Ticket #4399: mtrr_uncachable.diff

src/system/boot/platform/bios_ia32/video.cpp

@@ -833 +833 @@
     if (lastBase != 0
         && (lastBase != gKernelArgs.frame_buffer.physical_buffer.start
             || lastSize < gKernelArgs.frame_buffer.physical_buffer.size)) {
-        mmu_free((void *)sFrameBuffer, lastSize);
+        mmu_free((void *)lastBase, lastSize);
         lastBase = 0;
     }
     if (lastBase == 0) {

src/system/boot/platform/bios_ia32/cpu.h

@@ -13 +13 @@
 extern "C" {
 #endif
 
+extern void mtrr_dump(void);
 extern void cpu_init(void);
 
 #ifdef __cplusplus

src/system/boot/platform/bios_ia32/console.cpp

@@ -71 +71 @@
         return bufferSize;
 
     for (uint32 i = 0; i < bufferSize; i++) {
-        if (string[0] == '\n')
+        if (string[0] == '\n') {
             sScreenOffset += sScreenWidth - (sScreenOffset % sScreenWidth);
-        else
+            spin(1 * 1000 * 1000);
+        } else
             sScreenBase[sScreenOffset++] = sColor | string[0];
 
         if (sScreenOffset >= sScreenWidth * sScreenHeight)

src/system/boot/platform/bios_ia32/cpu.cpp

@@ -251 +251 @@
 }
 
 
+static uint64
+read_msr(uint32 msr)
+{
+    uint32 low, high;
+    asm volatile ("rdmsr" : "=a"(low), "=d"(high) : "c"(msr));
+    return ((uint64)high << 32) | low;
+}
+
+
+static void
+write_msr(uint32 msr, uint64 value)
+{
+    uint32 low = (uint32)value;
+    uint32 high = (uint32)(value >> 32);
+    asm volatile ("wrmsr" : : "a"(low), "d"(high), "c"(msr));
+}
+
+
+static const char *
+mtrr_type_to_string(uint8 type)
+{
+    switch (type) {
+        case 0:
+            return "uncacheable";
+        case 1:
+            return "write combining";
+        case 4:
+            return "write-through";
+        case 5:
+            return "write-protected";
+        case 6:
+            return "write-back";
+        default:
+            return "reserved";
+    }
+}
+
+
+static bool
+get_mtrr(uint32 index, uint64 *_base, uint64 *_length, uint8 *_type)
+{
+    uint64 mask = read_msr(0x201 + index * 2);
+    if ((mask & (1 << 11)) == 0)
+        return false;
+
+    uint64 base = read_msr(0x200 + index * 2);
+
+    *_base = base & ~(B_PAGE_SIZE - 1);
+    *_length = (~mask & ((1ULL << 36) - 1)) + B_PAGE_SIZE;
+    *_type = base & 0xff;
+
+    return true;
+}
+
+
 extern "C" void
+mtrr_dump()
+{
+    uint32 count = (read_msr(0xfe) & 0xff);
+    dprintf("mtrr: %lu variable ranges\n", count);
+
+    uint64 defaultType = read_msr(0x2ff);
+    dprintf("mtrr: default type: 0x%llx (%s, variable %sabled, fixed %sabled)\n",
+        defaultType, mtrr_type_to_string(defaultType),
+        (defaultType & (1 << 11)) != 0 ? "en" : "dis",
+        (defaultType & (1 << 10)) != 0 ? "en" : "dis");
+
+    for (uint32 i = 0; i < count; i++) {
+        uint64 base, length;
+        uint8 type;
+        if (get_mtrr(i, &base, &length, &type)) {
+            dprintf("mtrr: entry %lu: base: 0x%llx; length: 0x%llx; type: %u %s\n",
+                i, base, length, type, mtrr_type_to_string(type));
+        } else
+            dprintf("mtrr: entry %lu: empty\n", i);
+    }
+
+    // set default to uncachable
+    write_msr(0x2ff, read_msr(0x2ff) & ~0xff);
+}
+
+
+extern "C" void
 cpu_init()
 {
     if (check_cpu_features() != B_OK)

src/system/boot/platform/bios_ia32/start.c

@@ -138 +138 @@
     //if (sBootOptions & BOOT_OPTION_DEBUG_OUTPUT)
         serial_enable();
 
+    mtrr_dump();
     apm_init();
     acpi_init();
     smp_init();