1 #ifndef GEN_ICOUNT_H
2 #define GEN_ICOUNT_H
3
4 #include "exec/exec-all.h"
5 #include "qemu/timer.h"
6
7 /* Helpers for instruction counting code generation. */
8
9 static TCGOp *icount_start_insn;
10
gen_io_start(void)11 static inline void gen_io_start(void)
12 {
13 TCGv_i32 tmp = tcg_const_i32(1);
14 tcg_gen_st_i32(tmp, cpu_env,
15 offsetof(ArchCPU, parent_obj.can_do_io) -
16 offsetof(ArchCPU, env));
17 tcg_temp_free_i32(tmp);
18 }
19
gen_tb_start(const TranslationBlock * tb)20 static inline void gen_tb_start(const TranslationBlock *tb)
21 {
22 TCGv_i32 count;
23
24 if (tb_cflags(tb) & CF_USE_ICOUNT) {
25 count = tcg_temp_local_new_i32();
26 } else {
27 count = tcg_temp_new_i32();
28 }
29
30 tcg_gen_ld_i32(count, cpu_env,
31 offsetof(ArchCPU, neg.icount_decr.u32) -
32 offsetof(ArchCPU, env));
33
34 if (tb_cflags(tb) & CF_USE_ICOUNT) {
35 /*
36 * We emit a sub with a dummy immediate argument. Keep the insn index
37 * of the sub so that we later (when we know the actual insn count)
38 * can update the argument with the actual insn count.
39 */
40 tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
41 icount_start_insn = tcg_last_op();
42 }
43
44 /*
45 * Emit the check against icount_decr.u32 to see if we should exit
46 * unless we suppress the check with CF_NOIRQ. If we are using
47 * icount and have suppressed interruption the higher level code
48 * should have ensured we don't run more instructions than the
49 * budget.
50 */
51 if (tb_cflags(tb) & CF_NOIRQ) {
52 tcg_ctx->exitreq_label = NULL;
53 } else {
54 tcg_ctx->exitreq_label = gen_new_label();
55 tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
56 }
57
58 if (tb_cflags(tb) & CF_USE_ICOUNT) {
59 tcg_gen_st16_i32(count, cpu_env,
60 offsetof(ArchCPU, neg.icount_decr.u16.low) -
61 offsetof(ArchCPU, env));
62 /*
63 * cpu->can_do_io is cleared automatically here at the beginning of
64 * each translation block. The cost is minimal and only paid for
65 * -icount, plus it would be very easy to forget doing it in the
66 * translator. Doing it here means we don't need a gen_io_end() to
67 * go with gen_io_start().
68 */
69 tcg_gen_st_i32(tcg_constant_i32(0), cpu_env,
70 offsetof(ArchCPU, parent_obj.can_do_io) -
71 offsetof(ArchCPU, env));
72 }
73
74 tcg_temp_free_i32(count);
75 }
76
gen_tb_end(const TranslationBlock * tb,int num_insns)77 static inline void gen_tb_end(const TranslationBlock *tb, int num_insns)
78 {
79 if (tb_cflags(tb) & CF_USE_ICOUNT) {
80 /*
81 * Update the num_insn immediate parameter now that we know
82 * the actual insn count.
83 */
84 tcg_set_insn_param(icount_start_insn, 2,
85 tcgv_i32_arg(tcg_constant_i32(num_insns)));
86 }
87
88 if (tcg_ctx->exitreq_label) {
89 gen_set_label(tcg_ctx->exitreq_label);
90 tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
91 }
92 }
93
94 #endif
95