[0/4] CPUCFG emulation on older Loongson64 cores

Message

WANG Xuerui May 2, 2020, 1:38 p.m. UTC

This patch series brings the CPUCFG instruction to older Loongson64
cores, enabling a unified way to query processor characteristics on
Loongson64 systems. A detailed explanation may be found in the last
commit.

One unresolved point is how to best introduce machtype-specific bits
into the generic MIPS code, namely the cpu probing and trap handler
parts. I have been struggling over whether to lift this logic into
arch/mips/kernel, but the instruction's encoding (reusing LWC2 opcode)
might be too invasive to be useful to other MIPS platforms. What do
people think is the best way forward?

WANG Xuerui (4):
  MIPS: Loongson64: fix typos in loongson_regs.h
  MIPS: Loongson64: define offsets and known revisions for some CPUCFG
    features
  MIPS: define more Loongson CP0.Config6 and CP0.Diag feature bits
  MIPS: emulate CPUCFG instruction on older Loongson64 cores

 arch/mips/Kconfig                             |  11 ++
 arch/mips/include/asm/cpu-info.h              |   9 ++
 .../include/asm/mach-loongson64/cpucfg-emul.h |  67 +++++++++
 .../asm/mach-loongson64/loongson_regs.h       |  27 +++-
 arch/mips/include/asm/mipsregs.h              |   6 +
 arch/mips/kernel/cpu-probe.c                  | 129 ++++++++++++++++++
 arch/mips/kernel/traps.c                      |  57 ++++++++
 arch/mips/loongson64/Makefile                 |   1 +
 arch/mips/loongson64/cpucfg-emul.c            |  80 +++++++++++
 9 files changed, 383 insertions(+), 4 deletions(-)
 create mode 100644 arch/mips/include/asm/mach-loongson64/cpucfg-emul.h
 create mode 100644 arch/mips/loongson64/cpucfg-emul.c