Commit-ID: 6a546c7e69ff0b69581377cc70d7e8a601b98fce Gitweb: https://git.kernel.org/tip/6a546c7e69ff0b69581377cc70d7e8a601b98fce Author: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> AuthorDate: Fri, 9 Feb 2018 15:30:56 -0500 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Sat, 10 Feb 2018 12:45:10 +0100
membarrier-sync-core: Document architecture support Ensure we gather architecture requirements about each architecture supporting the "sync_core" membarrier command in a single file under Documentation/features. Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> Cc: Andrea Parri <parri.and...@gmail.com> Cc: Andrew Hunter <a...@google.com> Cc: Andy Lutomirski <l...@kernel.org> Cc: Avi Kivity <a...@scylladb.com> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> Cc: Boqun Feng <boqun.f...@gmail.com> Cc: Dave Watson <davejwat...@fb.com> Cc: David Sehr <s...@google.com> Cc: Greg Hackmann <ghackm...@google.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Maged Michael <maged.mich...@gmail.com> Cc: Michael Ellerman <m...@ellerman.id.au> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Russell King <li...@armlinux.org.uk> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Will Deacon <will.dea...@arm.com> Cc: linux-...@vger.kernel.org Cc: linux-a...@vger.kernel.org Link: http://lkml.kernel.org/r/1518208256-22034-1-git-send-email-mathieu.desnoy...@efficios.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- .../sched/membarrier-sync-core/arch-support.txt | 62 ++++++++++++++++++++++ 1 file changed, 62 insertions(+) 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 | + -----------------------
