From 2ad0d05d3152c25aa97e5007f09534b3782298e6 Mon Sep 17 00:00:00 2001
From: Justine Tunney <jtunney@gmail.com>
Date: Sat, 16 Jan 2021 19:18:37 -0800
Subject: [PATCH] Avoid mapping above 4gb on Windows 7 x64 (#19)

Windows 7 support is now confirmed to be working. However it comes at
the cost of needing to workaround this tragically oppressive behavior
which is imposed for reasons unknown.

Fixes #19
---
 ape/ape.S                   |  2 +-
 libc/nt/memory.h            |  2 +-
 libc/runtime/memtrack.h     | 19 ++++++++++++++++---
 libc/runtime/winmain.greg.c |  8 +++++++-
 4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/ape/ape.S b/ape/ape.S
index 48095397..6dd6e08e 100644
--- a/ape/ape.S
+++ b/ape/ape.S
@@ -730,7 +730,7 @@ ape.macho:
 /	     ││││││││││┌5:HIGH_ENTROPY_VA
 /	     │││││││││││rrrrr
 .LDLLSTD = 0b0000000100100000
-.LDLLPIE = 0b0000000001000000
+.LDLLPIE = 0b0000000001100000
 .LDLLEXE = .LDLLSTD
 
 /	     ┌31:Writeable                        ┌─────────────────────────┐
diff --git a/libc/nt/memory.h b/libc/nt/memory.h
index b8dfe3e9..391ac328 100644
--- a/libc/nt/memory.h
+++ b/libc/nt/memory.h
@@ -29,7 +29,7 @@
 │ cosmopolitan § new technology » memory                                   ─╬─│┼
 ╚────────────────────────────────────────────────────────────────────────────│*/
 
-#define kNtNumaNoPreferredNode 0xffffffff
+#define kNtNumaNoPreferredNode 0xffffffffu
 
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
diff --git a/libc/runtime/memtrack.h b/libc/runtime/memtrack.h
index 40c734f8..0d1d8cce 100644
--- a/libc/runtime/memtrack.h
+++ b/libc/runtime/memtrack.h
@@ -1,13 +1,26 @@
 #ifndef COSMOPOLITAN_LIBC_RUNTIME_MEMTRACK_H_
 #define COSMOPOLITAN_LIBC_RUNTIME_MEMTRACK_H_
+#include "libc/dce.h"
 #include "libc/macros.h"
+#include "libc/nt/enum/version.h"
+#include "libc/nt/struct/teb.h"
 #include "libc/runtime/runtime.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
-#define kAutomapStart  0x0000100080000000  // asan can't spread its poison here
-#define kAutomapSize   0x00000fff80000000
-#define kFixedmapStart 0x0000200000000000
+#define _kAutomapStart  0x0000100080000000  // asan can't spread its poison here
+#define _kAutomapSize   0x00000fff80000000
+#define _kFixedmapStart 0x0000200000000000
+
+/*
+ * TODO: Why can't we allocate addresses above 4GB on Windows 7 x64?
+ * https://github.com/jart/cosmopolitan/issues/19
+ */
+#define MEMTRACK_ADDRESS(NORMAL, WIN7) \
+  (!(IsWindows() && NtGetVersion() < kNtVersionWindows10) ? NORMAL : WIN7)
+#define kAutomapStart  MEMTRACK_ADDRESS(_kAutomapStart, 0x10000000)
+#define kAutomapSize   MEMTRACK_ADDRESS(_kAutomapSize, 0x40000000)
+#define kFixedmapStart MEMTRACK_ADDRESS(_kFixedmapStart, 0x40000000)
 
 struct MemoryIntervals {
   int i;
diff --git a/libc/runtime/winmain.greg.c b/libc/runtime/winmain.greg.c
index 4554bd16..a7b16e07 100644
--- a/libc/runtime/winmain.greg.c
+++ b/libc/runtime/winmain.greg.c
@@ -43,6 +43,12 @@
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/prot.h"
 
+/*
+ * TODO: Why can't we allocate addresses above 4GB on Windows 7 x64?
+ * https://github.com/jart/cosmopolitan/issues/19
+ */
+#define ADDRESS 0x77700000 /*0000*/
+
 struct WinArgs {
   char *argv[512];
   char *envp[512];
@@ -128,7 +134,7 @@ static textwindows wontreturn void WinMainNew(void) {
   NormalizeCmdExe();
   *(/*unconst*/ int *)&__hostos = WINDOWS;
   size = ROUNDUP(STACKSIZE + sizeof(struct WinArgs), FRAMESIZE);
-  data = (intptr_t)AllocateMemory((char *)0x777000000000, size, &_mmi.p[0].h);
+  data = (intptr_t)AllocateMemory((char *)ADDRESS, size, &_mmi.p[0].h);
   _mmi.p[0].x = data >> 16;
   _mmi.p[0].y = (data >> 16) + ((size >> 16) - 1);
   _mmi.p[0].prot = PROT_READ | PROT_WRITE;