9boot: fix e820 scan

diff --git a/sys/src/boot/pc/e820.s b/sys/src/boot/pc/e820.s
index c830a64e68468db6d3aeac58b178bc451fa6071a..71db6c53d131d0a5aa5e2ed1a85412adfebbc985 100644 (file)
--- a/sys/src/boot/pc/e820.s
+++ b/sys/src/boot/pc/e820.s
@@ -4,17 +4,27 @@
 TEXT e820(SB), $0
        MOVL bx+4(SP), BX
        MOVL p+8(SP), DI
-
-       MOVL $0xe820, AX
+       MOVL $0xE820, AX
        MOVL $0x534D4150, DX
        CALL rmode16(SB)
        LWI(24, rCX)
        BIOSCALL(0x15)
        JC _bad
        CALL16(pmode32(SB))
+       CMPB CL, $24
+       JZ _ret
+       MOVL $1, AX
+       MOVL AX, 20(DI)
+_ret:
        MOVL BX, AX
        RET
 _bad:
        CALL16(pmode32(SB))
        XORL AX, AX
+       MOVL AX, 0(DI)
+       MOVL AX, 4(DI)
+       MOVL AX, 8(DI)
+       MOVL AX, 12(DI)
+       MOVL AX, 16(DI)
+       MOVL AX, 20(DI)
        RET

diff --git a/sys/src/boot/pc/sub.c b/sys/src/boot/pc/sub.c
index 8140508dc57a5260153ceca9ac90eb864fb7d962..fafe69ac02bf8fe4da736eb4b13be5dce1382977 100644 (file)
--- a/sys/src/boot/pc/sub.c
+++ b/sys/src/boot/pc/sub.c
@@ -340,27 +340,35 @@ e820conf(void)
        ulong bx;
        char *s;
 
-       memset(&e, 0, sizeof(e));
-       if((bx = e820(0, &e)) == 0)
-               return;
-
+       bx=0;
        s = confend;
-       memmove(confend, "e820=", 5);
-       confend += 5;
 
        do{
-               if(e.typ == 1 && (e.ext & 1) == 0 && e.len){
+               e.base = 0;
+               e.len = 0;
+               e.typ = 0;
+               e.ext = 1;
+               bx = e820(bx, &e);
+               if(e.typ == 1 && e.len != 0 && (e.ext & 3) == 1){
+                       if(confend == s){
+                               /* single entry <= 1MB is useless */
+                               if(bx == 0 && e.len <= 0x100000)
+                                       break;
+                               memmove(confend, "e820=", 5);
+                               confend += 5;
+                       }
                        v = e.base;
                        addconfx("", 8, v>>32);
                        addconfx("", 8, v&0xffffffff);
-                       v = e.base + e.len;
+                       v += e.len;
                        addconfx(" ", 8, v>>32);
                        addconfx("", 8, v&0xffffffff);
                        *confend++ = ' ';
                }
+       } while(bx);
 
-               memset(&e, 0, sizeof(e));
-       } while(bx = e820(bx, &e));
+       if(confend == s)
+               return;
 
        *confend = 0;
        print(s); print(crnl);