apply_alternatives

函数名称：Replace instructions with better alternatives for this CPU type. This runs* before SMP is initialized to avoid SMP problems with self modifying code.* This implies that asymmetric systems where APs have less capabilities than

函数原型：void __init_or_module noinline apply_alternatives(struct alt_instr *start, struct alt_instr *end)

返回类型：void

参数：

类型	参数	名称
struct alt_instr *	start
struct alt_instr *	end

388

insn_buff_sz等于0

390

instr = (u8 * ) & original instruction + original instruction

391

replacement = (u8 * ) & offset to replacement instruction + offset to replacement instruction

392

BUG_ON( length of original instruction > insn_buff的长度)

393

BUG_ON( cpuid bit set for replacement >= (N 32-bit words worth of info + N 32-bit bug flags ) * 32)

394

如果非boot_cpu_has( cpuid bit set for replacement )则

395

如果 length of build-time padding 大于1则"noinline" to cause control flow change and thus invalidate I$ and* cause refetch after modification.

398

继续下一循环

401

DPRINTK("feat: %d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d), pad: %d", cpuid bit set for replacement >> 5, cpuid bit set for replacement & 0x1f, instr, instr, length of original instruction , replacement, length of new instruction , length of build-time padding )

407

DUMP_BYTES(instr, length of original instruction , "%px: old_insn: ", instr)

408

DUMP_BYTES(replacement, length of new instruction , "%px: rpl_insn: ", replacement)

410

memcpy(insn_buff, replacement, length of new instruction )

411

insn_buff_sz等于 length of new instruction

419

如果 length of new instruction 恒等于5且insn_buff恒等于0xe8则

420

*insn_buff加1的和加等于replacement减instr

421

DPRINTK("Fix CALL offset: 0x%x, CALL 0x%lx", * (s32 * )(insn_buff + 1), (unsignedlong)instr + * (s32 * )(insn_buff + 1) + 5)

426

如果 length of new instruction 且Are we looking at a near JMP with a 1 or 4-byte displacement.则recompute_jump(a, instr, replacement, insn_buff)

429

如果 length of original instruction 大于 length of new instruction 则

430

Use this to add nops to a buffer, then text_poke the whole buffer.

432

insn_buff_sz加等于 length of original instruction 减 length of new instruction

434

DUMP_BYTES(insn_buff, insn_buff_sz, "%px: final_insn: ", instr)

436

xt_poke_early - Update instructions on a live kernel at boot time*@addr: address to modify*@opcode: source of the copy*@len: length to copy* When you use this code to patch more than one byte of an instruction

名称	描述
alternative_instructions
arch_klp_init_object_loaded	Apply per-object alternatives. Based on x86 module_finalize()
module_finalize

函数逻辑报告