+ unsigned int lowmem, ebda_addr;
+
+ /* To determine the position of the EBDA and the */
+ /* end of conventional memory, we need to look at */
+ /* the BIOS data area. In a paravirtual environment */
+ /* that area is absent. We'll just have to assume */
+ /* that the paravirt case can handle memory setup */
+ /* correctly, without our help. */
+#ifdef CONFIG_PARAVIRT
+ if ((boot_params.hdr.version >= 0x207) &&
+ (boot_params.hdr.hardware_subarch != 0)) {
+ return;
+ }
+#endif
+
+ /* end of low (conventional) memory */
+ lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
+ lowmem <<= 10;
+
+ /* start of EBDA area */
+ ebda_addr = *(unsigned short *)__va(BIOS_EBDA_SEGMENT);
+ ebda_addr <<= 4;
+
+ /* Fixup: bios puts an EBDA in the top 64K segment */
+ /* of conventional memory, but does not adjust lowmem. */
+ if ((lowmem - ebda_addr) <= 0x10000)
+ lowmem = ebda_addr;
+
+ /* Fixup: bios does not report an EBDA at all. */
+ /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
+ if ((ebda_addr == 0) && (lowmem >= 0x9f000))
+ lowmem = 0x9f000;
+
+ /* Paranoia: should never happen, but... */
+ if ((lowmem == 0) || (lowmem >= 0x100000))
+ lowmem = 0x9f000;
+
+ /* reserve all memory between lowmem and the 1MB mark */
+ reserve_bootmem(lowmem, 0x100000 - lowmem, BOOTMEM_DEFAULT);