Watchpoint support (previous commit got eaten by Savannah server crash).

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2479 c046a42c-6fe2-441c-8c8c-71466251a162

Watchpoint support (previous commit got eaten by Savannah server crash).
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2479 c046a42c-6fe2-441c-8c8c-71466251a162
pbrook
1 parent b35d7448
Showing 6 changed files with 186 additions and 0 deletions
cpu-all.h
cpu-defs.h
cpu-exec.c
exec.c
gdbstub.c
target-arm/translate.c
@@ -775,10 +775,13 @@ extern int code_copy_enabled;
 #define CPU_INTERRUPT_FIQ    0x10 /* Fast interrupt pending.  */
 #define CPU_INTERRUPT_HALT   0x20 /* CPU halt wanted */
 #define CPU_INTERRUPT_SMI    0x40 /* (x86 only) SMI interrupt pending */
+#define CPU_INTERRUPT_DEBUG  0x80 /* Debug event occured.  */
 void cpu_interrupt(CPUState *s, int mask);
 void cpu_reset_interrupt(CPUState *env, int mask);
+int cpu_watchpoint_insert(CPUState *env, target_ulong addr);
+int cpu_watchpoint_remove(CPUState *env, target_ulong addr);
 int cpu_breakpoint_insert(CPUState *env, target_ulong pc);
 int cpu_breakpoint_remove(CPUState *env, target_ulong pc);
 void cpu_single_step(CPUState *env, int enabled);
@@ -76,6 +76,7 @@ typedef unsigned long ram_addr_t;
 #define EXCP_DEBUG      0x10002 /* cpu stopped after a breakpoint or singlestep */
 #define EXCP_HALTED     0x10003 /* cpu is halted (waiting for external event) */
 #define MAX_BREAKPOINTS 32
+#define MAX_WATCHPOINTS 32
 #define TB_JMP_CACHE_BITS 12
 #define TB_JMP_CACHE_SIZE (1 << TB_JMP_CACHE_BITS)
@@ -125,6 +126,13 @@ typedef struct CPUTLBEntry {
     int nb_breakpoints;                                                 \
     int singlestep_enabled;                                             \
                                                                         \
+    struct {                                                            \
+        target_ulong vaddr;                                             \
+        int is_ram;                                                     \
+    } watchpoint[MAX_WATCHPOINTS];                                      \
+    int nb_watchpoints;                                                 \
+    int watchpoint_hit;                                                 \
+                                                                        \
     void *next_cpu; /* next CPU sharing TB cache */                     \
     int cpu_index; /* CPU index (informative) */                        \
     /* user data */                                                     \
@@ -409,6 +409,11 @@ int cpu_exec(CPUState *env1)
 #endif	    
                 interrupt_request = env->interrupt_request;
                 if (__builtin_expect(interrupt_request, 0)) {
+                    if (interrupt_request & CPU_INTERRUPT_DEBUG) {
+                        env->interrupt_request &= ~CPU_INTERRUPT_DEBUG;
+                        env->exception_index = EXCP_DEBUG;
+                        cpu_loop_exit();
+                    }
 #if defined(TARGET_I386)
                     if ((interrupt_request & CPU_INTERRUPT_SMI) &&
                         !(env->hflags & HF_SMM_MASK)) {
@@ -128,6 +128,9 @@ CPUWriteMemoryFunc *io_mem_write[IO_MEM_NB_ENTRIES][4];
 CPUReadMemoryFunc *io_mem_read[IO_MEM_NB_ENTRIES][4];
 void *io_mem_opaque[IO_MEM_NB_ENTRIES];
 static int io_mem_nb;
+#if defined(CONFIG_SOFTMMU)
+static int io_mem_watch;
+#endif
 /* log support */
 char *logfilename = "/tmp/qemu.log";
@@ -274,6 +277,7 @@ void cpu_exec_init(CPUState *env)
         cpu_index++;
     }
     env->cpu_index = cpu_index;
+    env->nb_watchpoints = 0;
     *penv = env;
 }
@@ -1029,6 +1033,44 @@ static void breakpoint_invalidate(CPUState *env, target_ulong pc)
 }
 #endif
+/* Add a watchpoint.  */
+int  cpu_watchpoint_insert(CPUState *env, target_ulong addr)
+{
+    int i;
+
+    for (i = 0; i < env->nb_watchpoints; i++) {
+        if (addr == env->watchpoint[i].vaddr)
+            return 0;
+    }
+    if (env->nb_watchpoints >= MAX_WATCHPOINTS)
+        return -1;
+
+    i = env->nb_watchpoints++;
