Le 06/11/2020 à 16:59, Nicholas Piggin a écrit :
This series attempts to improve the speed of interrupts and system calls
in two major ways.
Firstly, the SRR/HSRR registers do not need to be reloaded if they were
not used or clobbered fur the duration of the interrupt.
Secondly, an alternate 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
executes no mtsprs and one mtmsrd to enable interrupts initially, and
the system call vectored path doesn't even need to do that.
Interesting series.
Unfortunately, can't be done on PPC32 (at least on non bookE), because it would mean mapping kernel
at 0 instead of 0xC0000000. Not sure libc would like it, and anyway it would be an issue for
catching NULL pointer dereferencing, unless we use page tables instead of BATs to map kernel mem,
which would be serious performance cut.
Christophe
Thanks,
Nick
Nicholas Piggin (9):
powerpc/64s: syscall real mode entry use mtmsrd rather than rfid
powerpc/64s: system call avoid setting MSR[RI] until we set MSR[EE]
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: move interrupt return asm to interrupt_64.S
powerpc/64s: save one more register in the masked interrupt handler
powerpc/64s: allow alternate return locations for soft-masked
interrupts
powerpc/64s: interrupt soft-enable race fix
powerpc/64s: use interrupt restart table to speed up return from
interrupt
arch/powerpc/Kconfig.debug | 5 +
arch/powerpc/include/asm/asm-prototypes.h | 4 +-
arch/powerpc/include/asm/head-64.h | 2 +-
arch/powerpc/include/asm/interrupt.h | 18 +
arch/powerpc/include/asm/paca.h | 3 +
arch/powerpc/include/asm/ppc_asm.h | 8 +
arch/powerpc/include/asm/ptrace.h | 28 +-
arch/powerpc/kernel/asm-offsets.c | 5 +
arch/powerpc/kernel/entry_64.S | 508 ---------------
arch/powerpc/kernel/exceptions-64s.S | 180 ++++--
arch/powerpc/kernel/fpu.S | 2 +
arch/powerpc/kernel/head_64.S | 5 +-
arch/powerpc/kernel/interrupt_64.S | 720 +++++++++++++++++++++
arch/powerpc/kernel/irq.c | 79 ++-
arch/powerpc/kernel/kgdb.c | 2 +-
arch/powerpc/kernel/kprobes-ftrace.c | 2 +-
arch/powerpc/kernel/kprobes.c | 10 +-
arch/powerpc/kernel/process.c | 21 +-
arch/powerpc/kernel/rtas.c | 13 +-
arch/powerpc/kernel/signal.c | 2 +-
arch/powerpc/kernel/signal_64.c | 14 +
arch/powerpc/kernel/syscall_64.c | 242 ++++---
arch/powerpc/kernel/syscalls.c | 2 +
arch/powerpc/kernel/traps.c | 18 +-
arch/powerpc/kernel/vector.S | 6 +-
arch/powerpc/kernel/vmlinux.lds.S | 10 +
arch/powerpc/lib/Makefile | 2 +-
arch/powerpc/lib/restart_table.c | 26 +
arch/powerpc/lib/sstep.c | 5 +-
arch/powerpc/math-emu/math.c | 2 +-
arch/powerpc/mm/fault.c | 2 +-
arch/powerpc/perf/core-book3s.c | 19 +-
arch/powerpc/platforms/powernv/opal-call.c | 3 +
arch/powerpc/sysdev/fsl_pci.c | 2 +-
34 files changed, 1244 insertions(+), 726 deletions(-)
create mode 100644 arch/powerpc/kernel/interrupt_64.S
create mode 100644 arch/powerpc/lib/restart_table.c
