On Tue, Dec 15, 2020, Uros Bizjak wrote: > This patch series introduces try_cmpxchg64() atomic locking function. > > try_cmpxchg64() provides the same interface for 64 bit and 32 bit targets, > emits CMPXCHGQ for 64 bit targets and CMPXCHG8B for 32 bit targets, > and provides appropriate fallbacks when CMPXCHG8B is unavailable. > > try_cmpxchg64() reuses flags from CMPXCHGQ/CMPXCHG8B instructions and > avoids unneeded CMP for 64 bit targets or XOR/XOR/OR sequence for > 32 bit targets. > > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Boqun Feng <boqun.feng@xxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxxxx> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Sean Christopherson <seanjc@xxxxxxxxxx> > Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx> > Cc: Jim Mattson <jmattson@xxxxxxxxxx> > Cc: Joerg Roedel <joro@xxxxxxxxxx> > > Uros Bizjak (3): > asm-generic/atomic: Add try_cmpxchg64() instrumentation > locking/atomic/x86: Introduce arch_try_cmpxchg64() > KVM/VMX: Use try_cmpxchg64() in posted_intr.c For anyone else trying to apply this, it depends on v5.11-rc1 (commit 29f006fdefe6, "asm-generic/atomic: Add try_cmpxchg() fallbacks"), which hasn't yet been merged into Paolo's tree. > arch/x86/include/asm/cmpxchg_32.h | 62 +++++++++++++++++++---- > arch/x86/include/asm/cmpxchg_64.h | 6 +++ > arch/x86/kvm/vmx/posted_intr.c | 9 ++-- > include/asm-generic/atomic-instrumented.h | 46 ++++++++++++++++- > scripts/atomic/gen-atomic-instrumented.sh | 2 +- > 5 files changed, 108 insertions(+), 17 deletions(-) > > -- > 2.26.2 >
