[PATCH 0/1] MR571: ntdll: Fix floating point registers not being restored under Wow64.

[Brendan Shanks (＠bshanks)]

This bug showed up on macOS Wow64 where XMM registers weren't being restored after an exception.

[PATCH 1/1] ntdll: Fix floating point registers not being restored under Wow64.

[Brendan Shanks]

From: Brendan Shanks

---
 dlls/ntdll/unix/signal_x86_64.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index d6f19dbfa84..e2db56de76b 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -2026,10 +2026,12 @@ NTSTATUS set_thread_wow64_context( HANDLE handle, const void *ctx, ULONG size )
     if (flags & CONTEXT_I386_EXTENDED_REGISTERS)
     {
         memcpy( &frame->xsave, context->ExtendedRegisters, sizeof(frame->xsave) );
+        frame->restore_flags |= CONTEXT_FLOATING_POINT;
     }
     else if (flags & CONTEXT_I386_FLOATING_POINT)
     {
         fpu_to_fpux( &frame->xsave, &context->FloatSave );
+        frame->restore_flags |= CONTEXT_FLOATING_POINT;
     }
     if (flags & CONTEXT_I386_XSTATE)
     {

[PATCH 0/1] MR571: Draft: ntdll: Fix floating point registers not being restored under Wow64.

[Brendan Shanks (＠bshanks)]

Turns out this isn't complete, I'm getting infinite syscall fault loops which I think are caused by copy_context_64to32 not implementing FP+xstate copying yet.