arch/s390/kernel/rethook.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 #include <linux/rethook.h>
   3 #include <linux/kprobes.h>
   4 #include "rethook.h"
   5
   6 void arch_rethook_prepare(struct rethook_node *rh, struct pt_regs *regs, bool mcount)
   7 {
   8         rh->ret_addr = regs->gprs[14];
   9         rh->frame = regs->gprs[15];
  10
  11         /* Replace the return addr with trampoline addr */
  12         regs->gprs[14] = (unsigned long)&arch_rethook_trampoline;
  13 }
  14 NOKPROBE_SYMBOL(arch_rethook_prepare);
  15
  16 void arch_rethook_fixup_return(struct pt_regs *regs,
  17                                unsigned long correct_ret_addr)
  18 {
  19         /* Replace fake return address with real one. */
  20         regs->gprs[14] = correct_ret_addr;
  21 }
  22 NOKPROBE_SYMBOL(arch_rethook_fixup_return);
  23
  24 /*
  25  * Called from arch_rethook_trampoline
  26  */
  27 unsigned long arch_rethook_trampoline_callback(struct pt_regs *regs)
  28 {
  29         return rethook_trampoline_handler(regs, regs->gprs[15]);
  30 }
  31 NOKPROBE_SYMBOL(arch_rethook_trampoline_callback);
  32
  33 /* assembler function that handles the rethook must not be probed itself */
  34 NOKPROBE_SYMBOL(arch_rethook_trampoline);