[Glacier][Zion] Add a fix sized string builder to allow non-alloc debug.

lib/glacier/string/str_format.h

@@ -59,10 +59,16 @@ void StrFormatInternal(StringBuilder& builder, StringView format, T value,
 }
 
 template <typename... Args>
-StringBuilder StrFormat(StringView format, Args... args) {
-  StringBuilder builder;
+String StrFormat(StringView format, Args... args) {
+  VariableStringBuilder builder;
+  StrFormatInternal(builder, format, args...);
+  return builder.ToString();
+}
+
+template <typename... Args>
+void StrFormatIntoBuffer(StringBuilder& builder, StringView format,
+                         Args... args) {
   StrFormatInternal(builder, format, args...);
-  return glcr::Move(builder);
 }
 
 }  // namespace glcr

lib/glacier/string/string_builder.cpp

@@ -2,23 +2,52 @@
 
 namespace glcr {
 
-void StringBuilder::PushBack(const StringView& str) {
-  if (capacity() < size() + str.size()) {
-    uint64_t new_capacity = capacity() == 0 ? 1 : capacity() * 2;
+uint64_t VariableStringBuilder::size() const { return data_.size(); }
+
+void VariableStringBuilder::PushBack(const StringView& str) {
+  if (data_.capacity() < size() + str.size()) {
+    uint64_t new_capacity = data_.capacity() == 0 ? 1 : data_.capacity() * 2;
     while (new_capacity < size() + str.size()) {
       new_capacity *= 2;
     }
-    Resize(new_capacity);
+    data_.Resize(new_capacity);
   }
   for (uint64_t i = 0; i < str.size(); i++) {
-    Vector<char>::PushBack(str[i]);
+    data_.PushBack(str[i]);
   }
 }
 
-String StringBuilder::ToString() const { return String(RawPtr(), size()); }
+void VariableStringBuilder::PushBack(const char str) { data_.PushBack(str); }
 
-StringBuilder::operator StringView() const {
-  return StringView(RawPtr(), size());
+String VariableStringBuilder::ToString() const {
+  return String(data_.RawPtr(), size());
+}
+
+VariableStringBuilder::operator StringView() const {
+  return StringView(data_.RawPtr(), size());
+}
+
+void FixedStringBuilder::PushBack(const StringView& str) {
+  for (uint64_t i = 0; i < str.size(); i++) {
+    PushBack(str[i]);
+  }
+}
+
+void FixedStringBuilder::PushBack(const char str) {
+  if (size_ >= capacity_) {
+    // Somewhat random sequence of characters to show that we've overrun the
+    // buffer.
+    buffer_[capacity_ - 1] = '>';
+    buffer_[capacity_ - 2] = '!';
+  } else {
+    buffer_[size_++] = str;
+  }
+}
+
+String FixedStringBuilder::ToString() const { return String(buffer_, size_); }
+
+FixedStringBuilder::operator StringView() const {
+  return StringView(buffer_, size_);
 }
 
 }  // namespace glcr

lib/glacier/string/string_builder.h

@@ -6,21 +6,64 @@
 
 namespace glcr {
 
-class StringBuilder : public Vector<char> {
+class StringBuilder {
  public:
-  StringBuilder() : Vector<char>() {}
-  StringBuilder(const StringBuilder&) = delete;
-  StringBuilder(StringBuilder&& str) : Vector<char>(Move(str)) {}
+  virtual uint64_t size() const = 0;
+  virtual void PushBack(const StringView& str) = 0;
+  virtual void PushBack(const char str) = 0;
 
-  void PushBack(const StringView& str);
-  using Vector<char>::PushBack;
+  virtual String ToString() const = 0;
 
-  String ToString() const;
+  virtual operator StringView() const = 0;
+};
+
+class VariableStringBuilder : public StringBuilder {
+ public:
+  VariableStringBuilder() = default;
+  VariableStringBuilder(const VariableStringBuilder&) = delete;
+  VariableStringBuilder(VariableStringBuilder&&) = default;
+
+  ~VariableStringBuilder() = default;
+
+  virtual uint64_t size() const override;
+
+  virtual void PushBack(const StringView& str) override;
+  virtual void PushBack(const char str) override;
+
+  virtual String ToString() const override;
 
   // Note that this could become invalidated
   // at any time if more characters are pushed
   // onto the builder.
-  operator StringView() const;
+  virtual operator StringView() const override;
+
+ private:
+  Vector<char> data_;
+};
+
+class FixedStringBuilder : public StringBuilder {
+ public:
+  FixedStringBuilder() = delete;
+  FixedStringBuilder(const FixedStringBuilder&) = delete;
+  FixedStringBuilder(FixedStringBuilder&&) = delete;
+  ~FixedStringBuilder() = default;
+
+  FixedStringBuilder(char* buffer, uint64_t size)
+      : buffer_(buffer), capacity_(size), size_(0) {}
+
+  virtual uint64_t size() const override { return size_; }
+
+  virtual void PushBack(const StringView& str) override;
+  virtual void PushBack(const char str) override;
+
+  virtual String ToString() const override;
+
+  virtual operator StringView() const override;
+
+ private:
+  char* buffer_;
+  uint64_t capacity_;
+  uint64_t size_;
 };
 