+    env->watchpoint[i].vaddr = addr;
+    tlb_flush_page(env, addr);
+    /* FIXME: This flush is needed because of the hack to make memory ops
+       terminate the TB.  It can be removed once the proper IO trap and
+       re-execute bits are in.  */
+    tb_flush(env);
+    return i;
+}
+
+/* Remove a watchpoint.  */
+int cpu_watchpoint_remove(CPUState *env, target_ulong addr)
+{
+    int i;
+
+    for (i = 0; i < env->nb_watchpoints; i++) {
+        if (addr == env->watchpoint[i].vaddr) {
+            env->nb_watchpoints--;
+            env->watchpoint[i] = env->watchpoint[env->nb_watchpoints];
+            tlb_flush_page(env, addr);
+            return 0;
+        }
+    }
+    return -1;
+}
+
 /* add a breakpoint. EXCP_DEBUG is returned by the CPU loop if a
    breakpoint is reached */
 int cpu_breakpoint_insert(CPUState *env, target_ulong pc)
@@ -1484,6 +1526,7 @@ int tlb_set_page_exec(CPUState *env, target_ulong vaddr,
     target_phys_addr_t addend;
     int ret;
     CPUTLBEntry *te;
+    int i;
     p = phys_page_find(paddr >> TARGET_PAGE_BITS);
     if (!p) {
@@ -1510,6 +1553,22 @@ int tlb_set_page_exec(CPUState *env, target_ulong vaddr,
             address = vaddr;
             addend = (unsigned long)phys_ram_base + (pd & TARGET_PAGE_MASK);
         }
+
+        /* Make accesses to pages with watchpoints go via the
+           watchpoint trap routines.  */
+        for (i = 0; i < env->nb_watchpoints; i++) {
+            if (vaddr == (env->watchpoint[i].vaddr & TARGET_PAGE_MASK)) {
+                if (address & ~TARGET_PAGE_MASK) {
+                    env->watchpoint[i].is_ram = 0;
+                    address = vaddr | io_mem_watch;
+                } else {
+                    env->watchpoint[i].is_ram = 1;
+                    /* TODO: Figure out how to make read watchpoints coexist
+                       with code.  */
+                    pd = (pd & TARGET_PAGE_MASK) | io_mem_watch | IO_MEM_ROMD;
+                }
+            }
+        }
         index = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
         addend -= vaddr;
@@ -1960,6 +2019,85 @@ static CPUWriteMemoryFunc *notdirty_mem_write[3] = {
     notdirty_mem_writel,
 };
+#if defined(CONFIG_SOFTMMU)
+/* Watchpoint access routines.  Watchpoints are inserted using TLB tricks,
+   so these check for a hit then pass through to the normal out-of-line
+   phys routines.  */
+static uint32_t watch_mem_readb(void *opaque, target_phys_addr_t addr)
+{
+    return ldub_phys(addr);
+}
+
+static uint32_t watch_mem_readw(void *opaque, target_phys_addr_t addr)
+{
+    return lduw_phys(addr);
+}
+
+static uint32_t watch_mem_readl(void *opaque, target_phys_addr_t addr)
+{
+    return ldl_phys(addr);
+}
+
+/* Generate a debug exception if a watchpoint has been hit.
+   Returns the real physical address of the access.  addr will be a host
+   address in the is_ram case.  */
+static target_ulong check_watchpoint(target_phys_addr_t addr)
+{
+    CPUState *env = cpu_single_env;
+    target_ulong watch;
+    target_ulong retaddr;
+    int i;
+
+    retaddr = addr;
+    for (i = 0; i < env->nb_watchpoints; i++) {
+        watch = env->watchpoint[i].vaddr;
+        if (((env->mem_write_vaddr ^ watch) & TARGET_PAGE_MASK) == 0) {
+            if (env->watchpoint[i].is_ram)
+                retaddr = addr - (unsigned long)phys_ram_base;
+            if (((addr ^ watch) & ~TARGET_PAGE_MASK) == 0) {
+                cpu_single_env->watchpoint_hit = i + 1;
+                cpu_interrupt(cpu_single_env, CPU_INTERRUPT_DEBUG);
+                break;
+            }
+        }
+    }
+    return retaddr;
+}
+
+static void watch_mem_writeb(void *opaque, target_phys_addr_t addr,
+                             uint32_t val)
+{
+    addr = check_watchpoint(addr);
+    stb_phys(addr, val);
+}
+
+static void watch_mem_writew(void *opaque, target_phys_addr_t addr,
+                             uint32_t val)
+{
+    addr = check_watchpoint(addr);
+    stw_phys(addr, val);
+}
+
+static void watch_mem_writel(void *opaque, target_phys_addr_t addr,
+                             uint32_t val)
+{
