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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date: Sun, 24 Mar 2024 19:14:38 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: Uros Bizjak <ubizjak@gmail.com>, linux-kernel@vger.kernel.org,
	x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	David.Laight@aculab.com,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v4 00/16] x86-64: Stack protector and percpu improvements
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* Brian Gerst <brgerst@gmail.com> wrote:

> > > But, "make oldconfig" will still silently disable stack protector if 
> > > the compiler doesn't support the new options.  It does put the 
> > > comment into the .config file though, so that may be enough.
> >
> > So I was thinking more along the lines of emitting an actual warning to 
> > the build log, every time the compiler check is executed and fails to 
> > detect [certain] essential or good-to-have compiler features.
> >
> > A bit like the red '[ OFF ]' build lines during the perf build:
> >
> > Auto-detecting system features:
> >
> > ...                                   dwarf: [ on  ]
> > ...                      dwarf_getlocations: [ on  ]
> > ...                                   glibc: [ on  ]
> > ...                                  libbfd: [ on  ]
> > ...                          libbfd-buildid: [ on  ]
> > ...                                  libcap: [ on  ]
> > ...                                  libelf: [ on  ]
> > ...                                 libnuma: [ on  ]
> > ...                  numa_num_possible_cpus: [ on  ]
> > ...                                 libperl: [ on  ]
> > ...                               libpython: [ on  ]
> > ...                               libcrypto: [ on  ]
> > ...                               libunwind: [ on  ]
> > ...                      libdw-dwarf-unwind: [ on  ]
> > ...                             libcapstone: [ OFF ]  <========
> > ...                                    zlib: [ on  ]
> > ...                                    lzma: [ on  ]
> > ...                               get_cpuid: [ on  ]
> > ...                                     bpf: [ on  ]
> > ...                                  libaio: [ on  ]
> > ...                                 libzstd: [ on  ]
> >
> > ... or something like that.
> >
> > Thanks,
> >
> >         Ingo
> 
> That list comes from the perf tool itself
> (tools/perf/builtin-version.c), not the kernel config or build system.

Yeah, I know, I wrote the initial version. ;-)

( See upstream commits b6aa9979416e~1..4cc9117a35b2 )

> Something like that could be added to the main kernel build.  But it 
> should be a separate patch series as it will likely need a lot of design 
> iteration.

Doesn't have to be complicated really, but obviously not a requirement for 
this series.

Thanks,

	Ingo