Initial work for the in-memory disk emulator

8 files changed, 456 insertions, 0 deletions

diff --git a/memdisk/Makefile b/memdisk/Makefile
new file mode 100644
index 00000000..9eb73cf7
--- /dev/null
+++ b/memdisk/Makefile
@@ -0,0 +1,37 @@
+#ident "$Id$"
+## -----------------------------------------------------------------------
+##   
+##   Copyright 2001 H. Peter Anvin - All Rights Reserved
+##
+##   This program is free software; you can redistribute it and/or modify
+##   it under the terms of the GNU General Public License as published by
+##   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+##   Bostom MA 02111-1307, USA; either version 2 of the License, or
+##   (at your option) any later version; incorporated herein by reference.
+##
+## -----------------------------------------------------------------------
+
+CC      = gcc
+CFLAGS  = -g -O2 -fomit-frame-pointer -march=i386 -malign-functions=0 -malign-jumps=0 -malign-loops=0
+LDFLAGS = 
+
+all: e820func.o16 msetup.o16 e820test
+
+clean:
+	rm -f *.o *.s *.o16 *.s16 e820test
+
+%.o16: %.s16
+	as -o $@ $<
+
+%.s16: %.s
+	echo '.code16' | cat - $< > $@
+
+%.s: %.c
+	$(CC) $(CFLAGS) -S -o $@ $<
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c -o $@ $<
+
+e820test: e820func.o msetup.o e820test.o
+	$(CC) $(LDFLAGS) -o $@ $^
+
diff --git a/memdisk/e820.h b/memdisk/e820.h
new file mode 100644
index 00000000..ec261d7f
--- /dev/null
+++ b/memdisk/e820.h
@@ -0,0 +1,30 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * e820.h
+ *
+ * Common routines for e820 memory map management
+ */
+
+#include <stdint.h>
+
+struct e820range {
+  uint64_t start;
+  uint32_t type;
+} __attribute__((packed));
+
+extern struct e820range ranges[];
+extern int nranges;
+
+extern void insertrange(uint64_t, uint64_t, uint32_t);
diff --git a/memdisk/e820data b/memdisk/e820data
new file mode 100644
index 00000000..34ab566d
--- /dev/null
+++ b/memdisk/e820data
@@ -0,0 +1,13 @@
+0000000000000000 000000000009bc00 1
+000000000009bc00 0000000000004400 2
+00000000000e9800 0000000000016800 2
+0000000000100000 0000000006ee0000 1
+0000000006fe0000 000000000000fc00 3
+0000000006fefc00 0000000000000400 4
+0000000006ff0000 0000000000002000 2
+0000000006ff2000 000000000000e000 1
+0000000007000000 0000000000100000 2
+00000000fff00000 0000000000100000 2
+
+0000000000586000 0000000000168000 2
+000000000009ba00 0000000000000200 2
diff --git a/memdisk/e820func.c b/memdisk/e820func.c
new file mode 100644
index 00000000..72e1bf80
--- /dev/null
+++ b/memdisk/e820func.c
@@ -0,0 +1,96 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * e820func.c
+ *
+ * E820 range database manager
+ */
+
+#include <stdint.h>
+#include "e820.h"
+
+#define MAXRANGES	64
+/* All of memory starts out as one range of "indeterminate" type */
+struct e820range ranges[MAXRANGES] = { { 0ULL, 0 }, { 0ULL, (uint32_t)-1 } };
+int nranges = 1;
+
+static void insertrange_at(int where, uint64_t start, uint32_t type)
+{
+  int i;
+
+  for ( i = nranges ; i > where ; i-- )
+    ranges[i] = ranges[i-1];
+  
+  ranges[where].start = start;
+  ranges[where].type  = type;
+
+  nranges++;
+  ranges[nranges].start = 0ULL;
+  ranges[nranges].type  = (uint32_t)-1;
+}
+
+void insertrange(uint64_t start, uint64_t len, uint32_t type)
+{
+  uint64_t newstart, last;
+  uint32_t oldtype;
+  int i, j;
+
+  /* Remove this to make len == 0 mean all of memory */
+  if ( len == 0 )
+    return;			/* Nothing to insert */
+  
+  last = start+len-1;		/* May roll over */
+
+  i = 0;
+  oldtype = -2;
+  while ( start > ranges[i].start && ranges[i].type != -1 ) {
+    oldtype = ranges[i].type;
+    i++;
+  }
+
+  /* Consider the replacement policy.  This current one is "overwrite." */
