From: Jiang Liu <jiang....@huawei.com> This patchset tries to optimize arch specfic jump label implementation for ARM64 by dynamic kernel text patching.
To enable this feature, your toolchain must support "asm goto" extension and "%c" constraint extesion. Current GCC for AARCH64 doesn't support "%c", so you need a GCC patch similiar to this: http://gcc.gnu.org/viewcvs/gcc/trunk/gcc/config/arm/arm.c?view=patch&r1=175293&r2=175565&pathrev=175565 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637 It has been tested on ARM Fast mode and a real hardware platform. Any comments are welcomed! V3->V4: 1) resolve a race condition in kernel text patching 2) address other review comments V2->V3: 1) fix a bug in comparing signed and unsigned values 2) detect big endian by checking __AARCH64EB__ V1->V2: address review comments of V1 1) refine comments 2) add a new interface to always synchronize with stop_machine() when patching code 3) handle endian issue when patching code Jiang Liu (7): arm64: introduce basic aarch64 instruction decoding helpers arm64: introduce interfaces to hotpatch kernel and module code arm64: move encode_insn_immediate() from module.c to insn.c arm64: introduce aarch64_insn_gen_{nop|branch_imm}() helper functions arm64, jump label: detect %c support for ARM64 arm64, jump label: optimize jump label implementation jump_label: use defined macros instead of hard-coding for better readability arch/arm64/Kconfig | 1 + arch/arm64/include/asm/insn.h | 110 +++++++++++++++++ arch/arm64/include/asm/jump_label.h | 52 ++++++++ arch/arm64/kernel/Makefile | 3 +- arch/arm64/kernel/insn.c | 235 ++++++++++++++++++++++++++++++++++++ arch/arm64/kernel/jump_label.c | 58 +++++++++ arch/arm64/kernel/module.c | 152 +++++++---------------- include/linux/jump_label.h | 15 ++- scripts/gcc-goto.sh | 2 +- 9 files changed, 514 insertions(+), 114 deletions(-) create mode 100644 arch/arm64/include/asm/insn.h create mode 100644 arch/arm64/include/asm/jump_label.h create mode 100644 arch/arm64/kernel/insn.c create mode 100644 arch/arm64/kernel/jump_label.c -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
