arch/x86/kernel/static_call.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/static_call.h>
   3 #include <linux/memory.h>
   4 #include <linux/bug.h>
   5 #include <asm/text-patching.h>
   6
   7 static void __static_call_transform(void *insn, u8 opcode, void *func)
   8 {
   9         const void *code = text_gen_insn(opcode, insn, func);
  10
  11         if (WARN_ONCE(*(u8 *)insn != opcode,
  12                       "unexpected static call insn opcode 0x%x at %pS\n",
  13                       opcode, insn))
  14                 return;
  15
  16         if (memcmp(insn, code, CALL_INSN_SIZE) == 0)
  17                 return;
  18
  19         text_poke_bp(insn, code, CALL_INSN_SIZE, NULL);
  20 }
  21
  22 void arch_static_call_transform(void *site, void *tramp, void *func)
  23 {
  24         mutex_lock(&text_mutex);
  25
  26         if (tramp)
  27                 __static_call_transform(tramp, JMP32_INSN_OPCODE, func);
  28
  29         mutex_unlock(&text_mutex);
  30 }
  31 EXPORT_SYMBOL_GPL(arch_static_call_transform);