From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- .../sched/membarrier-sync-core/arch-support.txt | 54 ++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 Documentation/features/sched/membarrier-sync-core/arch-support.txt (limited to '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 0000000000..23260ca449 --- /dev/null +++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt @@ -0,0 +1,54 @@ +# +# Feature name: membarrier-sync-core +# Kconfig: ARCH_HAS_MEMBARRIER_SYNC_CORE +# description: arch supports core serializing membarrier +# +# Architecture requirements +# +# * arm/arm64/powerpc/s390 +# +# Rely on implicit context synchronization as a result of exception return +# 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: | ok | + | arm64: | ok | + | csky: | TODO | + | hexagon: | TODO | + | ia64: | TODO | + | loongarch: | TODO | + | m68k: | TODO | + | microblaze: | TODO | + | mips: | TODO | + | nios2: | TODO | + | openrisc: | TODO | + | parisc: | TODO | + | powerpc: | ok | + | riscv: | TODO | + | s390: | ok | + | sh: | TODO | + | sparc: | TODO | + | um: | TODO | + | x86: | ok | + | xtensa: | TODO | + ----------------------- -- cgit v1.2.3