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target-lm32: stop VM on illegal or unknown instruction

Instead of translating the instruction to a no-op, pause the VM and display
a message to the user.

As a side effect, this also works for instructions where the operands are
only known at runtime.

Signed-off-by: Michael Walle <michael@walle.cc>
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1 parent c090f66 commit ea58bb33c57895e2b6fed1e2a3063cb5826aa818 @mwalle committed Sep 23, 2013
Showing with 79 additions and 30 deletions.
  1. +1 −0 target-lm32/helper.h
  2. +17 −0 target-lm32/op_helper.c
  3. +61 −30 target-lm32/translate.c
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@@ -13,5 +13,6 @@ DEF_HELPER_1(rcsr_im, i32, env)
DEF_HELPER_1(rcsr_ip, i32, env)
DEF_HELPER_1(rcsr_jtx, i32, env)
DEF_HELPER_1(rcsr_jrx, i32, env)
+DEF_HELPER_1(ill, void, env)
#include "exec/def-helper.h"
View
@@ -8,6 +8,10 @@
#include "exec/softmmu_exec.h"
+#ifndef CONFIG_USER_ONLY
+#include "sysemu/sysemu.h"
+#endif
+
#if !defined(CONFIG_USER_ONLY)
#define MMUSUFFIX _mmu
#define SHIFT 0
@@ -39,6 +43,19 @@ void HELPER(hlt)(CPULM32State *env)
cpu_loop_exit(env);
}
+void HELPER(ill)(CPULM32State *env)
+{
+#ifndef CONFIG_USER_ONLY
+ CPUState *cs = CPU(lm32_env_get_cpu(env));
+ fprintf(stderr, "VM paused due to illegal instruction. "
+ "Connect a debugger or switch to the monitor console "
+ "to find out more.\n");
+ qemu_system_vmstop_request(RUN_STATE_PAUSED);
+ cs->halted = 1;
+ raise_exception(env, EXCP_HALTED);
+#endif
+}
+
void HELPER(wcsr_bp)(CPULM32State *env, uint32_t bp, uint32_t idx)
{
uint32_t addr = bp & ~1;
View
@@ -119,6 +119,12 @@ static inline void t_gen_raise_exception(DisasContext *dc, uint32_t index)
tcg_temp_free_i32(tmp);
}
+static inline void t_gen_illegal_insn(DisasContext *dc)
+{
+ tcg_gen_movi_tl(cpu_pc, dc->pc);
+ gen_helper_ill(cpu_env);
+}
+
static void gen_goto_tb(DisasContext *dc, int n, target_ulong dest)
{
TranslationBlock *tb;
@@ -422,6 +428,7 @@ static void dec_divu(DisasContext *dc)
if (!(dc->def->features & LM32_FEATURE_DIVIDE)) {
qemu_log_mask(LOG_GUEST_ERROR, "hardware divider is not available\n");
+ t_gen_illegal_insn(dc);
return;
}
@@ -501,6 +508,7 @@ static void dec_modu(DisasContext *dc)
if (!(dc->def->features & LM32_FEATURE_DIVIDE)) {
qemu_log_mask(LOG_GUEST_ERROR, "hardware divider is not available\n");
+ t_gen_illegal_insn(dc);
return;
}
@@ -524,6 +532,7 @@ static void dec_mul(DisasContext *dc)
if (!(dc->def->features & LM32_FEATURE_MULTIPLY)) {
qemu_log_mask(LOG_GUEST_ERROR,
"hardware multiplier is not available\n");
+ t_gen_illegal_insn(dc);
return;
}
@@ -592,17 +601,18 @@ static void dec_scall(DisasContext *dc)
LOG_DIS("scall\n");
} else if (dc->imm5 == 2) {
LOG_DIS("break\n");
- } else {
- qemu_log_mask(LOG_GUEST_ERROR, "invalid opcode @0x%x", dc->pc);
- return;
}
if (dc->imm5 == 7) {
tcg_gen_movi_tl(cpu_pc, dc->pc);
t_gen_raise_exception(dc, EXCP_SYSTEMCALL);
- } else {
+ } else if (dc->imm5 == 2) {
tcg_gen_movi_tl(cpu_pc, dc->pc);
t_gen_raise_exception(dc, EXCP_BREAKPOINT);
+ } else {
+ qemu_log_mask(LOG_GUEST_ERROR, "invalid opcode @0x%x", dc->pc);
+ t_gen_illegal_insn(dc);
+ return;
}
}
@@ -678,6 +688,7 @@ static void dec_sextb(DisasContext *dc)
if (!(dc->def->features & LM32_FEATURE_SIGN_EXTEND)) {
qemu_log_mask(LOG_GUEST_ERROR,
"hardware sign extender is not available\n");
+ t_gen_illegal_insn(dc);
return;
}
@@ -691,6 +702,7 @@ static void dec_sexth(DisasContext *dc)
if (!(dc->def->features & LM32_FEATURE_SIGN_EXTEND)) {
qemu_log_mask(LOG_GUEST_ERROR,
"hardware sign extender is not available\n");