+
+  if ( start < ranges[i].start || ranges[i].type == -1 )
+    insertrange_at(i++, start, type);
+
+  while ( i == 0 || last > ranges[i].start-1 ) {
+    oldtype = ranges[i].type;
+    ranges[i].type = type;
+    i++;
+  }
+
+  if ( last < ranges[i].start-1 )
+    insertrange_at(i, last+1, oldtype);
+
+  /* Now the map is correct, but quite possibly not optimal.  Scan the
+     map for ranges which are redundant and remove them. */
+  i = j = 1;
+  oldtype = ranges[0].type;
+  while ( i < nranges ) {
+    if ( ranges[i].type == oldtype ) {
+      i++;
+    } else {
+      oldtype = ranges[i].type;
+      if ( i != j )
+	ranges[j] = ranges[i];
+      i++; j++;
+    }
+  }
+
+  if ( i != j ) {
+    ranges[j] = ranges[i];	/* Termination sentinel copy */
+    nranges -= (i-j);
+  }
+}
+
diff --git a/memdisk/e820test.c b/memdisk/e820test.c
new file mode 100644
index 00000000..2717fdcd
--- /dev/null
+++ b/memdisk/e820test.c
@@ -0,0 +1,74 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * e820hack.c
+ *
+ * Test of INT 15:E820 canonicalization/manipulation routine
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+#include "e820.h"
+
+extern void parse_mem(void);
+extern uint32_t dos_mem, low_mem, high_mem;
+
+void printranges(void) {
+  int i;
+
+  for ( i = 0 ; i < nranges ; i++ ) {
+    printf("%016Lx %016Lx %d\n",
+	   ranges[i].start,
+	   ranges[i+1].start - ranges[i].start,
+	   ranges[i].type);
+  }
+}
+
+int main(int argc, char *argv[])
+{
+  uint64_t start, len;
+  uint32_t type;
+
+  printranges();
+
+  while ( scanf("%Lx %Lx %d", &start, &len, &type) == 3 ) {
+    putchar('\n'); 
+    printf("%016Lx %016Lx %d <-\n", start, len, type);
+    putchar('\n'); 
+    insertrange(start, len, type);
+    printranges(); 
+ }
+
+  parse_mem();
+
+  putchar('\n');
+  printf("DOS  mem = %#10x (%u K)\n", dos_mem, dos_mem >> 10);
+  printf("Low  mem = %#10x (%u K)\n", low_mem, low_mem >> 10);
+  printf("High mem = %#10x (%u K)\n", high_mem, high_mem >> 10);
+  putchar('\n');
+
+  /* Now, steal a chunk (2K) of DOS memory and make sure it registered OK */
+  insertrange(dos_mem-2048, 2048, 2); /* Type 2 = reserved */
+  
+  printranges();
+  parse_mem();
+
+  putchar('\n');
+  printf("DOS  mem = %#10x (%u K)\n", dos_mem, dos_mem >> 10);
+  printf("Low  mem = %#10x (%u K)\n", low_mem, low_mem >> 10);
+  printf("High mem = %#10x (%u K)\n", high_mem, high_mem >> 10);
+  putchar('\n');
+
+  return 0;
+}
diff --git a/memdisk/msetup.c b/memdisk/msetup.c
new file mode 100644
index 00000000..c37169be
--- /dev/null
+++ b/memdisk/msetup.c
@@ -0,0 +1,183 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Bostom MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * msetup.c
+ *
+ * Initialization code for memory-based disk
+ */
+
+#include <stdint.h>
+#include "e820.h"
+
+static inline int get_e820(void)
+{
+  struct e820_info {
+    uint64_t base;
+    uint64_t len;
+    uint32_t type;
+  } __attribute__((packed));
+  struct e820_info buf;
+  uint32_t lastptr = 0;
+  int copied;
+  int range_count;
+  
+  do {
+    asm volatile("int $0x15 ; "
+		 "jc 1f ; "
+		 "cmpl $0x534d4150, %%eax ; "
+		 "je 2f\n"
+		 "1:\n\t"
+		 "xorl %%ecx, %%ecx\n"
+		 "2:"
+		 : "=c" (copied), "=&b" (lastptr)
+		 : "a" (0x0000e820), "d" (0x534d4150),
+		 "c" (20), "D" (&buf)
+		 : "esi", "ebp");
+
+    if ( copied < 20 )
+      break;
+
+    insertrange(buf.base, buf.len, buf.type);
+    range_count++;
+
+  } while ( lastptr );
+
+  return !range_count;
+}
+
+static inline void get_dos_mem(void)
+{
+  uint16_t dos_kb;
+
+  asm volatile("int $0x12" : "=a" (dos_kb)
+	       :: "ebx", "ecx", "edx", "esi", "edi", "ebp");
+  
