Based on a patch by Dávid Török.
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47970 Signed-off-by: Zebediah Figura z.figura12@gmail.com --- v2: Massage the context after returning to user mode; we may need it untouched for exceptions in 32-bit code.
Actually, the behaviour of segment registers on x86_64 Windows is more complicated:
* By default, %ss == %ds == %es == %gs == 0x2b; %cs == 0x33; %fs == 0x53.
* NtGetContextThread() does not capture the actual values, but instead returns the default values.
* All system calls restore all segments to their default values, including NtContinue().
* RtlRestoreContext() also restores all segments to their default values.
* SegDs, SegEs, SegFs, SegGs all restore default values in exception handlers; SegSs returns the actual value of %ss.
* RtlCaptureContext() does capture the actual values.
I did not test:
* whether %cs is correctly captured or restored in any functions;
* whether segment registers are restored from exception handlers (either to the default values or to the values set in the context).
We could, to a point, emulate the above, but it gets tricky. According to the Intel 64 and IA-32 Architectures Software Developer's Manual:
* %es, %ds, %ss can point to any segment—the entire contents of the descriptor table are effectively ignored (if I'm reading Volume 3 §3.4.4 right). However, they have to point to a *valid* segment (cf. Volume 1 §3.4.2.1).
* %cs is more restricted—the attributes in the descriptor table are also validated (Volume 3 §5.2.1).
* I don't even know about %fs and %gs; the manual is too vague and confusing.
dlls/ntdll/signal_x86_64.c | 4 ++++ dlls/ntdll/tests/exception.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c index b5be4f35758..d88f7ae553a 100644 --- a/dlls/ntdll/signal_x86_64.c +++ b/dlls/ntdll/signal_x86_64.c @@ -567,6 +567,10 @@ NTSTATUS WINAPI dispatch_exception( EXCEPTION_RECORD *rec, CONTEXT *context ) context->R12, context->R13, context->R14, context->R15 ); }
+ /* Legends of Runeterra depends on having SegDs == SegSs in an exception + * handler. */ + context->SegDs = context->SegSs; + if (call_vectored_handlers( rec, context ) == EXCEPTION_CONTINUE_EXECUTION) NtContinue( context, FALSE );
diff --git a/dlls/ntdll/tests/exception.c b/dlls/ntdll/tests/exception.c index 7c75606dd32..cdf3cdf8201 100644 --- a/dlls/ntdll/tests/exception.c +++ b/dlls/ntdll/tests/exception.c @@ -3020,7 +3020,7 @@ static DWORD WINAPI handler( EXCEPTION_RECORD *rec, ULONG64 frame, "%u: Unexpected exception address %p/%p\n", entry, rec->ExceptionAddress, (char*)context->Rip );
- todo_wine ok( context->SegDs == context->SegSs, + ok( context->SegDs == context->SegSs, "%u: ds %#x does not match ss %#x\n", entry, context->SegDs, context->SegSs ); todo_wine ok( context->SegEs == context->SegSs, "%u: es %#x does not match ss %#x\n", entry, context->SegEs, context->SegSs );