 }  // namespace glcr

lib/mammoth/include/mammoth/debug.h

@@ -6,7 +6,7 @@
 #include <ztypes.h>
 
 // TODO: Take StringView here instead.
-void dbgln(const glcr::StringBuilder& builder);
+void dbgln(const glcr::String& string);
 
 template <typename... Args>
 void dbgln(const glcr::StringView& fmt, Args... args) {

lib/mammoth/src/debug.cpp

@@ -3,10 +3,7 @@
 #include <glacier/status/error.h>
 #include <zcall.h>
 
-void dbgln(const glcr::StringBuilder& builder) {
-  glcr::String str = builder.ToString();
-  (void)ZDebug(str.cstr());
-}
+void dbgln(const glcr::String& string) { (void)ZDebug(string.cstr()); }
 
 void check(uint64_t code) {
   switch (code) {

zion/debug/debug.cpp

@@ -27,59 +27,6 @@ void dbg(const glcr::StringView& str) {
   }
 }
 
-void U64ToStr(uint64_t u, char* str) {
-  uint64_t len = 0;
-  uint64_t u2 = u;
-  while (u2 != 0) {
-    len++;
-    u2 /= 10;
-  }
-
-  if (len == 0) {
-    len = 1;
-  }
-
-  str[len] = '\0';
-
-  for (int64_t i = len - 1; i >= 0; i--) {
-    str[i] = (u % 10) + '0';
-    u /= 10;
-  }
-}
-
-void HexToStr(uint64_t u, char* str) {
-  uint64_t len = 0;
-  uint64_t u2 = u;
-  while (u2 != 0) {
-    len++;
-    u2 /= 16;
-  }
-
-  if (len == 0) {
-    len = 1;
-  }
-
-  len += 2;
-  str[0] = '0';
-  str[1] = 'x';
-  str[len] = '\0';
-  const char* hex = "0123456789ABCDEF";
-  for (uint64_t i = len - 1; i > 1; i--) {
-    str[i] = hex[u & 0xF];
-    u >>= 4;
-  }
-}
-
-void MemToStr(uint64_t u, char* str) {
-  str[0] = '0';
-  str[1] = 'x';
-  const char* hex = "0123456789ABCDEF";
-  for (uint64_t i = 0; i < 16; i++) {
-    str[17 - i] = hex[(u >> (i * 4)) & 0xF];
-  }
-  str[18] = '\0';
-}
-
 void AddProcPrefix() {
   if (gScheduler != nullptr) {
     auto t = gScheduler->CurrentThread();
@@ -87,90 +34,15 @@ void AddProcPrefix() {
   }
 }
 
-void dbg_internal(const char* fmt, va_list args) {
-  for (; *fmt != '\0'; fmt++) {
-    if (*fmt != '%') {
-      dbgputchar(*fmt);
-      continue;
-    }
-    fmt++;
-    switch (*fmt) {
-      case '%':
-        dbgputchar('%');
-        break;
-      case 's': {
-        char* str = va_arg(args, char*);
-        dbgcstr(str);
-        break;
-      }
-      case 'c': {
-        char c = va_arg(args, int);
-        dbgputchar(c);
-        break;
-      }
-      case 'u': {
-        uint64_t u = va_arg(args, uint64_t);
-        char str[21];
-        U64ToStr(u, str);
-        dbgcstr(str);
-        break;
-      }
-      case 'x': {
-        uint64_t u = va_arg(args, uint64_t);
-        char str[19];
-        HexToStr(u, str);
-        dbgcstr(str);
-        break;
-      }
-      case 'm': {
-        uint64_t u = va_arg(args, uint64_t);
-        char str[19];
-        MemToStr(u, str);
-        dbgcstr(str);
-        break;
-      }
-      default: {
-        panic("Bad format char: %c", *fmt);
-      }
-    }
-  }
-}
-
 }  // namespace
 
-void early_dbgln(const char* str) { dbgcstr(str); }
+void early_dbgln(const char* str) {
+  dbgcstr(str);
+  dbgcstr("\n");
+}
 
 void dbgln(const glcr::StringView& str) {
   AddProcPrefix();
   dbg(str);
   dbg("\n");
 }
-
-void dbg(const char* fmt, ...) {
-  va_list arg;
-  va_start(arg, fmt);
-  dbg_internal(fmt, arg);
-  va_end(arg);
-}
-
-void dbgln(const char* fmt, ...) {
-  AddProcPrefix();
-  va_list arg;
-  va_start(arg, fmt);
-  dbg_internal(fmt, arg);
-  va_end(arg);
-  dbgputchar('\n');
-}
-
-void panic(const char* fmt, ...) {
-  asm volatile("cli");
-  AddProcPrefix();
-  va_list arg;
-  va_start(arg, fmt);
-  dbg_internal(fmt, arg);
-  va_end(arg);
-  dbgputchar('\n');
-  dbgln("PANIC");
-  while (1)
-    ;
-}

zion/debug/debug.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <glacier/string/str_format.h>
+#include <glacier/string/string_builder.h>
 #include <stdarg.h>
 
