you Debian folks like me, we're using make-kpkg, so the line we need looks like: MAKEFLAGS="V=1" make-kpkg kernel_image.

It's nice sometimes to pretend I'm compiling 0.99pl12 again and not :) No matter which options you give make, it is still a whole lot easier to bootstrap Linux these days.

Posted on Tuesday 17 April 2007 at 17:56 by Bradley M. Kuhn.

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