Add configurable datacount for debug module

This commit adds support for configuring the number of data registers available
in the debug module. Previously, the debug module had a fixed datasize of 2,
but now users can specify the number of data registers using the --dm-datacount
option when running spike.

The changes include:
- Adding a datacount parameter to debug_module_config_t
- Making dmdata a std::vector instead of a fixed array
- Validating that datacount is between 1 and 12
- Updating the debug module to use the configured datacount
- Adding command-line option to set datacount
- Updating documentation in help output

Signed-off-by: Farid Khaydari <[email protected]>

Author: fk-sc

riscv/debug_module.cc

@@ -1,4 +1,8 @@
+#include <algorithm>
+#include <array>
 #include <cassert>
+#include <iterator>
+#include <limits>
 
 #include "simif.h"
 #include "devices.h"
@@ -32,6 +36,25 @@ static unsigned field_width(unsigned n)
 
 ///////////////////////// debug_module_t
 
+static bool region_descriptor_comparator(const region_descriptor &lhs,
+                                  const region_descriptor &rhs) {
+  return lhs.addr < rhs.addr;
+}
+
+template <typename It>
+static bool has_intersection(It begin, It end) {
+  assert(std::is_sorted(begin, end, region_descriptor_comparator));
+
+  // If current interval's end > next interval's start, they intersect
+  auto intersecion =
+      std::adjacent_find(begin, end, [](const auto &lhs, const auto &rhs) {
+        assert(std::numeric_limits<reg_t>::max() - lhs.addr >= lhs.len);
+        return lhs.addr + lhs.len > rhs.addr;
+      });
+
+  return intersecion != end;
+}
+
 debug_module_t::debug_module_t(simif_t *sim, const debug_module_config_t &config) :
   config(config),
   program_buffer_bytes((config.support_impebreak ? 4 : 0) + 4*config.progbufsize),
@@ -57,11 +80,18 @@ debug_module_t::debug_module_t(simif_t *sim, const debug_module_config_t &config
     exit(1);
   }
 
+  constexpr unsigned max_data_reg = 12;
+  constexpr unsigned min_data_reg = 1;
+  if (config.datacount < min_data_reg || config.datacount > max_data_reg) {
+    fprintf(stderr, "dm-datacount must be between 1 and 12 (got %u)\n", config.datacount);
+    exit(1);
+  }
+
+  dmdata.resize(config.datacount * dmdata_reg_size);
   program_buffer = new uint8_t[program_buffer_bytes];
 
   memset(debug_rom_flags, 0, sizeof(debug_rom_flags));
   memset(program_buffer, 0, program_buffer_bytes);
-  memset(dmdata, 0, sizeof(dmdata));
 
   if (config.support_impebreak) {
     program_buffer[4*config.progbufsize] = ebreak();
@@ -78,6 +108,20 @@ debug_module_t::debug_module_t(simif_t *sim, const debug_module_config_t &config
     hart_available_state[i] = true;
   }
 
+  debug_memory_regions = {
+      region_descriptor{DEBUG_ROM_ENTRY, debug_rom_raw_len, debug_rom_raw},
+      region_descriptor{DEBUG_ROM_WHERETO, sizeof(debug_rom_whereto), debug_rom_whereto},
+      region_descriptor{DEBUG_ROM_FLAGS, sizeof(debug_rom_flags), debug_rom_flags},
+      region_descriptor{debug_data_start, dmdata.size(), dmdata.data()},
+      region_descriptor{debug_abstract_start, sizeof(debug_abstract), debug_abstract},
+      region_descriptor{debug_progbuf_start, program_buffer_bytes, program_buffer},
+  };
+
+  std::sort(debug_memory_regions.begin(), debug_memory_regions.end(),
+            region_descriptor_comparator);
+  assert(!has_intersection(debug_memory_regions.begin(),
+                           debug_memory_regions.end()));
+
   reset();
 }
 
@@ -100,7 +144,7 @@ void debug_module_t::reset()
   dmstatus.version = 2;
 
   memset(&abstractcs, 0, sizeof(abstractcs));
-  abstractcs.datacount = sizeof(dmdata) / 4;
+  abstractcs.datacount = config.datacount;
   abstractcs.progbufsize = config.progbufsize;
 
   memset(&abstractauto, 0, sizeof(abstractauto));
@@ -122,38 +166,27 @@ void debug_module_t::reset()
   challenge = random();
 }
 
+static bool belongs_to_range(reg_t access_addr, size_t access_len,
+                             reg_t range_addr, size_t range_len)
+{
+  assert(std::numeric_limits<reg_t>::max() - access_addr >= access_len);
+  assert(std::numeric_limits<reg_t>::max() - range_addr >= range_len);
+  return access_addr >= range_addr && (access_addr < range_addr + range_len) &&
+         ((access_addr + access_len) <= (range_addr + range_len));
+}
+
 bool debug_module_t::load(reg_t addr, size_t len, uint8_t* bytes)
 {
   addr = DEBUG_START + addr;
 