 #include "include/ztypes.h"
@@ -11,15 +12,32 @@ void early_dbgln(const char* str);
 
 void dbgln(const glcr::StringView& str);
 
+// TODO: Write a version of StrFormat that
+// accepts a fix-sized buffer for output
+// to use in the kernel. That way we make
+// dbgln and panic calls without allocation.
+// Optionally, add a dbgln_unbounded method for
+// things like the Debug syscall where the formatted
+// string may be fairly large.
+
 template <typename... Args>
 void dbgln(const char* str, Args... args) {
+  char buffer[256];
+  glcr::FixedStringBuilder builder(buffer, 256);
+  glcr::StrFormatIntoBuffer(builder, str, args...);
+  dbgln(builder);
+}
+
+template <typename... Args>
+void dbgln_large(const char* str, Args... args) {
   dbgln(glcr::StrFormat(str, args...));
 }
 
 template <typename... Args>
 void panic(const char* str, Args... args) {
-  dbgln(glcr::StrFormat(str, args...));
+  dbgln(str, args...);
   dbgln("PANIC");
+  asm volatile("hlt;");
 }
 
 #define UNREACHABLE                                \

zion/memory/physical_memory.cpp

@@ -36,9 +36,6 @@ class PhysicalMemoryManager {
     const limine_memmap_response& memmap = boot::GetMemoryMap();
     for (uint64_t i = 0; i < memmap.entry_count; i++) {
       const limine_memmap_entry& entry = *memmap.entries[i];
-#if K_PHYS_DEBUG
-      dbgln("Region({}) at {x}:{x}", entry.type, entry.base, entry.length);
-#endif
       if (entry.type == 0) {
         uint64_t base = entry.base;
         uint64_t size = entry.length;
@@ -155,6 +152,38 @@ void InitBootstrapPageAllocation() {
 
 void InitPhysicalMemoryManager() { gPmm = new PhysicalMemoryManager(); }
 
+glcr::StringView MemoryRegionStr(uint64_t type) {
+  switch (type) {
+    case LIMINE_MEMMAP_USABLE:
+      return "USABLE";
+    case LIMINE_MEMMAP_RESERVED:
+      return "RESRVD";
+    case LIMINE_MEMMAP_ACPI_RECLAIMABLE:
+      return "ACPIREC";
+    case LIMINE_MEMMAP_ACPI_NVS:
+      return "ACPINVS";
+    case LIMINE_MEMMAP_BAD_MEMORY:
+      return "BADMEM";
+    case LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE:
+      return "LIMINE";
+    case LIMINE_MEMMAP_KERNEL_AND_MODULES:
+      return "KERNEL";
+    case LIMINE_MEMMAP_FRAMEBUFFER:
+      return "FRMBFR";
+    default:
+      return "UNKNWN";
+  }
+}
+
+void DumpRegions() {
+  const limine_memmap_response& memmap = boot::GetMemoryMap();
+  for (uint64_t i = 0; i < memmap.entry_count; i++) {
+    const limine_memmap_entry& entry = *memmap.entries[i];
+    dbgln("Region({}) at {x}:{x} ({x})", MemoryRegionStr(entry.type),
+          entry.base, entry.base + entry.length, entry.length);
+  }
+}
+
 uint64_t AllocatePage() {
   if (gPmm != nullptr) {
     return gPmm->AllocatePage();
@@ -164,7 +193,7 @@ uint64_t AllocatePage() {
   }
 
 #if K_PHYS_DEBUG
-  dbgln("[PMM] Boostrap Alloc!");
+  early_dbgln("[PMM] Boostrap Alloc!");
 #endif
 
   uint64_t page = gBootstrap.next_page;

zion/memory/physical_memory.h

@@ -13,6 +13,8 @@ void InitBootstrapPageAllocation();
 // Initializes the main physical memory manager.
 void InitPhysicalMemoryManager();
 
+void DumpRegions();
+
 uint64_t AllocatePage();
 uint64_t AllocateAndZeroPage();
 

zion/syscall/debug.cpp

@@ -5,6 +5,6 @@
 #include "debug/debug.h"
 
 z_err_t Debug(ZDebugReq* req) {
-  dbgln("[Debug] {}", req->message);
+  dbgln_large("[Debug] {}", req->message);
   return glcr::OK;
 }

zion/zion.cpp

@@ -26,6 +26,7 @@ extern "C" void zion() {
   KernelHeap heap(0xFFFFFFFF'40000000, 0xFFFFFFFF'80000000);
   phys_mem::InitPhysicalMemoryManager();
   heap.InitializeSlabAllocators();
+  phys_mem::DumpRegions();
 
   dbgln("[boot] Memory allocations available now.");