Re: [PATCH v5 -next 14/16] sh: vdso: move the sysctl to arch/sh/kernel/vsyscall/vsyscall.c

On 1/11/25 01:07, Kaixiong Yu wrote:
> When CONFIG_SUPERH and CONFIG_VSYSCALL are defined,
> vdso_enabled belongs to arch/sh/kernel/vsyscall/vsyscall.c.
> So, move it into its own file. To avoid failure when registering
> the vdso_table, move the call to register_sysctl_init() into
> its own fs_initcall().
> 
> Signed-off-by: Kaixiong Yu <[email protected]>
> Reviewed-by: Kees Cook <[email protected]>
> ---
> v5:
>   - fix the error discovered by Geert Uytterhoeven.
>     Move the call to register_sysctl_init() into
>     its own fs_initcall() as Geert Uytterhoeven's patch does.
>   - take the advice of Joel Granados, separating path14 in V4
>     into patch14 and patch15 in V5. This patch just moves the
>     vdso_enabled table. The next patch removes the vm_table.
>   - modify the change log

Speaking of, what would it take to add gettimeofday() and 
clock_gettime() vdso functions on superh? I looked into it a few weeks 
ago but found the subsystem hard to parse.

Rob

P.S. On j-core we have three memory mapped registers any process can 
read, the rtc_nsec, rtc_seclo, and rtc_sechi fields in the AIC structure 
at 
https://github.com/j-core/jcore-soc/blob/master/targets/boards/turtle_1v1/board.h#L29 
(volatile unsigned *hlc = (void *)0xabcd0220, or just x = *(volatile 
unsigned *)0xabcd0228; if you're checking before/after nanoseconds for 
quick and dirty profiling), which has let us be really lazy but ideally 
there would be a proper vdso wrapper, and the with-mmu version is going 
to want a little more kernel participation...