[PATCH 00/12] kbuild: enable some -Wextra warnings by default

[PATCH 00/12] kbuild: enable some -Wextra warnings by default

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

This is a follow-up on a couple of patch series I sent in the past,
enabling -Wextra (aside from stuff that is explicitly disabled),
-Wcast-function-pointer-strict and -Wrestrict.

I have tested these on 'defconfig' and 'allmodconfig' builds across
all architectures, as well as many 'randconfig' builds on x86, arm and
arm64. It would be nice to have all the Makefile.extrawarn changes in
v6.10, hopefully with the driver fixes going in before that through
the respective subsystem trees.

     Arnd

Arnd Bergmann (12):
  kbuild: make -Woverride-init warnings more consistent
  [v3] parport: mfc3: avoid empty-body warning
  kbuild: turn on -Wextra by default
  kbuild: remove redundant extra warning flags
  firmware: dmi-id: add a release callback function
  nouveau: fix function cast warning
  cxlflash: fix function pointer cast warnings
  x86: math-emu: fix function cast warnings
  kbuild: enable -Wcast-function-type-strict unconditionally
  sata: sx4: fix pdc20621_get_from_dimm() on 64-bit
  [v4] kallsyms: rework symbol lookup return codes
  kbuild: turn on -Wrestrict by default

 arch/x86/math-emu/fpu_etc.c                   |  9 +++--
 arch/x86/math-emu/fpu_trig.c                  |  6 ++--
 arch/x86/math-emu/reg_constant.c              |  7 +++-
 drivers/ata/sata_sx4.c                        |  6 ++--
 drivers/firmware/dmi-id.c                     |  7 +++-
 .../gpu/drm/amd/display/dc/dce110/Makefile    |  2 +-
 .../gpu/drm/amd/display/dc/dce112/Makefile    |  2 +-
 .../gpu/drm/amd/display/dc/dce120/Makefile    |  2 +-
 drivers/gpu/drm/amd/display/dc/dce60/Makefile |  2 +-
 drivers/gpu/drm/amd/display/dc/dce80/Makefile |  2 +-
 drivers/gpu/drm/i915/Makefile                 |  6 ++--
 .../drm/nouveau/nvkm/subdev/bios/shadowof.c   |  7 +++-
 drivers/gpu/drm/xe/Makefile                   |  4 +--
 drivers/net/ethernet/renesas/sh_eth.c         |  2 +-
 drivers/parport/parport_mfc3.c                |  3 +-
 drivers/pinctrl/aspeed/Makefile               |  2 +-
 drivers/scsi/cxlflash/lunmgt.c                |  4 +--
 drivers/scsi/cxlflash/main.c                  | 14 ++++----
 drivers/scsi/cxlflash/superpipe.c             | 34 +++++++++----------
 drivers/scsi/cxlflash/superpipe.h             | 11 +++---
 drivers/scsi/cxlflash/vlun.c                  |  7 ++--
 fs/proc/Makefile                              |  2 +-
 include/linux/filter.h                        | 14 ++++----
 include/linux/ftrace.h                        |  6 ++--
 include/linux/module.h                        | 14 ++++----
 kernel/bpf/Makefile                           |  2 +-
 kernel/bpf/core.c                             |  7 ++--
 kernel/kallsyms.c                             | 23 +++++++------
 kernel/module/kallsyms.c                      | 26 +++++++-------
 kernel/trace/ftrace.c                         | 13 +++----
 mm/Makefile                                   |  3 +-
 scripts/Makefile.extrawarn                    | 33 ++++--------------
 32 files changed, 134 insertions(+), 148 deletions(-)

-- 
2.39.2

Cc: Bill Metzenthen <billm@melbpc.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Sergey Shtylyov <s.shtylyov@omp.ru>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Andrew Jeffery <andrew@codeconstruct.com.au>
Cc: "Manoj N. Kumar" <manoj@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-ide@vger.kernel.org
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: intel-xe@lists.freedesktop.org
Cc: netdev@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-scsi@vger.kernel.org
Cc: bpf@vger.kernel.org
Cc: linux-trace-kernel@vger.kernel.org
Cc: linux-modules@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kbuild@vger.kernel.org
Cc: llvm@lists.linux.dev

[PATCH 06/12] nouveau: fix function cast warning

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

Calling a function through an incompatible pointer type causes breaks
kcfi, so clang warns about the assignment:

drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c:73:10: error: cast from 'void (*)(const void *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
   73 |         .fini = (void(*)(void *))kfree,

Avoid this with a trivial wrapper.

Fixes: c39f472e9f14 ("drm/nouveau: remove symlinks, move core/ to nvkm/ (no code changes)")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
index 4bf486b57101..0dbcc23305f3 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
@@ -66,11 +66,16 @@ of_init(struct nvkm_bios *bios, const char *name)
 	return ERR_PTR(-EINVAL);
 }
 
+static void of_fini(void *p)
+{
+	return kfree(p);
+}
+
 const struct nvbios_source
 nvbios_of = {
 	.name = "OpenFirmware",
 	.init = of_init,
-	.fini = (void(*)(void *))kfree,
+	.fini = of_fini,
 	.read = of_read,
 	.size = of_size,
 	.rw = false,
-- 
2.39.2

Re: [PATCH 06/12] nouveau: fix function cast warning

[Timur Tabi]

On Tue, 2024-03-26 at 15:51 +0100, Arnd Bergmann wrote:
> Calling a function through an incompatible pointer type causes breaks
> kcfi, so clang warns about the assignment:
> 

...

> +static void of_fini(void *p)
> +{
> +       return kfree(p);
> +}
> +

I don't know anything about kfci, but shouldn't this just be "kfree(p)",
without the "return"?

Re: [PATCH 06/12] nouveau: fix function cast warning

[Arnd Bergmann]

On Tue, Mar 26, 2024, at 16:20, Timur Tabi wrote:
> On Tue, 2024-03-26 at 15:51 +0100, Arnd Bergmann wrote:
>> Calling a function through an incompatible pointer type causes breaks
>> kcfi, so clang warns about the assignment:
>> 
>
> ...
>
>> +static void of_fini(void *p)
>> +{
>> +       return kfree(p);
>> +}
>> +
>
> I don't know anything about kfci, but shouldn't this just be "kfree(p)",
> without the "return"?

You are right, fixed this up locally now, waiting for more
comments before I resend patches from my series.

I think it works because of a gcc extension, but isn't
valid C otherwise, and I did not mean to rely on this.

     Arnd