-  if (addr >= DEBUG_ROM_ENTRY &&
-      (addr + len) <= (DEBUG_ROM_ENTRY + debug_rom_raw_len)) {
-    memcpy(bytes, debug_rom_raw + addr - DEBUG_ROM_ENTRY, len);
-    return true;
-  }
-
-  if (addr >= DEBUG_ROM_WHERETO && (addr + len) <= (DEBUG_ROM_WHERETO + 4)) {
-    memcpy(bytes, debug_rom_whereto + addr - DEBUG_ROM_WHERETO, len);
-    return true;
-  }
-
-  if (addr >= DEBUG_ROM_FLAGS && ((addr + len) <= DEBUG_ROM_FLAGS + 1024)) {
-    memcpy(bytes, debug_rom_flags + addr - DEBUG_ROM_FLAGS, len);
-    return true;
-  }
-
-  if (addr >= debug_abstract_start && ((addr + len) <= (debug_abstract_start + sizeof(debug_abstract)))) {
-    memcpy(bytes, debug_abstract + addr - debug_abstract_start, len);
-    return true;
-  }
-
-  if (addr >= debug_data_start && (addr + len) <= (debug_data_start + sizeof(dmdata))) {
-    memcpy(bytes, dmdata + addr - debug_data_start, len);
-    return true;
-  }
+  const auto interval_ptr =
+      std::find_if(debug_memory_regions.begin(), debug_memory_regions.end(),
+                   [addr, len](const auto &range) {
+                     return belongs_to_range(addr, len, range.addr, range.len);
+                   });
 
-  if (addr >= debug_progbuf_start && ((addr + len) <= (debug_progbuf_start + program_buffer_bytes))) {
-    memcpy(bytes, program_buffer + addr - debug_progbuf_start, len);
+  if (interval_ptr != debug_memory_regions.end()) {
+    std::copy_n(std::next(interval_ptr->bytes, addr - interval_ptr->addr), len, bytes);
     return true;
   }
 
@@ -163,6 +196,15 @@ bool debug_module_t::load(reg_t addr, size_t len, uint8_t* bytes)
   return false;
 }
 
+static bool handle_range_store(reg_t input_addr, size_t input_len, const uint8_t *bytes,
+                               reg_t range_addr, size_t range_len, uint8_t *data)
+{
+  if (!belongs_to_range(input_addr, input_len, range_addr, range_len))
+    return false;
+  std::copy_n(bytes, input_len, std::next(data, input_addr - range_addr));
+  return true;
+}
+
 bool debug_module_t::store(reg_t addr, size_t len, const uint8_t* bytes)
 {
   D(
@@ -188,16 +230,11 @@ bool debug_module_t::store(reg_t addr, size_t len, const uint8_t* bytes)
 
   addr = DEBUG_START + addr;
 
-  if (addr >= debug_data_start && (addr + len) <= (debug_data_start + sizeof(dmdata))) {
-    memcpy(dmdata + addr - debug_data_start, bytes, len);
+  if (handle_range_store(addr, len, bytes, debug_data_start, dmdata.size(), dmdata.data()))
     return true;
-  }
-
-  if (addr >= debug_progbuf_start && ((addr + len) <= (debug_progbuf_start + program_buffer_bytes))) {
-    memcpy(program_buffer + addr - debug_progbuf_start, bytes, len);
 
+  if (handle_range_store(addr, len, bytes, debug_progbuf_start, program_buffer_bytes, program_buffer))
     return true;
-  }
 
   if (addr == DEBUG_ROM_HALTED) {
     assert (len == 4);
@@ -283,6 +320,16 @@ unsigned debug_module_t::sb_access_bits()
   return 8 << sbcs.sbaccess;
 }
 
+uint8_t *debug_module_t::get_dmdata_checked(size_t required_size)
+{
+  if(dmdata.size() < required_size) {
+    fprintf(stderr, "dmdata size (%ld) less then required (%ld)\n",
+            dmdata.size(), required_size);
+    exit(1);
+  }
+  return dmdata.data();
+}
+
 void debug_module_t::sb_autoincrement()
 {
   if (!sbcs.autoincrement || !config.max_sba_data_width)
@@ -392,7 +439,8 @@ bool debug_module_t::dmi_read(unsigned address, uint32_t *value)
   D(fprintf(stderr, "dmi_read(0x%x) -> ", address));
   if (address >= DM_DATA0 && address < DM_DATA0 + abstractcs.datacount) {
     unsigned i = address - DM_DATA0;
-    result = read32(dmdata, i);
+    assert(dmdata.size() >= 4);
+    result = read32(get_dmdata_checked(i + 1), i);
     if (abstractcs.busy) {
       result = -1;
       D(fprintf(stderr, "\ndmi_read(0x%02x (data[%d]) -> -1 because abstractcs.busy==true\n", address, i));
@@ -660,6 +708,13 @@ bool debug_module_t::perform_abstract_command()
       return true;
     }
 
+    assert(size < 8);
+    // Check if register fit in dmdata
+    if ((1U << size) > dmdata.size()) {
+      abstractcs.cmderr = CMDERR_NOTSUP;
+      return true;
+    }
+
     unsigned i = 0;
     if (get_field(command, AC_ACCESS_REGISTER_TRANSFER)) {
 
