[PATCH v2 1/2] ntdll/tests: Add test for preserving x87 fpu state when capturing context.
Signed-off-by: Paul Gofman <gofmanp(a)gmail.com> --- v2: - simplify test. dlls/ntdll/tests/exception.c | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/dlls/ntdll/tests/exception.c b/dlls/ntdll/tests/exception.c index b8bd186632..f1a59f1dac 100644 --- a/dlls/ntdll/tests/exception.c +++ b/dlls/ntdll/tests/exception.c @@ -1509,9 +1509,12 @@ static void test_thread_context(void) struct expected { DWORD Eax, Ebx, Ecx, Edx, Esi, Edi, Ebp, Esp, Eip, - SegCs, SegDs, SegEs, SegFs, SegGs, SegSs, EFlags, prev_frame; + SegCs, SegDs, SegEs, SegFs, SegGs, SegSs, EFlags, prev_frame, + x87_control; } expect; - NTSTATUS (*func_ptr)( struct expected *res, void *func, void *arg1, void *arg2 ) = (void *)code_mem; + NTSTATUS (*func_ptr)( struct expected *res, void *func, void *arg1, void *arg2, + DWORD *new_x87_control ) = (void *)code_mem; + DWORD new_x87_control; static const BYTE call_func[] = { @@ -1542,10 +1545,20 @@ static void test_thread_context(void) 0x8f, 0x40, 0x3c, /* popl 0x3c(%eax) */ 0xff, 0x75, 0x00, /* pushl 0x0(%ebp) ; previous stack frame */ 0x8f, 0x40, 0x40, /* popl 0x40(%eax) */ + /* pushl $0x47f */ + 0x68, 0x7f, 0x04, 0x00, 0x00, + 0x8f, 0x40, 0x44, /* popl 0x44(%eax) */ + 0xd9, 0x68, 0x44, /* fldcw 0x44(%eax) */ + 0x8b, 0x00, /* mov (%eax),%eax */ 0xff, 0x75, 0x14, /* pushl 0x14(%ebp) */ 0xff, 0x75, 0x10, /* pushl 0x10(%ebp) */ 0xff, 0x55, 0x0c, /* call *0xc(%ebp) */ + + 0x8b, 0x55, 0x18, /* mov 0x18(%ebp),%edx */ + 0x9b, 0xd9, 0x3a, /* fstcw (%edx) */ + 0xdb, 0xe3, /* fninit */ + 0xc9, /* leave */ 0xc3, /* ret */ }; @@ -1557,7 +1570,7 @@ static void test_thread_context(void) memset( &context, 0xcc, sizeof(context) ); memset( &expect, 0xcc, sizeof(expect) ); - func_ptr( &expect, pRtlCaptureContext, &context, 0 ); + func_ptr( &expect, pRtlCaptureContext, &context, 0, &new_x87_control ); trace( "expect: eax=%08x ebx=%08x ecx=%08x edx=%08x esi=%08x edi=%08x ebp=%08x esp=%08x " "eip=%08x cs=%04x ds=%04x es=%04x fs=%04x gs=%04x ss=%04x flags=%08x prev=%08x\n", expect.Eax, expect.Ebx, expect.Ecx, expect.Edx, expect.Esi, expect.Edi, @@ -1593,8 +1606,9 @@ static void test_thread_context(void) memset( &context, 0xcc, sizeof(context) ); memset( &expect, 0xcc, sizeof(expect) ); - context.ContextFlags = CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS; - status = func_ptr( &expect, pNtGetContextThread, (void *)GetCurrentThread(), &context ); + context.ContextFlags = CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_SEGMENTS | CONTEXT_FLOATING_POINT; + + status = func_ptr( &expect, pNtGetContextThread, (void *)GetCurrentThread(), &context, &new_x87_control ); ok( status == STATUS_SUCCESS, "NtGetContextThread failed %08x\n", status ); trace( "expect: eax=%08x ebx=%08x ecx=%08x edx=%08x esi=%08x edi=%08x ebp=%08x esp=%08x " "eip=%08x cs=%04x ds=%04x es=%04x fs=%04x gs=%04x ss=%04x flags=%08x prev=%08x\n", @@ -1625,6 +1639,13 @@ static void test_thread_context(void) ok( context.SegFs == LOWORD(expect.SegFs), "wrong SegFs %08x/%08x\n", context.SegFs, expect.SegFs ); ok( context.SegGs == LOWORD(expect.SegGs), "wrong SegGs %08x/%08x\n", context.SegGs, expect.SegGs ); ok( context.SegSs == LOWORD(expect.SegSs), "wrong SegSs %08x/%08x\n", context.SegSs, expect.SegGs ); + + ok( LOWORD(context.FloatSave.ControlWord) == LOWORD(expect.x87_control), + "wrong x87 control word %#x/%#x.\n", context.FloatSave.ControlWord, expect.x87_control ); + todo_wine ok( LOWORD(expect.x87_control) == LOWORD(new_x87_control), + "x87 control word changed in NtGetContextThread() %#x/%#x.\n", + LOWORD(expect.x87_control), LOWORD(new_x87_control) ); + #undef COMPARE } -- 2.20.1
'FNSAVE' x87 instruction resets the FPU state to default values (like FINIT). This results in FPU state reset to default in any ntdll call which is getting x87 FPU state, e. g. obtaining context or raising an exception. Signed-off-by: Paul Gofman <gofmanp(a)gmail.com> --- v2: no changes. dlls/ntdll/signal_i386.c | 18 ++++++++++++++++++ dlls/ntdll/tests/exception.c | 2 +- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/dlls/ntdll/signal_i386.c b/dlls/ntdll/signal_i386.c index 0274a7d26d..f1deb1c65c 100644 --- a/dlls/ntdll/signal_i386.c +++ b/dlls/ntdll/signal_i386.c @@ -860,8 +860,26 @@ static inline void *init_handler( const ucontext_t *sigcontext, WORD *fs, WORD * static inline void save_fpu( CONTEXT *context ) { #ifdef __GNUC__ + struct + { + DWORD ControlWord; + DWORD StatusWord; + DWORD TagWord; + DWORD ErrorOffset; + DWORD ErrorSelector; + DWORD DataOffset; + DWORD DataSelector; + } + float_status; + context->ContextFlags |= CONTEXT_FLOATING_POINT; __asm__ __volatile__( "fnsave %0; fwait" : "=m" (context->FloatSave) ); + + /* Reset unmasked exceptions status to avoid firing an exception. */ + memcpy(&float_status, &context->FloatSave, sizeof(float_status)); + float_status.StatusWord &= float_status.ControlWord | 0xffffff80; + + __asm__ __volatile__( "fldenv %0" : "=m" (float_status) ); #endif } diff --git a/dlls/ntdll/tests/exception.c b/dlls/ntdll/tests/exception.c index f1a59f1dac..57ad30f180 100644 --- a/dlls/ntdll/tests/exception.c +++ b/dlls/ntdll/tests/exception.c @@ -1642,7 +1642,7 @@ static void test_thread_context(void) ok( LOWORD(context.FloatSave.ControlWord) == LOWORD(expect.x87_control), "wrong x87 control word %#x/%#x.\n", context.FloatSave.ControlWord, expect.x87_control ); - todo_wine ok( LOWORD(expect.x87_control) == LOWORD(new_x87_control), + ok( LOWORD(expect.x87_control) == LOWORD(new_x87_control), "x87 control word changed in NtGetContextThread() %#x/%#x.\n", LOWORD(expect.x87_control), LOWORD(new_x87_control) ); -- 2.20.1
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Paul Gofman