[0/2] firewire: obsolete cast of function callback toward CFI

Message

Takashi Sakamoto May 20, 2020, 6:47 a.m. UTC

Hi,

Oscar Carter works for Control Flow Integrity build. Any cast
of function callback is inconvenient for the work. Unfortunately,
current code of firewire-core driver includes the cast[1] and Oscar
posted some patches to remove it[2]. The patch is itself good. However,
it includes changes existent kernel API and all of drivers as user
of the API get affects from the change.

This patchset is an alternative idea to add a new kernel API specific
for multichannel isoc context. The existent kernel API and drivers is
left as is.

Practically, no in-kernel drivers use the additional API. Although the
API is exported in the patchset, it's better to discuss about unexporting
the API.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/firewire/core-cdev.c#n985
[2] https://lore.kernel.org/lkml/[e-mail]/

Regards

Takashi Sakamoto (2):
  firewire-core: add kernel API to construct multichannel isoc context
  firewire-core: obsolete cast of function callback

 drivers/firewire/core-cdev.c | 44 +++++++++++++++++++-----------------
 drivers/firewire/core-iso.c  | 17 ++++++++++++++
 include/linux/firewire.h     |  3 +++
 3 files changed, 43 insertions(+), 21 deletions(-)

Comments

Oscar Carter May 22, 2020, 5:35 p.m. UTC | #1

Hi,

On Wed, May 20, 2020 at 03:47:24PM +0900, Takashi Sakamoto wrote:
> Hi,
>
> Oscar Carter works for Control Flow Integrity build. Any cast
> of function callback is inconvenient for the work. Unfortunately,
> current code of firewire-core driver includes the cast[1] and Oscar
> posted some patches to remove it[2]. The patch is itself good. However,
> it includes changes existent kernel API and all of drivers as user
> of the API get affects from the change.
>
> This patchset is an alternative idea to add a new kernel API specific
> for multichannel isoc context. The existent kernel API and drivers is
> left as is.
>
> Practically, no in-kernel drivers use the additional API. Although the
> API is exported in the patchset, it's better to discuss about unexporting
> the API.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/firewire/core-cdev.c#n985
> [2] https://lore.kernel.org/lkml/[e-mail]/
>
> Regards
>
> Takashi Sakamoto (2):
>   firewire-core: add kernel API to construct multichannel isoc context
>   firewire-core: obsolete cast of function callback
>
>  drivers/firewire/core-cdev.c | 44 +++++++++++++++++++-----------------
>  drivers/firewire/core-iso.c  | 17 ++++++++++++++
>  include/linux/firewire.h     |  3 +++
>  3 files changed, 43 insertions(+), 21 deletions(-)
>
> --
> 2.25.1
>
Thanks for your work and new proposal. I've done a test build an it cleans the
-Wcast-function-type warning without the need to change the current API. So, it
looks good to me.

Thanks,
Oscar Carter