+ t_gen_illegal_insn(dc);
return;
}
@@ -719,6 +731,7 @@ static void dec_sl(DisasContext *dc)
if (!(dc->def->features & LM32_FEATURE_SHIFT)) {
qemu_log_mask(LOG_GUEST_ERROR, "hardware shifter is not available\n");
+ t_gen_illegal_insn(dc);
return;
}
@@ -740,24 +753,32 @@ static void dec_sr(DisasContext *dc)
LOG_DIS("sr r%d, r%d, r%d\n", dc->r2, dc->r0, dc->r1);
}
- if (!(dc->def->features & LM32_FEATURE_SHIFT)) {
- if (dc->format == OP_FMT_RI) {
- /* TODO: check r1 == 1 during runtime */
- } else {
- if (dc->imm5 != 1) {
- qemu_log_mask(LOG_GUEST_ERROR,
- "hardware shifter is not available\n");
- return;
- }
- }
- }
-
+ /* The real CPU (w/o hardware shifter) only supports right shift by exactly
+ * one bit */
if (dc->format == OP_FMT_RI) {
+ if (!(dc->def->features & LM32_FEATURE_SHIFT) && (dc->imm5 != 1)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "hardware shifter is not available\n");
+ t_gen_illegal_insn(dc);
+ return;
+ }
tcg_gen_sari_tl(cpu_R[dc->r1], cpu_R[dc->r0], dc->imm5);
} else {
- TCGv t0 = tcg_temp_new();
+ int l1 = gen_new_label();
+ int l2 = gen_new_label();
+ TCGv t0 = tcg_temp_local_new();
tcg_gen_andi_tl(t0, cpu_R[dc->r1], 0x1f);
+
+ if (!(dc->def->features & LM32_FEATURE_SHIFT)) {
+ tcg_gen_brcondi_tl(TCG_COND_EQ, t0, 1, l1);
+ t_gen_illegal_insn(dc);
+ tcg_gen_br(l2);
+ }
+
+ gen_set_label(l1);
tcg_gen_sar_tl(cpu_R[dc->r2], cpu_R[dc->r0], t0);
+ gen_set_label(l2);
+
tcg_temp_free(t0);
}
}
@@ -770,24 +791,30 @@ static void dec_sru(DisasContext *dc)
LOG_DIS("sru r%d, r%d, r%d\n", dc->r2, dc->r0, dc->r1);
}
- if (!(dc->def->features & LM32_FEATURE_SHIFT)) {
- if (dc->format == OP_FMT_RI) {
- /* TODO: check r1 == 1 during runtime */
- } else {
- if (dc->imm5 != 1) {
- qemu_log_mask(LOG_GUEST_ERROR,
- "hardware shifter is not available\n");
- return;
- }
- }
- }
-
if (dc->format == OP_FMT_RI) {
+ if (!(dc->def->features & LM32_FEATURE_SHIFT) && (dc->imm5 != 1)) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "hardware shifter is not available\n");
+ t_gen_illegal_insn(dc);
+ return;
+ }
tcg_gen_shri_tl(cpu_R[dc->r1], cpu_R[dc->r0], dc->imm5);
} else {
- TCGv t0 = tcg_temp_new();
+ int l1 = gen_new_label();
+ int l2 = gen_new_label();
+ TCGv t0 = tcg_temp_local_new();
tcg_gen_andi_tl(t0, cpu_R[dc->r1], 0x1f);
+
+ if (!(dc->def->features & LM32_FEATURE_SHIFT)) {
+ tcg_gen_brcondi_tl(TCG_COND_EQ, t0, 1, l1);
+ t_gen_illegal_insn(dc);
+ tcg_gen_br(l2);
+ }
+
+ gen_set_label(l1);
tcg_gen_shr_tl(cpu_R[dc->r2], cpu_R[dc->r0], t0);
+ gen_set_label(l2);
+
tcg_temp_free(t0);
}
}
@@ -816,6 +843,7 @@ static void dec_user(DisasContext *dc)
LOG_DIS("user");
qemu_log_mask(LOG_GUEST_ERROR, "user instruction undefined\n");
+ t_gen_illegal_insn(dc);
}
static void dec_wcsr(DisasContext *dc)
@@ -883,6 +911,7 @@ static void dec_wcsr(DisasContext *dc)
if (dc->def->num_breakpoints <= no) {
qemu_log_mask(LOG_GUEST_ERROR,
"breakpoint #%i is not available\n", no);
+ t_gen_illegal_insn(dc);
break;
}
gen_helper_wcsr_bp(cpu_env, cpu_R[dc->r1], tcg_const_i32(no));
@@ -895,6 +924,7 @@ static void dec_wcsr(DisasContext *dc)
if (dc->def->num_watchpoints <= no) {
qemu_log_mask(LOG_GUEST_ERROR,
"watchpoint #%i is not available\n", no);
+ t_gen_illegal_insn(dc);
break;
}
gen_helper_wcsr_wp(cpu_env, cpu_R[dc->r1], tcg_const_i32(no));
@@ -953,6 +983,7 @@ static void dec_xor(DisasContext *dc)
static void dec_ill(DisasContext *dc)
{
qemu_log_mask(LOG_GUEST_ERROR, "invalid opcode 0x%02x\n", dc->opcode);
+ t_gen_illegal_insn(dc);
}
typedef void (*DecoderInfo)(DisasContext *dc);

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