PERF_REG_ARM64_X21   27 arch/arm64/include/uapi/asm/perf_regs.h 	PERF_REG_ARM64_X21,
PERF_REG_ARM64_X21   27 tools/arch/arm64/include/uapi/asm/perf_regs.h 	PERF_REG_ARM64_X21,