+    addr = check_watchpoint(addr);
+    stl_phys(addr, val);
+}
+
+static CPUReadMemoryFunc *watch_mem_read[3] = {
+    watch_mem_readb,
+    watch_mem_readw,
+    watch_mem_readl,
+};
+
+static CPUWriteMemoryFunc *watch_mem_write[3] = {
+    watch_mem_writeb,
+    watch_mem_writew,
+    watch_mem_writel,
+};
+#endif
+
 static void io_mem_init(void)
 {
     cpu_register_io_memory(IO_MEM_ROM >> IO_MEM_SHIFT, error_mem_read, unassigned_mem_write, NULL);
@@ -1967,6 +2105,10 @@ static void io_mem_init(void)
     cpu_register_io_memory(IO_MEM_NOTDIRTY >> IO_MEM_SHIFT, error_mem_read, notdirty_mem_write, NULL);
     io_mem_nb = 5;
+#if defined(CONFIG_SOFTMMU)
+    io_mem_watch = cpu_register_io_memory(-1, watch_mem_read,
+                                          watch_mem_write, NULL);
+#endif
     /* alloc dirty bits array */
     phys_ram_dirty = qemu_vmalloc(phys_ram_size >> TARGET_PAGE_BITS);
     memset(phys_ram_dirty, 0xff, phys_ram_size >> TARGET_PAGE_BITS);
@@ -856,6 +856,12 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
             if (cpu_breakpoint_insert(env, addr) < 0)
                 goto breakpoint_error;
             put_packet(s, "OK");
+#ifndef CONFIG_USER_ONLY
+        } else if (type == 2) {
+            if (cpu_watchpoint_insert(env, addr) < 0)
+                goto breakpoint_error;
+            put_packet(s, "OK");
+#endif
         } else {
         breakpoint_error:
             put_packet(s, "E22");
@@ -872,6 +878,11 @@ static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
         if (type == 0 || type == 1) {
             cpu_breakpoint_remove(env, addr);
             put_packet(s, "OK");
+#ifndef CONFIG_USER_ONLY
+        } else if (type == 2) {
+            cpu_watchpoint_remove(env, addr);
+            put_packet(s, "OK");
+#endif
         } else {
             goto breakpoint_error;
         }
@@ -914,6 +925,13 @@ static void gdb_vm_stopped(void *opaque, int reason)
     cpu_single_step(s->env, 0);
     if (reason == EXCP_DEBUG) {
+        if (s->env->watchpoint_hit) {
+            snprintf(buf, sizeof(buf), "T%02xwatch:%x;", SIGTRAP,
+                     s->env->watchpoint[s->env->watchpoint_hit - 1].vaddr);
+            put_packet(s, buf);
+            s->env->watchpoint_hit = 0;
+            return;
+        }
 	tb_flush(s->env);
         ret = SIGTRAP;
     } else if (reason == EXCP_INTERRUPT) {
@@ -45,6 +45,7 @@ typedef struct DisasContext {
     struct TranslationBlock *tb;
     int singlestep_enabled;
     int thumb;
+    int is_mem;
 #if !defined(CONFIG_USER_ONLY)
     int user;
 #endif
@@ -290,6 +291,7 @@ static inline void gen_bx(DisasContext *s)
 #define gen_ldst(name, s) gen_op_##name##_raw()
 #else
 #define gen_ldst(name, s) do { \
+    s->is_mem = 1; \
     if (IS_USER(s)) \
         gen_op_##name##_user(); \
     else \
@@ -1612,6 +1614,7 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
                 gen_add_data_offset(s, insn);
             if (insn & (1 << 20)) {
                 /* load */
+                s->is_mem = 1;
 #if defined(CONFIG_USER_ONLY)
                 if (insn & (1 << 22))
                     gen_op_ldub_raw();
@@ -2409,6 +2412,7 @@ static inline int gen_intermediate_code_internal(CPUState *env,
     dc->singlestep_enabled = env->singlestep_enabled;
     dc->condjmp = 0;
     dc->thumb = env->thumb;
+    dc->is_mem = 0;
 #if !defined(CONFIG_USER_ONLY)
     dc->user = (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_USR;
 #endif
@@ -2447,6 +2451,12 @@ static inline int gen_intermediate_code_internal(CPUState *env,
             gen_set_label(dc->condlabel);
             dc->condjmp = 0;
         }
+        /* Terminate the TB on memory ops if watchpoints are present.  */
+        /* FIXME: This should be replacd by the deterministic execution
+         * IRQ raising bits.  */
+        if (dc->is_mem && env->nb_watchpoints)
+            break;
+
         /* Translation stops when a conditional branch is enoutered.
          * Otherwise the subsequent code could get translated several times.
          * Also stop translation when a page boundary is reached.  This