* architectures that still need to remove set_fs()
@ 2022-01-18 7:48 Christoph Hellwig
2022-01-18 11:48 ` Stafford Horne
0 siblings, 1 reply; 2+ messages in thread
From: Christoph Hellwig @ 2022-01-18 7:48 UTC (permalink / raw)
To: Richard Henderson, Ivan Kokshaysky, Matt Turner, Vineet Gupta,
Guo Ren, Brian Cain, Michal Simek, Nick Hu, Greentime Hu,
Vincent Chen, Dinh Nguyen, Jonas Bonn, Stefan Kristiansson,
Stafford Horne, Yoshinori Sato, Rich Felker, David S. Miller,
Chris Zankel, Max Filippov
Cc: linux-alpha, linux-snps-arc, linux-csky, linux-hexagon,
linux-ia64, openrisc, linux-sh, sparclinux, linux-xtensa,
linux-arch, linux-kernel
Hi all,
you are in this list because your architecture still implements and
uses address space overrides using set_fs(), which are deprecated and
have been removed from all mainstream architecture ports. To help
cleanup the core kernel it would be great to make progress on removing
set_fs entirely.
The following steps are required:
(1) implement the __get_kernel_nofault and __put_kernel_nofault
helper to access kernel memory without page faults, replacing
the get/put_user under set_fs(KERNEL_DS) abuse. Mips has a good
example for a trivial implementation for architectures that use
a common address space in commit 04324f44cb69
(2) remove any architecture specific use of such constructs. This
only affects ia64 and sh.
(3) stop selecting the SET_FS and remove all the set_fs-related
infrastructure. The above mips commit is a good guide once again.
Thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: architectures that still need to remove set_fs()
2022-01-18 7:48 architectures that still need to remove set_fs() Christoph Hellwig
@ 2022-01-18 11:48 ` Stafford Horne
0 siblings, 0 replies; 2+ messages in thread
From: Stafford Horne @ 2022-01-18 11:48 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Richard Henderson, Ivan Kokshaysky, Matt Turner, Vineet Gupta,
Guo Ren, Brian Cain, Michal Simek, Nick Hu, Greentime Hu,
Vincent Chen, Dinh Nguyen, Jonas Bonn, Stefan Kristiansson,
Yoshinori Sato, Rich Felker, David S. Miller, Chris Zankel,
Max Filippov, linux-alpha, linux-snps-arc, linux-csky,
linux-hexagon, linux-ia64, openrisc, linux-sh, sparclinux,
linux-xtensa, linux-arch, linux-kernel
Hi,
On Tue, Jan 18, 2022 at 08:48:36AM +0100, Christoph Hellwig wrote:
> Hi all,
>
> you are in this list because your architecture still implements and
> uses address space overrides using set_fs(), which are deprecated and
> have been removed from all mainstream architecture ports. To help
> cleanup the core kernel it would be great to make progress on removing
> set_fs entirely.
>
> The following steps are required:
>
> (1) implement the __get_kernel_nofault and __put_kernel_nofault
> helper to access kernel memory without page faults, replacing
> the get/put_user under set_fs(KERNEL_DS) abuse. Mips has a good
> example for a trivial implementation for architectures that use
> a common address space in commit 04324f44cb69
Also see commit 08ee3a009f49a which is preparation for removing set_fs/get_fs
this commit implements __get_kernel_nofault/__put_kernel_nofault for mips.
> (2) remove any architecture specific use of such constructs. This
> only affects ia64 and sh.
> (3) stop selecting the SET_FS and remove all the set_fs-related
> infrastructure. The above mips commit is a good guide once again.
>
> Thanks!
I will look into this for OpenRISC.
-Stafford
^ permalink raw reply [flat|nested] 2+ messages in thread
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