+  insertrange(0, (uint64_t)((uint32_t)dos_kb << 10), 1);
+}
+
+static inline int get_e881(void)
+{
+  uint32_t low_mem;
+  uint32_t high_mem;
+  uint8_t err;
+
+  asm volatile("movw $0xe881, %%ax ; "
+	       "int $0x15 ; "
+	       "setc %2"
+	       : "=a" (low_mem), "=b" (high_mem), "=d" (err)
+	       :: "ecx", "esi", "edi", "ebp");
+
+  if ( !err ) {
+    if ( low_mem ) {
+      insertrange(0x100000, (uint64_t)low_mem << 10, 1);
+    }
+    if ( high_mem ) {
+      insertrange(0x1000000, (uint64_t)high_mem << 16, 1);
+    }
+  }
+
+  return err;
+}
+
+static inline int get_e801(void)
+{
+  uint16_t low_mem;
+  uint16_t high_mem;
+  uint8_t err;
+
+  asm volatile("movw $0xe801, %%ax ; "
+	       "int $0x15 ; "
+	       "setc %2"
+	       : "=a" (low_mem), "=b" (high_mem), "=d" (err)
+	       :: "ecx", "esi", "edi", "ebp");
+
+  if ( !err ) {
+    if ( low_mem ) {
+      insertrange(0x100000, (uint64_t)((uint32_t)low_mem << 10), 1);
+    }
+    if ( high_mem ) {
+      insertrange(0x1000000, (uint64_t)((uint32_t)high_mem << 16), 1);
+    }
+  }
+
+  return err;
+}
+
+static inline int get_88(void)
+{
+  uint16_t low_mem;
+  uint8_t err;
+
+  asm volatile("movb $0x88,%%ah ; "
+	       "int $0x15 ; "
+	       "setc %1"
+	       : "=a" (low_mem), "=d" (err)
+	       :: "ebx", "ecx", "esi", "edi", "ebp");
+
+  if ( !err ) {
+    if ( low_mem ) {
+      insertrange(0x100000, (uint64_t)((uint32_t)low_mem << 10), 1);
+    }
+  }
+
+  return err;
+}
+
+uint32_t dos_mem  = 0;		/* 0-1MB */
+uint32_t low_mem  = 0;		/* 1-16MB */
+uint32_t high_mem = 0;		/* 16+ MB */
+
+void get_mem(void)
+{
+  if ( get_e820() ) {
+    get_dos_mem();
+    if ( get_e881() ) {
+      if ( get_e801() ) {
+	if ( get_88() ) {
+	  /* Running out of ideas here... */
+	}
+      }
+    }
+  }
+}
+
+void parse_mem(void)
+{
+  struct e820range *ep;
+
+  /* Derive "dos mem", "high mem", and "low mem" from the range array */
+  for ( ep = ranges ; ep->type != -1 ; ep++ ) {
+    if ( ep->type == 1 ) {
+      /* Only look at memory ranges */
+      if ( ep->start == 0 ) {
+	if ( ep[1].start > 0x100000 )
+	  dos_mem = 0x100000;
+	else
+	  dos_mem = ep[1].start;
+      }
+      if ( ep->start <= 0x100000 && ep[1].start > 0x100000 ) {
+	if ( ep[1].start > 0x1000000 )
+	  low_mem = 0x1000000 - ep->start;
+	else
+	  low_mem = ep[1].start - ep->start;
+      }
+      if ( ep->start <= 0x1000000 && ep[1].start > 0x1000000 ) {
+	if ( ep[1].start > 0x100000000 )
+	  high_mem = 0x100000000 - ep->start;
+	else
+	  high_mem = ep[1].start - ep->start;
+      }
+    }
+  }
+}
diff --git a/memdisk/testdata1 b/memdisk/testdata1
new file mode 100644
index 00000000..34ab566d
--- /dev/null
+++ b/memdisk/testdata1
@@ -0,0 +1,13 @@
+0000000000000000 000000000009bc00 1
+000000000009bc00 0000000000004400 2
+00000000000e9800 0000000000016800 2
+0000000000100000 0000000006ee0000 1
+0000000006fe0000 000000000000fc00 3
+0000000006fefc00 0000000000000400 4
+0000000006ff0000 0000000000002000 2
+0000000006ff2000 000000000000e000 1
+0000000007000000 0000000000100000 2
+00000000fff00000 0000000000100000 2
+
+0000000000586000 0000000000168000 2
+000000000009ba00 0000000000000200 2
diff --git a/memdisk/testdata2 b/memdisk/testdata2
new file mode 100644
index 00000000..8bec5bfc
--- /dev/null
+++ b/memdisk/testdata2
@@ -0,0 +1,10 @@
+0000000000000000 000000000009bc00 1
+000000000009bc00 0000000000004400 2
+00000000000e9800 0000000000016800 2
+0000000000100000 0000000006ee0000 1
+0000000006fe0000 000000000000fc00 3
+0000000006fefc00 0000000000000400 4
+0000000006ff0000 0000000000002000 2
+0000000006ff2000 000000000000e000 1
+0000000007000000 0000000000100000 2
+00000000fff00000 0000000000100000 2