@@ -781,10 +836,11 @@ bool debug_module_t::perform_abstract_command()
         if (write) {
           // Writing V to custom register N will cause future reads of N to
           // return V, reads of N-1 will return V-1, etc.
-          custom_base = read32(dmdata, 0) - custom_number;
+          assert(dmdata.size() >= 4);
+          custom_base = read32(get_dmdata_checked(1), 0) - custom_number;
         } else {
-          write32(dmdata, 0, custom_number + custom_base);
-          write32(dmdata, 1, 0);
+          write32(get_dmdata_checked(1), 0, custom_number + custom_base);
+          write32(get_dmdata_checked(2), 1, 0);
         }
         return true;
 
@@ -832,7 +888,7 @@ bool debug_module_t::dmi_write(unsigned address, uint32_t value)
   if (address >= DM_DATA0 && address < DM_DATA0 + abstractcs.datacount) {
     unsigned i = address - DM_DATA0;
     if (!abstractcs.busy)
-      write32(dmdata, address - DM_DATA0, value);
+      write32(get_dmdata_checked(address - DM_DATA0), address - DM_DATA0, value);
 
     if (abstractcs.busy && abstractcs.cmderr == CMDERR_NONE) {
       abstractcs.cmderr = CMDERR_BUSY;

riscv/debug_module.h

@@ -2,7 +2,7 @@
 #ifndef _RISCV_DEBUG_MODULE_H
 #define _RISCV_DEBUG_MODULE_H
 
-#include <set>
+#include <array>
 #include <vector>
 
 #include "abstract_device.h"
@@ -15,6 +15,7 @@ struct debug_module_config_t {
   // Size of program_buffer in 32-bit words, as exposed to the rest of the
   // world.
   unsigned progbufsize = 2;
+  unsigned datacount = 2;
   unsigned max_sba_data_width = 0;
   bool require_authentication = false;
   unsigned abstract_rti = 0;
@@ -99,6 +100,13 @@ struct hart_debug_state_t {
   uint8_t haltgroup;
 };
 
+// structure to describe mmio region
+struct region_descriptor {
+  reg_t addr;           // 1st addr in a range
+  size_t len;           // range size
+  const uint8_t *bytes; // data
+};
+
 class debug_module_t : public abstract_device_t
 {
   public:
@@ -131,7 +139,6 @@ class debug_module_t : public abstract_device_t
     void proc_reset(unsigned id);
 
   private:
-    static const unsigned datasize = 2;
     debug_module_config_t config;
     // Actual size of the program buffer, which is 1 word bigger than we let on
     // to implement the implicit ebreak at the end.
@@ -150,7 +157,8 @@ class debug_module_t : public abstract_device_t
     uint8_t debug_rom_whereto[4];
     uint8_t debug_abstract[debug_abstract_size * 4];
     uint8_t *program_buffer;
-    uint8_t dmdata[datasize * 4];
+    static constexpr unsigned dmdata_reg_size = 4;
+    std::vector<uint8_t> dmdata;
 
     std::vector<hart_debug_state_t> hart_state;
     uint8_t debug_rom_flags[1024];
@@ -174,6 +182,8 @@ class debug_module_t : public abstract_device_t
 
     unsigned sb_access_bits();
 
+    uint8_t *get_dmdata_checked(size_t required_size);
+
     dmcontrol_t dmcontrol;
     dmstatus_t dmstatus;
     abstractcs_t abstractcs;
@@ -206,6 +216,8 @@ class debug_module_t : public abstract_device_t
     bool hart_available(unsigned hart_id) const;
 
     unsigned sb_read_wait, sb_write_wait;
+
+    std::array<region_descriptor, 6> debug_memory_regions;
 };
 
 #endif

spike_main/spike.cc

@@ -71,6 +71,7 @@ static void help(int exit_code = 1)
   fprintf(stderr, "  --real-time-clint     Increment clint time at real-time rate\n");
   fprintf(stderr, "  --triggers=<n>        Number of supported triggers [default 4]\n");
   fprintf(stderr, "  --dm-progsize=<words> Progsize for the debug module [default 2]\n");
+  fprintf(stderr, "  --dm-datacount=<n>    Number of data registers available for the debug module [default 2]\n");
   fprintf(stderr, "  --dm-sba=<bits>       Debug system bus access supports up to "
       "<bits> wide accesses [default 0]\n");
   fprintf(stderr, "  --dm-auth             Debug module requires debugger to authenticate\n");
@@ -413,6 +414,8 @@ int main(int argc, char** argv)
   });
   parser.option(0, "dm-progsize", 1,
       [&](const char* s){dm_config.progbufsize = atoul_safe(s);});
+  parser.option(0, "dm-datacount", 1,
+      [&](const char* s){dm_config.datacount = atoul_safe(s);});
   parser.option(0, "dm-no-impebreak", 0,
       [&](const char UNUSED *s){dm_config.support_impebreak = false;});
   parser.option(0, "dm-sba", 1,