target-lm32: add breakpoint/watchpoint support

This patch adds in-target breakpoint and watchpoint support.

Signed-off-by: Michael Walle <michael@walle.cc>

target-lm32/TODO

@@ -1,3 +1 @@
-* disassembler (lm32-dis.c)
 * linux-user emulation
-* native bp/wp emulation (?)

target-lm32/cpu.c

@@ -153,6 +153,7 @@ static void lm32_cpu_initfn(Object *obj)
     if (tcg_enabled() && !tcg_initialized) {
         tcg_initialized = true;
         lm32_translate_init();
+        cpu_set_debug_excp_handler(lm32_debug_excp_handler);
     }
 }
 

target-lm32/cpu.h

@@ -163,8 +163,11 @@ struct CPULM32State {
 
     /* debug registers */
     uint32_t dc;        /* debug control */
-    uint32_t bp[4];     /* breakpoint addresses */
-    uint32_t wp[4];     /* watchpoint addresses */
+    uint32_t bp[4];     /* breakpoints */
+    uint32_t wp[4];     /* watchpoints */
+
+    CPUBreakpoint * cpu_breakpoint[4];
+    CPUWatchpoint * cpu_watchpoint[4];
 
     CPU_COMMON
 
@@ -181,6 +184,19 @@ struct CPULM32State {
 
 };
 
+typedef enum {
+    LM32_WP_DISABLED = 0,
+    LM32_WP_READ,
+    LM32_WP_WRITE,
+    LM32_WP_READ_WRITE,
+} lm32_wp_t;
+
+static inline lm32_wp_t lm32_wp_type(uint32_t dc, int idx)
+{
+    assert(idx < 4);
+    return (dc >> (idx+1)*2) & 0x3;
+}
+
 #include "cpu-qom.h"
 
 LM32CPU *cpu_lm32_init(const char *cpu_model);
@@ -193,6 +209,13 @@ int cpu_lm32_signal_handler(int host_signum, void *pinfo,
 void lm32_cpu_list(FILE *f, fprintf_function cpu_fprintf);
 void lm32_translate_init(void);
 void cpu_lm32_set_phys_msb_ignore(CPULM32State *env, int value);
+void QEMU_NORETURN raise_exception(CPULM32State *env, int index);
+void lm32_debug_excp_handler(CPULM32State *env);
+void lm32_breakpoint_insert(CPULM32State *env, int index, target_ulong address);
+void lm32_breakpoint_remove(CPULM32State *env, int index);
+void lm32_watchpoint_insert(CPULM32State *env, int index, target_ulong address,
+        lm32_wp_t wp_type);
+void lm32_watchpoint_remove(CPULM32State *env, int index);
 
 static inline CPULM32State *cpu_init(const char *cpu_model)
 {

target-lm32/helper.c

@@ -49,6 +49,96 @@ hwaddr lm32_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
     }
 }
 
+void lm32_breakpoint_insert(CPULM32State *env, int idx, target_ulong address)
+{
+    cpu_breakpoint_insert(env, address, BP_CPU, &env->cpu_breakpoint[idx]);
+}
+
+void lm32_breakpoint_remove(CPULM32State *env, int idx)
+{
+    if (!env->cpu_breakpoint[idx]) {
+        return;
+    }
+
+    cpu_breakpoint_remove_by_ref(env, env->cpu_breakpoint[idx]);
+    env->cpu_breakpoint[idx] = NULL;
+}
+
+void lm32_watchpoint_insert(CPULM32State *env, int idx, target_ulong address,
+                            lm32_wp_t wp_type)
+{
+    int flags = 0;
+
+    switch (wp_type) {
+    case LM32_WP_DISABLED:
+        /* nothing to to */
+        break;
+    case LM32_WP_READ:
+        flags = BP_CPU | BP_STOP_BEFORE_ACCESS | BP_MEM_READ;
+        break;
+    case LM32_WP_WRITE:
+        flags = BP_CPU | BP_STOP_BEFORE_ACCESS | BP_MEM_WRITE;
+        break;
+    case LM32_WP_READ_WRITE:
+        flags = BP_CPU | BP_STOP_BEFORE_ACCESS | BP_MEM_ACCESS;
+        break;
+    }
+
+    if (flags != 0) {
+        cpu_watchpoint_insert(env, address, 1, flags,
+                &env->cpu_watchpoint[idx]);
+    }
+}
+
+void lm32_watchpoint_remove(CPULM32State *env, int idx)
+{
+    if (!env->cpu_watchpoint[idx]) {
+        return;
+    }
+
+    cpu_watchpoint_remove_by_ref(env, env->cpu_watchpoint[idx]);
+    env->cpu_watchpoint[idx] = NULL;
+}
+
+static bool check_watchpoints(CPULM32State *env)
+{
+    LM32CPU *cpu = lm32_env_get_cpu(env);
+    int i;
+
+    for (i = 0; i < cpu->num_watchpoints; i++) {
+        if (env->cpu_watchpoint[i] &&
+                env->cpu_watchpoint[i]->flags & BP_WATCHPOINT_HIT) {
+            return true;
+        }
+    }
+    return false;
+}
+
+void lm32_debug_excp_handler(CPULM32State *env)
+{
+    CPUBreakpoint *bp;
+
+    if (env->watchpoint_hit) {
+        if (env->watchpoint_hit->flags & BP_CPU) {
+            env->watchpoint_hit = NULL;
+            if (check_watchpoints(env)) {
+                raise_exception(env, EXCP_WATCHPOINT);
+            } else {
+                cpu_resume_from_signal(env, NULL);
+            }
+        }
+    } else {
+        QTAILQ_FOREACH(bp, &env->breakpoints, entry) {
+            if (bp->pc == env->pc) {
+                if (bp->flags & BP_CPU) {
+                    raise_exception(env, EXCP_BREAKPOINT);
+                }
+                break;
+            }
+        }
+    }
+}
+
 void lm32_cpu_do_interrupt(CPUState *cs)
 {
     LM32CPU *cpu = LM32_CPU(cs);

