LXR linux/arch/arm/probes/kprobes/checkers-common.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * arch/arm/probes/kprobes/checkers-common.c
   4 *
   5 * Copyright (C) 2014 Huawei Inc.
   6 */
   7
   8#include <linux/kernel.h>
   9#include "../decode.h"
  10#include "../decode-arm.h"
  11#include "checkers.h"
  12
  13enum probes_insn checker_stack_use_none(probes_opcode_t insn,
  14                struct arch_probes_insn *asi,
  15                const struct decode_header *h)
  16{
  17        asi->stack_space = 0;
  18        return INSN_GOOD_NO_SLOT;
  19}
  20
  21enum probes_insn checker_stack_use_unknown(probes_opcode_t insn,
  22                struct arch_probes_insn *asi,
  23                const struct decode_header *h)
  24{
  25        asi->stack_space = -1;
  26        return INSN_GOOD_NO_SLOT;
  27}
  28
  29#ifdef CONFIG_THUMB2_KERNEL
  30enum probes_insn checker_stack_use_imm_0xx(probes_opcode_t insn,
  31                struct arch_probes_insn *asi,
  32                const struct decode_header *h)
  33{
  34        int imm = insn & 0xff;
  35        asi->stack_space = imm;
  36        return INSN_GOOD_NO_SLOT;
  37}
  38
  39/*
  40 * Different from other insn uses imm8, the real addressing offset of
  41 * STRD in T32 encoding should be imm8 * 4. See ARMARM description.
  42 */
  43enum probes_insn checker_stack_use_t32strd(probes_opcode_t insn,
  44                struct arch_probes_insn *asi,
  45                const struct decode_header *h)
  46{
  47        int imm = insn & 0xff;
  48        asi->stack_space = imm << 2;
  49        return INSN_GOOD_NO_SLOT;
  50}
  51#else
  52enum probes_insn checker_stack_use_imm_x0x(probes_opcode_t insn,
  53                struct arch_probes_insn *asi,
  54                const struct decode_header *h)
  55{
  56        int imm = ((insn & 0xf00) >> 4) + (insn & 0xf);
  57        asi->stack_space = imm;
  58        return INSN_GOOD_NO_SLOT;
  59}
  60#endif
  61
  62enum probes_insn checker_stack_use_imm_xxx(probes_opcode_t insn,
  63                struct arch_probes_insn *asi,
  64                const struct decode_header *h)
  65{
  66        int imm = insn & 0xfff;
  67        asi->stack_space = imm;
  68        return INSN_GOOD_NO_SLOT;
  69}
  70
  71enum probes_insn checker_stack_use_stmdx(probes_opcode_t insn,
  72                struct arch_probes_insn *asi,
  73                const struct decode_header *h)
  74{
  75        unsigned int reglist = insn & 0xffff;
  76        int pbit = insn & (1 << 24);
  77        asi->stack_space = (hweight32(reglist) - (!pbit ? 1 : 0)) * 4;
  78
  79        return INSN_GOOD_NO_SLOT;
  80}
  81
  82const union decode_action stack_check_actions[] = {
  83        [STACK_USE_NONE] = {.decoder = checker_stack_use_none},
  84        [STACK_USE_UNKNOWN] = {.decoder = checker_stack_use_unknown},
  85#ifdef CONFIG_THUMB2_KERNEL
  86        [STACK_USE_FIXED_0XX] = {.decoder = checker_stack_use_imm_0xx},
  87        [STACK_USE_T32STRD] = {.decoder = checker_stack_use_t32strd},
  88#else
  89        [STACK_USE_FIXED_X0X] = {.decoder = checker_stack_use_imm_x0x},
  90#endif
  91        [STACK_USE_FIXED_XXX] = {.decoder = checker_stack_use_imm_xxx},
  92        [STACK_USE_STMDX] = {.decoder = checker_stack_use_stmdx},
  93};
  94