This makes r14 a fixed register and used to store per-cpu stuff in the kernel, including read-write fields that are retained over interrupts. It ends up being most useful for speeding up per-cpu pointer dereferencing and soft-irq masking and testing. But it can also reduce the number of loads and stores in the interrupt entry paths by moving several bits of interest into r14 (another bit I'm looking at is adding a bit for HSTATE_IN_GUEST to speed up kvmtest).
The series goes on top of Maddy's softi-irq patches, it works on 64s, but KVM and 64e are probably broken at the moment. So it's not intended to merge yet, but if people like the result then maybe the first patch can be merged to stop using r14 in preparation. Nicholas Piggin (8): powerpc/64s: stop using r14 register powerpc/64s: poison r14 register while in kernel powerpc/64s: put the per-cpu data_offset in r14 powerpc/64s: put io_sync bit into r14 powerpc/64s: put work_pending bit into r14 powerpc/64s: put irq_soft_mask bits into r14 powerpc/64s: put irq_soft_mask and irq_happened bits into r14 powerpc/64s: inline local_irq_enable/restore arch/powerpc/Makefile | 1 + arch/powerpc/crypto/md5-asm.S | 40 +++---- arch/powerpc/crypto/sha1-powerpc-asm.S | 10 +- arch/powerpc/include/asm/exception-64s.h | 127 +++++++++++---------- arch/powerpc/include/asm/hw_irq.h | 130 ++++++++++----------- arch/powerpc/include/asm/io.h | 11 +- arch/powerpc/include/asm/irqflags.h | 24 ++-- arch/powerpc/include/asm/kvm_book3s_asm.h | 2 +- arch/powerpc/include/asm/kvm_ppc.h | 6 +- arch/powerpc/include/asm/paca.h | 73 +++++++++++- arch/powerpc/include/asm/percpu.h | 2 +- arch/powerpc/include/asm/ppc_asm.h | 21 +++- arch/powerpc/include/asm/spinlock.h | 21 ++-- arch/powerpc/kernel/asm-offsets.c | 23 +++- arch/powerpc/kernel/entry_32.S | 4 +- arch/powerpc/kernel/entry_64.S | 95 ++++++++++------ arch/powerpc/kernel/exceptions-64s.S | 52 ++++----- arch/powerpc/kernel/head_64.S | 25 ++-- arch/powerpc/kernel/idle_book3s.S | 86 +++++++------- arch/powerpc/kernel/irq.c | 92 ++++++--------- arch/powerpc/kernel/kgdb.c | 8 +- arch/powerpc/kernel/optprobes_head.S | 3 +- arch/powerpc/kernel/paca.c | 1 - arch/powerpc/kernel/process.c | 6 +- arch/powerpc/kernel/setup_64.c | 19 +++- arch/powerpc/kernel/time.c | 15 +-- arch/powerpc/kernel/tm.S | 40 ++++--- arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 10 +- arch/powerpc/kvm/book3s_hv.c | 6 +- arch/powerpc/kvm/book3s_hv_interrupts.S | 5 +- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 3 +- arch/powerpc/kvm/book3s_interrupts.S | 93 +++++++++++---- arch/powerpc/kvm/book3s_pr.c | 6 + arch/powerpc/lib/checksum_64.S | 66 +++++------ arch/powerpc/lib/copypage_power7.S | 32 +++--- arch/powerpc/lib/copyuser_power7.S | 152 ++++++++++++------------- arch/powerpc/lib/crtsavres.S | 3 + arch/powerpc/lib/memcpy_power7.S | 80 ++++++------- arch/powerpc/lib/sstep.c | 1 + arch/powerpc/xmon/xmon.c | 7 +- 40 files changed, 764 insertions(+), 637 deletions(-) -- 2.15.0