target-lm32/helper.h

@@ -2,6 +2,9 @@
 
 DEF_HELPER_2(raise_exception, void, env, i32)
 DEF_HELPER_1(hlt, void, env)
+DEF_HELPER_3(wcsr_bp, void, env, i32, i32)
+DEF_HELPER_3(wcsr_wp, void, env, i32, i32)
+DEF_HELPER_2(wcsr_dc, void, env, i32)
 DEF_HELPER_2(wcsr_im, void, env, i32)
 DEF_HELPER_2(wcsr_ip, void, env, i32)
 DEF_HELPER_2(wcsr_jtx, void, env, i32)

target-lm32/op_helper.c

@@ -19,12 +19,17 @@
 #define SHIFT 3
 #include "exec/softmmu_template.h"
 
-void HELPER(raise_exception)(CPULM32State *env, uint32_t index)
+void raise_exception(CPULM32State *env, int index)
 {
     env->exception_index = index;
     cpu_loop_exit(env);
 }
 
+void HELPER(raise_exception)(CPULM32State *env, uint32_t index)
+{
+    raise_exception(env, index);
+}
+
 void HELPER(hlt)(CPULM32State *env)
 {
     CPUState *cs = CPU(lm32_env_get_cpu(env));
@@ -34,6 +39,57 @@ void HELPER(hlt)(CPULM32State *env)
     cpu_loop_exit(env);
 }
 
+void HELPER(wcsr_bp)(CPULM32State *env, uint32_t bp, uint32_t idx)
+{
+    uint32_t addr = bp & ~1;
+
+    assert(idx < 4);
+
+    env->bp[idx] = bp;
+    lm32_breakpoint_remove(env, idx);
+    if (bp & 1) {
+        lm32_breakpoint_insert(env, idx, addr);
+    }
+}
+
+void HELPER(wcsr_wp)(CPULM32State *env, uint32_t wp, uint32_t idx)
+{
+    lm32_wp_t wp_type;
+
+    assert(idx < 4);
+
+    env->wp[idx] = wp;
+
+    wp_type = lm32_wp_type(env->dc, idx);
+    lm32_watchpoint_remove(env, idx);
+    if (wp_type != LM32_WP_DISABLED) {
+        lm32_watchpoint_insert(env, idx, wp, wp_type);
+    }
+}
+
+void HELPER(wcsr_dc)(CPULM32State *env, uint32_t dc)
+{
+    uint32_t old_dc;
+    int i;
+    lm32_wp_t old_type;
+    lm32_wp_t new_type;
+
+    old_dc = env->dc;
+    env->dc = dc;
+
+    for (i = 0; i < 4; i++) {
+        old_type = lm32_wp_type(old_dc, i);
+        new_type = lm32_wp_type(dc, i);
+
+        if (old_type != new_type) {
+            lm32_watchpoint_remove(env, i);
+            if (new_type != LM32_WP_DISABLED) {
+                lm32_watchpoint_insert(env, i, env->wp[i], new_type);
+            }
+        }
+    }
+}
+
 void HELPER(wcsr_im)(CPULM32State *env, uint32_t im)
 {
     lm32_pic_set_im(env->pic_state, im);

target-lm32/translate.c

@@ -876,7 +876,7 @@ static void dec_wcsr(DisasContext *dc)
         gen_helper_wcsr_jrx(cpu_env, cpu_R[dc->r1]);
         break;
     case CSR_DC:
-        tcg_gen_mov_tl(cpu_dc, cpu_R[dc->r1]);
+        gen_helper_wcsr_dc(cpu_env, cpu_R[dc->r1]);
         break;
     case CSR_BP0:
     case CSR_BP1:
@@ -888,7 +888,7 @@ static void dec_wcsr(DisasContext *dc)
                           "breakpoint #%i is not available\n", no);
             break;
         }
-        tcg_gen_mov_tl(cpu_bp[no], cpu_R[dc->r1]);
+        gen_helper_wcsr_bp(cpu_env, cpu_R[dc->r1], tcg_const_i32(no));
         break;
     case CSR_WP0:
     case CSR_WP1:
@@ -900,7 +900,7 @@ static void dec_wcsr(DisasContext *dc)
                           "watchpoint #%i is not available\n", no);
             break;
         }
-        tcg_gen_mov_tl(cpu_wp[no], cpu_R[dc->r1]);
+        gen_helper_wcsr_wp(cpu_env, cpu_R[dc->r1], tcg_const_i32(no));
         break;
     case CSR_CC:
     case CSR_CFG: