Support "extended attributes" for INT 15h, AX=E820h

Some blithering idiot thought it was a good idea to introduce
"extended attributes" for INT 15h, AX=E820h, and in doing so, breaking
compatibility with ALL E820 users out there.  F*cking morons.
Implement handling of extended attributes in:

- e820 parsing in the core
- e820 parsing in libcom32
- e820 parsing *and proxying* in memdisk

The latter is the really painful one.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

7 files changed, 87 insertions, 54 deletions

diff --git a/memdisk/e820.h b/memdisk/e820.h
index 04b44484..429b98c2 100644
--- a/memdisk/e820.h
+++ b/memdisk/e820.h
@@ -21,6 +21,7 @@
 struct e820range {
   uint64_t start;
   uint32_t type;
+  uint32_t extattr;
 } __attribute__((packed));
 
 extern struct e820range ranges[];
@@ -28,6 +29,6 @@ extern int nranges;
 extern uint32_t dos_mem, low_mem, high_mem;
 
 extern void e820map_init(void);
-extern void insertrange(uint64_t, uint64_t, uint32_t);
+extern void insertrange(uint64_t, uint64_t, uint32_t, uint32_t);
 extern void get_mem(void);
 extern void parse_mem(void);
diff --git a/memdisk/e820data b/memdisk/e820data
index 34ab566d..14320aac 100644
--- a/memdisk/e820data
+++ b/memdisk/e820data
@@ -1,13 +1,15 @@
-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
+0000000000000000 000000000009bc00 1 1
+000000000009bc00 0000000000004400 2 1
+00000000000e9800 0000000000016800 2 1
+00000000000e9800 000000000000b400 2 1
+00000000000f5000 000000000000b000 2 9
+0000000000100000 0000000006ee0000 1 1
+0000000006fe0000 000000000000fc00 3 1
+0000000006fefc00 0000000000000400 4 1
+0000000006ff0000 0000000000002000 2 1
+0000000006ff2000 000000000000e000 1 1
+0000000007000000 0000000000100000 2 1
+00000000fff00000 0000000000100000 2 1
 
-0000000000586000 0000000000168000 2
-000000000009ba00 0000000000000200 2
+0000000000586000 0000000000168000 2 1
+000000000009ba00 0000000000000200 2 1
diff --git a/memdisk/e820func.c b/memdisk/e820func.c
index 577469b7..a6896745 100644
--- a/memdisk/e820func.c
+++ b/memdisk/e820func.c
@@ -17,7 +17,11 @@
  */
 
 #include <stdint.h>
+#ifdef TEST
+#include <string.h>
+#else
 #include "memdisk.h"		/* For memset() */
+#endif
 #include "e820.h"
 
 #define MAXRANGES	1024
@@ -33,25 +37,28 @@ void e820map_init(void)
   ranges[1].type = -1;
 }
 
-static void insertrange_at(int where, uint64_t start, uint32_t type)
+static void insertrange_at(int where, uint64_t start,
+			   uint32_t type, uint32_t extattr)
 {
   int i;
 
   for ( i = nranges ; i > where ; i-- )
     ranges[i] = ranges[i-1];
 
-  ranges[where].start = start;
-  ranges[where].type  = type;
+  ranges[where].start   = start;
+  ranges[where].type    = type;
+  ranges[where].extattr = extattr;
 
   nranges++;
-  ranges[nranges].start = 0ULL;
-  ranges[nranges].type  = (uint32_t)-1;
+  ranges[nranges].start   = 0ULL;
+  ranges[nranges].type    = (uint32_t)-1;
+  ranges[nranges].extattr = 0;
 }
 
-void insertrange(uint64_t start, uint64_t len, uint32_t type)
+void insertrange(uint64_t start, uint64_t len, uint32_t type, uint32_t extattr)
 {
   uint64_t last;
-  uint32_t oldtype;
+  uint32_t oldtype, oldattr;
   int i, j;
 
   /* Remove this to make len == 0 mean all of memory */
@@ -61,35 +68,42 @@ void insertrange(uint64_t start, uint64_t len, uint32_t type)
   last = start+len-1;		/* May roll over */
 
   i = 0;
-  oldtype = -2;
-  while ( start > ranges[i].start && ranges[i].type != -1 ) {
+  oldtype = -2U;
+  oldattr = 0;
+  while ( start > ranges[i].start && ranges[i].type != -1U ) {
     oldtype = ranges[i].type;
+    oldattr = ranges[i].extattr;
     i++;
   }
 
   /* Consider the replacement policy.  This current one is "overwrite." */
 
-  if ( start < ranges[i].start || ranges[i].type == -1 )
-    insertrange_at(i++, start, type);
+  if ( start < ranges[i].start || ranges[i].type == -1U )
+    insertrange_at(i++, start, type, extattr);
 
   while ( i == 0 || last > ranges[i].start-1 ) {
     oldtype = ranges[i].type;
-    ranges[i].type = type;
+    oldattr = ranges[i].extattr;
+    ranges[i].type    = type;
+    ranges[i].extattr = extattr;
     i++;
   }
 
   if ( last < ranges[i].start-1 )
-    insertrange_at(i, last+1, oldtype);
+    insertrange_at(i, last+1, oldtype, oldattr);
 
   /* 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;
+  oldattr = ranges[0].extattr;
   while ( i < nranges ) {
-    if ( ranges[i].type == oldtype ) {
+    if ( ranges[i].type == oldtype &&
+	 ranges[i].extattr == oldattr ) {
       i++;
     } else {
       oldtype = ranges[i].type;
+      oldattr = ranges[i].extattr;
       if ( i != j )
 	ranges[j] = ranges[i];
       i++; j++;
diff --git a/memdisk/e820test.c b/memdisk/e820test.c
index c2be7437..41fee007 100644
--- a/memdisk/e820test.c
+++ b/memdisk/e820test.c
@@ -36,17 +36,17 @@ void printranges(void) {
   int i;
 
   for ( i = 0 ; i < nranges ; i++ ) {
-    printf("%016llx %016llx %d\n",
+    printf("%016llx %016llx %d %x\n",
 	   ranges[i].start,
 	   ranges[i+1].start - ranges[i].start,
-	   ranges[i].type);
+	   ranges[i].type, ranges[i].extattr);
   }
 }
 
 int main(void)
 {
   uint64_t start, len;
-  uint32_t type;
+  uint32_t type, extattr;
   char line[BUFSIZ], *p;
 
   e820map_init();
@@ -55,11 +55,12 @@ int main(void)
   while ( fgets(line, BUFSIZ, stdin) ) {
     p = strchr(line, ':');
     p = p ? p+1 : line;
-    if ( sscanf(p, " %llx %llx %d", &start, &len, &type) == 3 ) {
+    extattr = 1;
+    if ( sscanf(p, " %llx %llx %d %x", &start, &len, &type, &extattr) >= 3 ) {
       putchar('\n');
-      printf("%016llx %016llx %d <-\n", start, len, type);
+      printf("%016llx %016llx %d %x <-\n", start, len, type, extattr);
       putchar('\n');
-      insertrange(start, len, type);
+      insertrange(start, len, type, extattr);
       printranges();
     }
   }
@@ -73,7 +74,7 @@ int main(void)
   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 */
+  insertrange(dos_mem-2048, 2048, 2, 1); /* Type 2 = reserved */
 
   printranges();
   parse_mem();
diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm
index eb4370ab..47b55fce 100644
--- a/memdisk/memdisk.asm
+++ b/memdisk/memdisk.asm
@@ -530,38 +530,46 @@ EDDEject:
 ;
 int15_e820:
 		cmp edx,534D4150h	; "SMAP"
-		jne near oldint15
+		jne oldint15
 		cmp ecx,20		; Need 20 bytes
 		jb err86
 		push ds
 		push cs
 		pop ds
+		push edx		; "SMAP"
 		and ebx,ebx
 		jne .renew
 		mov ebx,E820Table
 .renew:
-		add bx,12		; Advance to next
-		mov eax,[bx-4]		; Type
+		add bx,16		; Advance to next
+		mov eax,[bx-8]		; Type
 		and eax,eax		; Null type?
 		jz .renew		; If so advance to next
 		mov [es:di+16],eax
-		mov eax,[bx-12]		; Start addr (low)
+		and cl,~3
+		cmp ecx,24
+		jb .no_extattr
+		mov eax,[bx-4]		; Extended attributes
+		mov [es:di+20],eax
+		mov ecx,24		; Bytes loaded
+.no_extattr:
+		push ecx
+		mov eax,[bx-16]		; Start addr (low)
 		mov [es:di],eax
-		mov ecx,[bx-8]		; Start addr (high)
-		mov [es:di+4],ecx
+		mov ecx,[bx-12]		; Start addr (high)
+		mov [es:di+4],edx
 		mov eax,[bx]		; End addr (low)
-		mov ecx,[bx+4]		; End addr (high)
-		sub eax,[bx-12]		; Derive the length
-		sbb ecx,[bx-8]
+		mov edx,[bx+4]		; End addr (high)
+		sub eax,[bx-16]		; Derive the length
+		sbb edx,[bx-12]
 		mov [es:di+8],eax	; Length (low)
 		mov [es:di+12],ecx	; Length (high)
 		cmp dword [bx+8],-1	; Type of next = end?
 		jne .notdone
 		xor ebx,ebx		; Done with table
 .notdone:
-		mov eax,edx		; "SMAP"
+		pop eax			; "SMAP"
 		pop ds
-		mov ecx,20		; Bytes loaded
 int15_success:
 		mov byte [bp+6], 02h	; Clear CF
 		pop bp
diff --git a/memdisk/msetup.c b/memdisk/msetup.c
index 12ba2179..f126d878 100644
--- a/memdisk/msetup.c
+++ b/memdisk/msetup.c
@@ -27,6 +27,7 @@ static inline int get_e820(void)
     uint64_t base;
     uint64_t len;
     uint32_t type;
+    uint32_t extattr;
   } *buf = sys_bounce;
   uint32_t copied;
   int range_count = 0;
@@ -47,12 +48,18 @@ static inline int get_e820(void)
     if ( regs.eax.l != 0x534d4150 || copied < 20 )
       break;
 
-    printf("e820: %08x%08x %08x%08x %d\n",
+    if ( copied < 24 )
+      buf->extattr = 1;
+
+    printf("e820: %08x%08x %08x%08x %d [%x]\n",
 	   (uint32_t)(buf->base >> 32), (uint32_t)buf->base,
 	   (uint32_t)(buf->len >> 32), (uint32_t)buf->len,
-	   buf->type);
+	   buf->type, buf->extattr);
+
+    if ( !(buf->extattr & 1) )
+      continue;			/* Disabled range, just ignore */
 
-    insertrange(buf->base, buf->len, buf->type);
+    insertrange(buf->base, buf->len, buf->type, buf->extattr);
     range_count++;
 
   } while ( regs.ebx.l );
@@ -66,7 +73,7 @@ static inline void get_dos_mem(void)
 
   memset(&regs, 0, sizeof regs);
   syscall(0x12, &regs, &regs);
-  insertrange(0, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1);
+  insertrange(0, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1, 1);
   printf(" DOS: %d K\n", regs.eax.w[0]);
 }
 
@@ -82,10 +89,10 @@ static inline int get_e801(void)
 
   if ( !(err = regs.eflags.l & 1) ) {
     if ( regs.eax.w[0] ) {
-      insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1);
+      insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1, 1);
     }
     if ( regs.ebx.w[0] ) {
-      insertrange(0x1000000, (uint64_t)((uint32_t)regs.ebx.w[0] << 16), 1);
+      insertrange(0x1000000, (uint64_t)((uint32_t)regs.ebx.w[0] << 16), 1, 1);
     }
 
     printf("e801: %04x %04x\n", regs.eax.w[0], regs.ebx.w[0]);
@@ -107,7 +114,7 @@ static inline int get_88(void)
 
   if ( !(err = regs.eflags.l & 1) ) {
     if ( regs.eax.w[0] ) {
-      insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1);
+      insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1, 1);
     }
 
     printf("  88: %04x\n", regs.eax.w[0]);
diff --git a/memdisk/setup.c b/memdisk/setup.c
index 583570ea..a52f136c 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -654,7 +654,7 @@ __cdecl void setup(__cdecl syscall_t cs_syscall, void *cs_bounce)
 	 do_edd ? "on" : "off");
 
   /* Reserve the ramdisk memory */
-  insertrange(ramdisk_image, ramdisk_size, 2);
+  insertrange(ramdisk_image, ramdisk_size, 2, 1);
   parse_mem();			/* Recompute variables */
 
   /* Figure out where it needs to go */
@@ -772,7 +772,7 @@ __cdecl void setup(__cdecl syscall_t cs_syscall, void *cs_bounce)
 
   /* Reserve this range of memory */
   wrz_16(BIOS_BASEMEM, driveraddr >> 10);
-  insertrange(driveraddr, dos_mem-driveraddr, 2);
+  insertrange(driveraddr, dos_mem-driveraddr, 2, 1);
   parse_mem();
 
   pptr->mem1mb     = low_mem  >> 10;