arch/csky/kernel/jump_label.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <linux/jump_label.h>
   4 #include <linux/kernel.h>
   5 #include <linux/memory.h>
   6 #include <linux/mutex.h>
   7 #include <linux/uaccess.h>
   8 #include <asm/cacheflush.h>
   9
  10 #define NOP32_HI        0xc400
  11 #define NOP32_LO        0x4820
  12 #define BSR_LINK        0xe000
  13
  14 void arch_jump_label_transform(struct jump_entry *entry,
  15                                enum jump_label_type type)
  16 {
  17         unsigned long addr = jump_entry_code(entry);
  18         u16 insn[2];
  19         int ret = 0;
  20
  21         if (type == JUMP_LABEL_JMP) {
  22                 long offset = jump_entry_target(entry) - jump_entry_code(entry);
  23
  24                 if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
  25                         return;
  26
  27                 offset = offset >> 1;
  28
  29                 insn[0] = BSR_LINK |
  30                         ((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
  31                 insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
  32         } else {
  33                 insn[0] = NOP32_HI;
  34                 insn[1] = NOP32_LO;
  35         }
  36
  37         ret = copy_to_kernel_nofault((void *)addr, insn, 4);
  38         WARN_ON(ret);
  39
  40         flush_icache_range(addr, addr + 4);
  41 }
  42
  43 void arch_jump_label_transform_static(struct jump_entry *entry,
  44                                       enum jump_label_type type)
  45 {
  46         /*
  47          * We use the same instructions in the arch_static_branch and
  48          * arch_static_branch_jump inline functions, so there's no
  49          * need to patch them up here.
  50          * The core will call arch_jump_label_transform  when those
  51          * instructions need to be replaced.
  52          */
  53         arch_jump_label_transform(entry, type);
  54 }