arch/powerpc/kernel/static_call.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/memory.h>
   3 #include <linux/static_call.h>
   4
   5 #include <asm/code-patching.h>
   6
   7 void arch_static_call_transform(void *site, void *tramp, void *func, bool tail)
   8 {
   9         int err;
  10         bool is_ret0 = (func == __static_call_return0);
  11         unsigned long target = (unsigned long)(is_ret0 ? tramp + PPC_SCT_RET0 : func);
  12         bool is_short = is_offset_in_branch_range((long)target - (long)tramp);
  13
  14         if (!tramp)
  15                 return;
  16
  17         mutex_lock(&text_mutex);
  18
  19         if (func && !is_short) {
  20                 err = patch_instruction(tramp + PPC_SCT_DATA, ppc_inst(target));
  21                 if (err)
  22                         goto out;
  23         }
  24
  25         if (!func)
  26                 err = patch_instruction(tramp, ppc_inst(PPC_RAW_BLR()));
  27         else if (is_short)
  28                 err = patch_branch(tramp, target, 0);
  29         else
  30                 err = patch_instruction(tramp, ppc_inst(PPC_RAW_NOP()));
  31 out:
  32         mutex_unlock(&text_mutex);
  33
  34         if (err)
  35                 panic("%s: patching failed %pS at %pS\n", __func__, func, tramp);
  36 }
  37 EXPORT_SYMBOL_GPL(arch_static_call_transform);