----- On Feb 6, 2018, at 11:51 AM, efficios efficios@xxxxxxxxxxxxxxxxxxx wrote:
> Ensure we gather architecture requirements about each architecture supporting
> the "sync_core" membarrier command in a single file under
> Documentation/features.
>
> [ This patch applies on top of tip sched/core. ]
please disregard this email. I will fix my git config on this dev machine and
re-send.
Thanks,
Mathieu
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Cc: Andrea Parri <parri.andrea@xxxxxxxxx>
> Cc: Andrew Hunter <ahh@xxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxx>
> Cc: Avi Kivity <avi@xxxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
> Cc: Dave Watson <davejwatson@xxxxxx>
> Cc: David Sehr <sehr@xxxxxxxxxx>
> Cc: Greg Hackmann <ghackmann@xxxxxxxxxx>
> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Maged Michael <maged.michael@xxxxxxxxx>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: linux-api@xxxxxxxxxxxxxxx
> Cc: linux-arch@xxxxxxxxxxxxxxx
> ---
> .../sched/membarrier-sync-core/arch-support.txt | 62 ++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
> create mode 100644
> Documentation/features/sched/membarrier-sync-core/arch-support.txt
>
> diff --git a/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> new file mode 100644
> index 0000000..2c815a7
> --- /dev/null
> +++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt
> @@ -0,0 +1,62 @@
> +#
> +# Feature name: membarrier-sync-core
> +# Kconfig: ARCH_HAS_MEMBARRIER_SYNC_CORE
> +# description: arch supports core serializing membarrier
> +#
> +# Architecture requirements
> +#
> +# * arm64
> +#
> +# Rely on eret context synchronization when returning from IPI handler, and
> +# when returning to user-space.
> +#
> +# * x86
> +#
> +# x86-32 uses IRET as return from interrupt, which takes care of the IPI.
> +# However, it uses both IRET and SYSEXIT to go back to user-space. The IRET
> +# instruction is core serializing, but not SYSEXIT.
> +#
> +# x86-64 uses IRET as return from interrupt, which takes care of the IPI.
> +# However, it can return to user-space through either SYSRETL (compat code),
> +# SYSRETQ, or IRET.
> +#
> +# Given that neither SYSRET{L,Q}, nor SYSEXIT, are core serializing, we rely
> +# instead on write_cr3() performed by switch_mm() to provide core serialization
> +# after changing the current mm, and deal with the special case of kthread ->
> +# uthread (temporarily keeping current mm into active_mm) by issuing a
> +# sync_core_before_usermode() in that specific case.
> +#
> + -----------------------
> + | arch |status|
> + -----------------------
> + | alpha: | TODO |
> + | arc: | TODO |
> + | arm: | TODO |
> + | arm64: | ok |
> + | blackfin: | TODO |
> + | c6x: | TODO |
> + | cris: | TODO |
> + | frv: | TODO |
> + | h8300: | TODO |
> + | hexagon: | TODO |
> + | ia64: | TODO |
> + | m32r: | TODO |
> + | m68k: | TODO |
> + | metag: | TODO |
> + | microblaze: | TODO |
> + | mips: | TODO |
> + | mn10300: | TODO |
> + | nios2: | TODO |
> + | openrisc: | TODO |
> + | parisc: | TODO |
> + | powerpc: | TODO |
> + | s390: | TODO |
> + | score: | TODO |
> + | sh: | TODO |
> + | sparc: | TODO |
> + | tile: | TODO |
> + | um: | TODO |
> + | unicore32: | TODO |
> + | x86: | ok |
> + | xtensa: | TODO |
> + -----------------------
> --
> 1.9.1
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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