Date: Fri, 18 Jun 1999 13:24:14 -0400 From: Richard Cownie <tich@ma.ikos.com> To: freebsd-current@freebsd.org, tich@par28.ma.ikos.com Subject: fix for 4GB dram Message-ID: <199906181724.NAA15730@par28.ma.ikos.com>
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I seem to have a fix for the 4GB dram problem.
Here's the SMAP info returned from the BIOS on an SC450NX with
4GB DRAM:
type=01 base= 00000000 00000000 len= 00000000 0009e400
type=02 base= 00000000 0009e400 len= 00000000 00001c00
type=02 base= 00000000 000f0400 len= 00000000 0000fc00
type=01 base= 00000000 00100000 len= 00000000 f9dfac00
type=03 base= 00000000 f9efac00 len= 00000000 00005000
type=04 base= 00000000 f9effc00 len= 00000000 00000400
type=02 base= 00000000 fe300000 len= 00000000 01d00000
type=01 base= 00000001 00000000 len= 00000000 06100000
Note that the chipset remaps some of the DRAM up above
the 4GB boundary - this entry in the table causes confusion,
because the base address gets truncated to 32bits (though
the comparison to detect non-monotonic entries is still
64bits).
I added this code in /usr/src/sys/i386/i386/machdep.c:getmemsize()
if (smap->type != 0x01)
goto next_run;
if (smap->length == 0)
goto next_run;
+ if (*(u_int32_t *)((char *)&smap->base + 4) != 0) {
+ if (boothowto & RB_VERBOSE) {
+ printf("Memory above 4GB ignored\n");
+ }
+ goto next_run;
+ }
for (i = 0; i <= physmap_idx; i += 2) {
if (smap->base < physmap[i + 1]) {
if (boothowto & RB_VERBOSE)
printf(
"Overlapping or non-monotonic memory region, ignoring second region\n");
goto next_run;
}
}
Now it seems to work (with options MAXMEM="((4096-64)*1024)" - haven't
tried it with speculative memory probing yet).
Thanks to Jonathan Lemon for steering me in the right direction.
Richard Cownie (tich@ma.ikos.com)
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