[PATCH 1/2] loader: On Mac, move the top-down allocations area down to avoid Rosetta regions.

[Brendan Shanks]

On Apple Silicon, Rosetta's shared cache starts at 0x7ffe00000000 and
the runtime is mapped below that.
Put the top-down allocation area below the runtime with plenty of room
to spare.

Signed-off-by: Brendan Shanks <bshanks(a)codeweavers.com>
---
 loader/preloader_mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/loader/preloader_mac.c b/loader/preloader_mac.c
index 43dc6b2b7e6..d86675538bb 100644
--- a/loader/preloader_mac.c
+++ b/loader/preloader_mac.c
@@ -79,7 +79,7 @@ static struct wine_preload_info preload_info[] =
     { (void *)0x000000010000, 0x00100000 },  /* DOS area */
     { (void *)0x000000110000, 0x67ef0000 },  /* low memory area */
     { (void *)0x00007ff00000, 0x000f0000 },  /* shared user data */
-    { (void *)0x7ffef0000000, 0x01ff0000 },  /* top-down allocations + virtual heap */
+    { (void *)0x7ffd00000000, 0x01ff0000 },  /* top-down allocations + virtual heap */
 #endif /* __i386__ */
     { 0, 0 },                            /* PE exe range set with WINEPRELOADRESERVE */
     { 0, 0 }                             /* end of list */
-- 
2.26.2

[PATCH 2/2] loader: On Mac, reserve an area starting at 4GB to force Rosetta's allocations higher.

[Brendan Shanks]

On Apple Silicon, Rosetta allocates memory starting at 0x100000000
(the 4GB line) before the preloader runs.
The .NET 3.5 installer and DirectX Jun2010 redistributable both contain
non-relocatable EXEs with that base address, which fail to run.

The workaround is to create an empty linker section at that address,
which is mapped by the kernel before Rosetta runs and forces Rosetta's
allocations higher in memory.
The linker section runs from 0x100000000-0x114000000.
Rosetta's allocations are ~132MB, and should end below 0x120000000.

This is not an exact science: a non-relocatable EXE with base address
between 0x114000000-0x120000000 will fail to run. If one is discovered,
the section size will need to be changed.

Signed-off-by: Brendan Shanks <bshanks(a)codeweavers.com>
---
 configure.ac           |  2 +-
 loader/preloader_mac.c | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 0f8b9f6c080..a9003523700 100644
--- a/configure.ac
+++ b/configure.ac
@@ -753,7 +753,7 @@ case $host_os in
     WINELOADER_LDFLAGS="-Wl,-pie,-pagezero_size,0x1000,-sectcreate,__TEXT,__info_plist,loader/wine_info.plist"
 
     wine_can_build_preloader=yes
-    WINEPRELOADER_LDFLAGS="-nostartfiles -nodefaultlibs -e _start -ldylib1.o -Wl,-image_base,0x7d400000,-pagezero_size,0x1000,-sectcreate,__TEXT,__info_plist,loader/wine_info.plist"
+    WINEPRELOADER_LDFLAGS="-nostartfiles -nodefaultlibs -e _start -ldylib1.o -Wl,-image_base,0x7d400000,-pagezero_size,0x1000,-sectcreate,__TEXT,__info_plist,loader/wine_info.plist,-segaddr,WINE_4GB_RESERVE,0x100000000"
     WINE_TRY_CFLAGS([-Wl,-no_new_main -e _main],
                     [WINEPRELOADER_LDFLAGS="-Wl,-no_new_main $WINEPRELOADER_LDFLAGS"
                      WINE_TRY_CFLAGS([-Wl,-no_new_main -e _main -nostartfiles -nodefaultlibs],,
diff --git a/loader/preloader_mac.c b/loader/preloader_mac.c
index d86675538bb..fc07b7da0ed 100644
--- a/loader/preloader_mac.c
+++ b/loader/preloader_mac.c
@@ -54,6 +54,17 @@
 #include "wine/asm.h"
 #include "main.h"
 
+/* Rosetta on Apple Silicon allocates memory starting at 0x100000000 (the 4GB line)
+ * before the preloader runs, which prevents any nonrelocatable EXEs with that
+ * base address from running.
+ *
+ * This empty linker section forces Rosetta's allocations (currently ~132 MB)
+ * to start at 0x114000000, and they should end below 0x120000000.
+ */
+#if defined(__x86_64__)
+__asm__(".zerofill WINE_4GB_RESERVE,WINE_4GB_RESERVE,___wine_4gb_reserve,0x14000000");
+#endif
+
 #ifndef LC_MAIN
 #define LC_MAIN 0x80000028
 struct entry_point_command
@@ -79,6 +90,7 @@ static struct wine_preload_info preload_info[] =
     { (void *)0x000000010000, 0x00100000 },  /* DOS area */
     { (void *)0x000000110000, 0x67ef0000 },  /* low memory area */
     { (void *)0x00007ff00000, 0x000f0000 },  /* shared user data */
+    { (void *)0x000100000000, 0x14000000 },  /* WINE_4GB_RESERVE section */
     { (void *)0x7ffd00000000, 0x01ff0000 },  /* top-down allocations + virtual heap */
 #endif /* __i386__ */
     { 0, 0 },                            /* PE exe range set with WINEPRELOADRESERVE */
@@ -395,6 +407,10 @@ static int preloader_overlaps_range( const void *start, const void *end )
             struct target_segment_command *seg = (struct target_segment_command*)cmd;
             const void *seg_start = (const void*)(seg->vmaddr + slide);
             const void *seg_end = (const char*)seg_start + seg->vmsize;
+            static const char reserved_segname[] = "WINE_4GB_RESERVE";
+
+            if (!wld_strncmp( seg->segname, reserved_segname, sizeof(reserved_segname)-1 ))
+                continue;
 
             if (end > seg_start && start <= seg_end)
             {
-- 
2.26.2