+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+/* insert a jmp code */
+static __always_inline void set_jmp_op(void *from, void *to)
+{
+ struct __arch_jmp_op {
+ char op;
+ long raddr;
+ } __attribute__((packed)) *jop;
+ jop = (struct __arch_jmp_op *)from;
+ jop->raddr = (long)(to) - ((long)(from) + 5);
+ jop->op = RELATIVEJUMP_INSTRUCTION;
+}
+
+/*
+ * returns non-zero if opcodes can be boosted.
+ */
+static __always_inline int can_boost(kprobe_opcode_t *opcodes)
+{
+#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
+ (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
+ (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
+ (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
+ (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
+ << (row % 32))
+ /*
+ * Undefined/reserved opcodes, conditional jump, Opcode Extension
+ * Groups, and some special opcodes can not be boost.
+ */
+ static const unsigned long twobyte_is_boostable[256 / 32] = {
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ /* ------------------------------- */
+ W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */
+ W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */
+ W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */
+ W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */
+ W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */
+ W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */
+ W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */
+ W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */
+ W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */
+ W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */
+ W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */
+ W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */
+ W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */
+ W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */
+ W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */
+ W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */
+ /* ------------------------------- */
+ /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
+ };
+#undef W
+ kprobe_opcode_t opcode;
+ kprobe_opcode_t *orig_opcodes = opcodes;
+retry:
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+ return 0;
+ opcode = *(opcodes++);
+
+ /* 2nd-byte opcode */
+ if (opcode == 0x0f) {
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
+ return 0;
+ return test_bit(*opcodes, twobyte_is_boostable);
+ }
+
+ switch (opcode & 0xf0) {
+ case 0x60:
+ if (0x63 < opcode && opcode < 0x67)
+ goto retry; /* prefixes */
+ /* can't boost Address-size override and bound */
+ return (opcode != 0x62 && opcode != 0x67);
+ case 0x70:
+ return 0; /* can't boost conditional jump */
+ case 0xc0:
+ /* can't boost software-interruptions */
+ return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
+ case 0xd0:
+ /* can boost AA* and XLAT */
+ return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
+ case 0xe0:
+ /* can boost in/out and absolute jmps */
+ return ((opcode & 0x04) || opcode == 0xea);
+ case 0xf0:
+ if ((opcode & 0x0c) == 0 && opcode != 0xf1)
+ goto retry; /* lock/rep(ne) prefix */
+ /* clear and set flags can be boost */
+ return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
+ default:
+ if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
+ goto retry; /* prefixes */
+ /* can't boost CS override and call */
+ return (opcode != 0x2e && opcode != 0x9a);
+ }
+}
+