Messages in this thread | | | From | Jisheng Zhang <> | Subject | [PATCH 0/3] unified way to use static key and optimize pgtable_l4_enabled | Date | Wed, 26 Jan 2022 00:50:33 +0800 |
| |
Currently, riscv has several features why may not be supported on all riscv platforms, for example, FPU, SV48 and so on. To support unified kernel Image style, we need to check whether the feature is suportted or not. If the check sits at hot code path, then performance will be impacted a lot. static key can be used to solve the issue. In the past FPU support has been converted to use static key mechanism. I believe we will have similar cases in the future. For example, the SV48 support can take advantage of static key[1].
patch1 introduces an unified mechanism to use static key for riscv cpu features. patch2 converts has_cpu() to use the mechanism. patch3 uses the mechanism to optimize pgtable_l4_enabled.
[1] http://lists.infradead.org/pipermail/linux-riscv/2021-December/011164.html
Jisheng Zhang (3): riscv: introduce unified static key mechanism for CPU features riscv: replace has_fpu() with system_supports_fpu() riscv: convert pgtable_l4_enabled to static key
arch/riscv/Makefile | 3 + arch/riscv/include/asm/cpufeature.h | 105 ++++++++++++++++++++++++++++ arch/riscv/include/asm/pgalloc.h | 8 +-- arch/riscv/include/asm/pgtable-64.h | 21 +++--- arch/riscv/include/asm/pgtable.h | 3 +- arch/riscv/include/asm/switch_to.h | 9 +-- arch/riscv/kernel/cpu.c | 2 +- arch/riscv/kernel/cpufeature.c | 29 ++++++-- arch/riscv/kernel/process.c | 2 +- arch/riscv/kernel/signal.c | 4 +- arch/riscv/mm/init.c | 23 +++--- arch/riscv/mm/kasan_init.c | 6 +- arch/riscv/tools/Makefile | 22 ++++++ arch/riscv/tools/cpucaps | 6 ++ arch/riscv/tools/gen-cpucaps.awk | 40 +++++++++++ 15 files changed, 234 insertions(+), 49 deletions(-) create mode 100644 arch/riscv/include/asm/cpufeature.h create mode 100644 arch/riscv/tools/Makefile create mode 100644 arch/riscv/tools/cpucaps create mode 100755 arch/riscv/tools/gen-cpucaps.awk
-- 2.34.1
| |