alpha-linux-user: Work around hosted mmap allocation problems
Signed-off-by: Richard Henderson <rth@twiddle.net>
diff --git a/target-alpha/cpu.h b/target-alpha/cpu.h
index 99f9ee1..5689760 100644
--- a/target-alpha/cpu.h
+++ b/target-alpha/cpu.h
@@ -40,9 +40,20 @@
#define TARGET_PAGE_BITS 13
+#ifdef CONFIG_USER_ONLY
+/* ??? The kernel likes to give addresses in high memory. If the host has
+ more virtual address space than the guest, this can lead to impossible
+ allocations. Honor the long-standing assumption that only kernel addrs
+ are negative, but otherwise allow allocations anywhere. This could lead
+ to tricky emulation problems for programs doing tagged addressing, but
+ that's far fewer than encounter the impossible allocation problem. */
+#define TARGET_PHYS_ADDR_SPACE_BITS 63
+#define TARGET_VIRT_ADDR_SPACE_BITS 63
+#else
/* ??? EV4 has 34 phys addr bits, EV5 has 40, EV6 has 44. */
-#define TARGET_PHYS_ADDR_SPACE_BITS 44
-#define TARGET_VIRT_ADDR_SPACE_BITS (30 + TARGET_PAGE_BITS)
+#define TARGET_PHYS_ADDR_SPACE_BITS 44
+#define TARGET_VIRT_ADDR_SPACE_BITS (30 + TARGET_PAGE_BITS)
+#endif
/* Alpha major type */
enum {
