[PATCH v2 0/2] MR2144: server: On macOS, fake debug registers when running under Rosetta.

[Brendan Shanks (＠bshanks)]

This was preventing wow64 from working on Apple Silicon/Rosetta.

Based on a patch by Tim Clem .

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54367

--
  v2: ntdll: Add a WARN when setting debug registers fails under Rosetta.
      server: On macOS, fake debug registers when running under Rosetta.

https://gitlab.winehq.org/wine/wine/-/merge_requests/2144

[PATCH v2 1/2] server: On macOS, fake debug registers when running under Rosetta.

[Brendan Shanks]

From: Brendan Shanks

Based on a patch by Tim Clem .

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54367
---
 server/mach.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/server/mach.c b/server/mach.c
index 6051396a1bf..3852bb3ee5b 100644
--- a/server/mach.c
+++ b/server/mach.c
@@ -31,6 +31,9 @@
 #ifdef HAVE_SYS_SYSCALL_H
 #include <sys/syscall.h>
 #endif
+#ifdef HAVE_SYS_SYSCTL_H
+#include <sys/sysctl.h>
+#endif

#include "ntstatus.h"
 #define WIN32_NO_STATUS
@@ -74,6 +77,25 @@ static mach_port_t get_process_port( struct process *process )
     return process->trace_data;
 }

+static int is_rosetta( void )
+{
+    static int rosetta_status, did_check = 0;
+    if (!did_check)
+    {
+        /* returns 0 for native process or on error, 1 for translated */
+        int ret = 0;
+        size_t size = sizeof(ret);
+        if (sysctlbyname( "sysctl.proc_translated", &ret, &size, NULL, 0 ) == -1)
+            rosetta_status = 0;
+        else
+            rosetta_status = ret;
+
+        did_check = 1;
+    }
+
+    return rosetta_status;
+}
+
 /* initialize the process control mechanism */
 void init_tracing_mechanism(void)
 {
@@ -165,6 +187,14 @@ void get_thread_context( struct thread *thread, context_t *context, unsigned int
     /* all other regs are handled on the client side */
     assert( flags == SERVER_CTX_DEBUG_REGISTERS );

+    if (is_rosetta())
+    {
+        /* getting debug registers of a translated process is not supported cross-process, return all zeroes */
+        memset( &context->debug, 0, sizeof(context->debug) );
+        context->flags |= SERVER_CTX_DEBUG_REGISTERS;
+        return;
+    }
+
     if (thread->unix_pid == -1 || !process_port ||
         mach_port_extract_right( process_port, thread->unix_tid,
                                  MACH_MSG_TYPE_COPY_SEND, &port, &type ))
@@ -251,6 +281,15 @@ void set_thread_context( struct thread *thread, const context_t *context, unsign
         return;
     }

+    if (is_rosetta())
+    {
+        /* Setting debug registers of a translated process is not supported cross-process
+         * (and even in-process, setting debug registers never has the desired effect).
+         */
+        set_error( STATUS_UNSUCCESSFUL );
+        return;
+    }
+
     /* get the debug state to determine which flavor to use */
     ret = thread_get_state(port, x86_DEBUG_STATE, (thread_state_t)&state, &count);
     if (ret)

[PATCH v2 2/2] ntdll: Add a WARN when setting debug registers fails under Rosetta.

[Brendan Shanks]

From: Brendan Shanks

---
 dlls/ntdll/unix/signal_x86_64.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 13fe7051c66..80d39406ada 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -1001,6 +1001,10 @@ NTSTATUS WINAPI NtSetContextThread( HANDLE handle, const CONTEXT *context )
     if (!self)
     {
         ret = set_thread_context( handle, context, &self, IMAGE_FILE_MACHINE_AMD64 );
+#ifdef __APPLE__
+        if ((flags & CONTEXT_DEBUG_REGISTERS) && (ret == STATUS_UNSUCCESSFUL))
+            WARN_(seh)( "Setting debug registers is not supported under Rosetta\n" );
+#endif
         if (ret || !self) return ret;
         if (flags & CONTEXT_DEBUG_REGISTERS)
         {