Messages in this thread | | | From | Max Filippov <> | Date | Fri, 16 Mar 2018 11:12:09 -0700 | Subject | Re: arc_usr_cmpxchg and preemption |
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> On Thu, Mar 15, 2018 at 12:03 PM, Alexey Brodkin <Alexey.Brodkin@synopsys.com> wrote: > Here's a brief analysis: > ARM: Looks like they got rid of that stuff in v4.4, see > commit db695c0509d6 ("ARM: remove user cmpxchg syscall"). > > M68K: That's even uglier implementation which is really asking for > a facelift, look at sys_atomic_cmpxchg_32() here: > https://elixir.bootlin.com/linux/latest/source/arch/m68k/kernel/sys_m68k.c#L461 > > MIPS: They do it via special sysmips syscall which among other things > might handle MIPS_ATOMIC_SET with mips_atomic_set() > > I don't immediately see if there're others but really I'm not sure if it even worth trying to > clean-up all that since efforts might be spent pointlessly.
xtensa is another one. We used to have a buggy implementation in arch/xtensa/kernel/entry.S:fast_syscall_xtensa which we still keep disabled by default, just in case somebody wanted backwards compatibility. I don't think it's worth fixing.
-- Thanks. -- Max
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