wow64cpu: Use different JMP instruction to work around Rosetta bug.

Rosetta 2 on macOS 11 and 12 (before 12.4) does not support the 0xEA JMP instruction, use the indirect form instead. Signed-off-by: Brendan Shanks <bshanks@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

wow64cpu: Use different JMP instruction to work around Rosetta bug.
6d19495e · Brendan Shanks · Alexandre Julliard · 1a2482be · 6d19495e
Commit 6d19495e authored Apr 14, 2022 by Brendan Shanks Committed by Alexandre Julliard Apr 18, 2022
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cpu.c dlls/wow64cpu/cpu.c +6 -2

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--- a/dlls/wow64cpu/cpu.c
+++ b/dlls/wow64cpu/cpu.c
@@ -33,7 +33,9 @@ WINE_DEFAULT_DEBUG_CHANNEL(wow);
 #include "pshpack1.h"
 struct thunk_32to64
 {
-    BYTE  ljmp;   /* ljmp %cs:1f */
+    BYTE  ljmp;   /* jump far, absolute indirect */
+    BYTE  modrm;  /* address=disp32, opcode=5 */
+    DWORD op;
    DWORD addr;
    WORD  cs;
 };
@@ -195,7 +197,9 @@ NTSTATUS WINAPI BTCpuProcessInit(void)
    ds64_sel = context.SegDs;
    fs32_sel = context.SegFs;

-    thunk->ljmp = 0xea;
+    thunk->ljmp = 0xff;
+    thunk->modrm = 0x2d;
+    thunk->op   = PtrToUlong( &thunk->addr );
    thunk->addr = PtrToUlong( syscall_32to64 );
    thunk->cs   = cs64_sel;
    NtProtectVirtualMemory( GetCurrentProcess(), (void **)&thunk, &size, PAGE_EXECUTE_READ, &old_prot );