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ntdll: Fix unwinding functions that end with a branch instruction. 

This happens with functions that aren't intended to return e.g. like
_Unwind_Resume. In these cases, the return address is outside of the
function (the first instruction in the next function).

Set the flag CONTEXT_UNWOUND_TO_CALL after unwinding to a callsite,
and if this flag is set, look up a RUNTIME_FUNCTION based on
Control.Pc - 4.

This isn't a complete (nor probably entirely correct) implementation
of the flag CONTEXT_UNWOUND_TO_CALL, but it practically seems to
work fine and fixes a large number of unwinding cases.

Signed-off-by: Martin Storsjo <martin@martin.st>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Martin Storsjo 2020-05-28 11:14:42 +03:00 committed by Alexandre Julliard
parent 42a5885669
commit babbf352b6
2 changed files with 14 additions and 1 deletions
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13
dlls/ntdll/signal_arm64.c
View File

@ -527,6 +527,7 @@ static NTSTATUS libunwind_virtual_unwind( ULONG_PTR ip, ULONG_PTR *frame, CONTEX
*frame = context->Sp;
context->Pc = context->u.s.Lr;
context->Sp = context->Sp + sizeof(ULONG64);
context->ContextFlags |= CONTEXT_UNWOUND_TO_CALL;
return STATUS_SUCCESS;
}
@ -577,6 +578,7 @@ static NTSTATUS libunwind_virtual_unwind( ULONG_PTR ip, ULONG_PTR *frame, CONTEX
unw_get_reg( &cursor, UNW_AARCH64_X30, (unw_word_t *)&context->u.s.Lr );
unw_get_reg( &cursor, UNW_AARCH64_SP, (unw_word_t *)&context->Sp );
context->Pc = context->u.s.Lr;
context->ContextFlags |= CONTEXT_UNWOUND_TO_CALL;
TRACE( "next function pc=%016lx%s\n", context->Pc, rc ? "" : " (last frame)" );
TRACE(" x0=%016lx x1=%016lx x2=%016lx x3=%016lx\n",
@ -614,10 +616,17 @@ static NTSTATUS virtual_unwind( ULONG type, DISPATCHER_CONTEXT *dispatch, CONTEX
dispatch->ScopeIndex = 0;
dispatch->EstablisherFrame = 0;
dispatch->ControlPc = context->Pc;
/*
* TODO: CONTEXT_UNWOUND_TO_CALL should be cleared if unwound past a
* signal frame.
*/
dispatch->ControlPcIsUnwound = (context->ContextFlags & CONTEXT_UNWOUND_TO_CALL) != 0;
/* first look for PE exception information */
if ((dispatch->FunctionEntry = lookup_function_info( context->Pc, &dispatch->ImageBase, &module )))
if ((dispatch->FunctionEntry = lookup_function_info(
context->Pc - (dispatch->ControlPcIsUnwound ? 4 : 0),
&dispatch->ImageBase, &module )))
{
dispatch->LanguageHandler = RtlVirtualUnwind( type, dispatch->ImageBase, context->Pc,
dispatch->FunctionEntry, context,
@ -654,6 +663,7 @@ static NTSTATUS virtual_unwind( ULONG type, DISPATCHER_CONTEXT *dispatch, CONTEX
dispatch->EstablisherFrame = context->u.s.Fp;
dispatch->LanguageHandler = NULL;
context->Pc = context->u.s.Lr;
context->ContextFlags |= CONTEXT_UNWOUND_TO_CALL;
return STATUS_SUCCESS;
}
@ -1758,6 +1768,7 @@ PVOID WINAPI RtlVirtualUnwind( ULONG type, ULONG_PTR base, ULONG_PTR pc,
TRACE( "ret: lr=%lx sp=%lx handler=%p\n", context->u.s.Lr, context->Sp, handler );
context->Pc = context->u.s.Lr;
context->ContextFlags |= CONTEXT_UNWOUND_TO_CALL;
*frame_ret = context->Sp;
return handler;
}

2
include/winnt.h
View File

@ -1863,6 +1863,8 @@ NTSYSAPI PVOID WINAPI RtlVirtualUnwind(DWORD,DWORD,DWORD,RUNTIME_FUNCTION*,CONTE
#define CONTEXT_FLOATING_POINT (CONTEXT_ARM64 | 0x00000004)
#define CONTEXT_DEBUG_REGISTERS (CONTEXT_ARM64 | 0x00000008)
#define CONTEXT_UNWOUND_TO_CALL 0x20000000
#define CONTEXT_FULL (CONTEXT_CONTROL | CONTEXT_INTEGER)
#define CONTEXT_ALL (CONTEXT_CONTROL | CONTEXT_INTEGER | CONTEXT_FLOATING_POINT | CONTEXT_DEBUG_REGISTERS)