This series attempts to improve the speed of interrupts and system calls in three major ways.
Firstly, the SRR/HSRR registers do not need to be reloaded if they were clobbered for the duration of the interrupt and the return NIP and MSR did not changed. 64e does not implement this part, but it could quite easily. Secondly, mtmsrd and mtspr are reduced by various means, this is mostly specific to 64s. Lastly, an alternate interrupt return location facility is added for soft-masked asynchronous interrupts, and then that's used to set everything up for return without having to disable MSR RI or EE. After this series, the entire system call / interrupt handler fast path can execute with no mtsprs and one mtmsrd to enable interrupts initially, and the system call vectored path doesn't even need to do that. This gives a decent performance benefit. On POWER9 with a powernv_defconfig without VIRT_CPU_ACCOUNTING_NATIVE, no meltdown workarounds, gettid sc system call goes from 481 -> 344 cycles, gettid scv 345->299 cycles, and page fault 1225->1064 cycles. Since v3: - Added Christophe's series to the end (with one broken out patch at the start and minor tweaks). - Fix lbz of SOFTE that broke on BE, should be loaded with ld. - Fix case where fast_interrupt_return was not marking SRRs as clobbered correctly, causing random userspace segfaults etc. - Fix cpu lock inversion problem in the workaround static branch switching code. - Removed the .L local name from some labels for the restart handlers, which makes the disassembly easier to read. - Fixed several nitpicks found by kbuild robot (duplicate include, missing prototypes, etc). - Fix 64e compile bug [from mpe]. - Fix KUAP re-locking in some restart cases. Christophe Leroy (6): powerpc/interrupt: Fix CONFIG ifdef typo powerpc/interrupt: Rename and lightly change syscall_exit_prepare_main() powerpc/interrupt: Refactor interrupt_exit_user_prepare() powerpc/interrupt: Interchange prep_irq_for_{kernel_enabled/user}_exit() powerpc/interrupt: Refactor prep_irq_for_{user/kernel_enabled}_exit() powerpc/interrupt: Remove prep_irq_for_user_exit() Nicholas Piggin (11): powerpc: remove interrupt exit helpers unused argument powerpc/64s: introduce different functions to return from SRR vs HSRR interrupts powerpc/64s: avoid reloading (H)SRR registers if they are still valid powerpc/64: handle MSR EE and RI in interrupt entry wrapper powerpc/64: move interrupt return asm to interrupt_64.S powerpc/64s: system call avoid setting MSR[RI] until we set MSR[EE] powerpc/64s: save one more register in the masked interrupt handler powerpc/64: allow alternate return locations for soft-masked interrupts powerpc/64: interrupt soft-enable race fix powerpc/64: treat low kernel text as irqs soft-masked powerpc/64: use interrupt restart table to speed up return from interrupt arch/powerpc/Kconfig.debug | 5 + arch/powerpc/include/asm/asm-prototypes.h | 9 +- arch/powerpc/include/asm/head-64.h | 2 +- arch/powerpc/include/asm/hw_irq.h | 23 +- arch/powerpc/include/asm/interrupt.h | 60 +- arch/powerpc/include/asm/paca.h | 7 + arch/powerpc/include/asm/ppc_asm.h | 8 + arch/powerpc/include/asm/ptrace.h | 75 ++- arch/powerpc/kernel/asm-offsets.c | 7 + arch/powerpc/kernel/entry_64.S | 516 -------------- arch/powerpc/kernel/exceptions-64e.S | 53 +- arch/powerpc/kernel/exceptions-64s.S | 219 +++--- arch/powerpc/kernel/fpu.S | 4 + arch/powerpc/kernel/head_64.S | 5 +- arch/powerpc/kernel/interrupt.c | 413 +++++++----- arch/powerpc/kernel/interrupt_64.S | 742 +++++++++++++++++++++ arch/powerpc/kernel/irq.c | 95 +++ arch/powerpc/kernel/kgdb.c | 2 +- arch/powerpc/kernel/kprobes-ftrace.c | 2 +- arch/powerpc/kernel/kprobes.c | 10 +- arch/powerpc/kernel/process.c | 26 +- arch/powerpc/kernel/prom_init.c | 3 + arch/powerpc/kernel/rtas.c | 14 +- arch/powerpc/kernel/signal.c | 2 +- arch/powerpc/kernel/signal_64.c | 9 + arch/powerpc/kernel/syscalls.c | 3 +- arch/powerpc/kernel/traps.c | 18 +- arch/powerpc/kernel/vector.S | 8 +- arch/powerpc/kernel/vmlinux.lds.S | 10 + arch/powerpc/kvm/book3s_hv.c | 3 + arch/powerpc/kvm/book3s_pr.c | 2 + arch/powerpc/lib/Makefile | 2 +- arch/powerpc/lib/feature-fixups.c | 52 +- arch/powerpc/lib/restart_table.c | 30 + arch/powerpc/lib/sstep.c | 4 +- arch/powerpc/math-emu/math.c | 2 +- arch/powerpc/platforms/powernv/opal-call.c | 4 + arch/powerpc/platforms/pseries/hvCall.S | 29 + arch/powerpc/sysdev/fsl_pci.c | 2 +- 39 files changed, 1622 insertions(+), 858 deletions(-) create mode 100644 arch/powerpc/kernel/interrupt_64.S create mode 100644 arch/powerpc/lib/restart_table.c -- 2.23.0