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* miscfuncs.cc: Revert change from 2012-02-13 which used the 

Windows-provided stack rather than an own stack created in
	CygwinCreateThread.
	(struct thread_wrapper_arg): Rename commitsize to stacklimit.
	(CygwinCreateThread): Rename commitsize to real_stacklimit.
This commit is contained in:
Corinna Vinschen 2012-02-15 21:34:06 +00:00
parent 2d192e1ebb
commit fb97e87479
2 changed files with 164 additions and 127 deletions
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8
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,11 @@
2012-02-15 Corinna Vinschen <corinna@vinschen.de>
* miscfuncs.cc: Revert change from 2012-02-13 which used the
Windows-provided stack rather than an own stack created in
CygwinCreateThread.
(struct thread_wrapper_arg): Rename commitsize to stacklimit.
(CygwinCreateThread): Rename commitsize to real_stacklimit.
2012-02-15 Corinna Vinschen <corinna@vinschen.de>
* dtable.cc (dtable::init_std_file_from_handle): Use tmp_pathbuf for

283
winsup/cygwin/miscfuncs.cc
View File

@ -444,7 +444,7 @@ struct thread_wrapper_arg
PVOID arg;
PBYTE stackaddr;
PBYTE stackbase;
ULONG guardsize;
PBYTE stacklimit;
};
DWORD WINAPI
@ -458,127 +458,93 @@ thread_wrapper (VOID *arg)
thread_wrapper_arg wrapper_arg = *(thread_wrapper_arg *) arg;
cfree (arg);
/* Remove _cygtls from this stack since it won't be used anymore. */
_my_tls.remove (0);
/* Set stack values in TEB */
PTEB teb = NtCurrentTeb ();
teb->Tib.StackBase = wrapper_arg.stackbase;
teb->Tib.StackLimit = wrapper_arg.stacklimit ?: wrapper_arg.stackaddr;
/* Set DeallocationStack value. If we have an application-provided stack,
we set DeallocationStack to NULL, so NtTerminateThread does not deallocate
any stack. If we created the stack in CygwinCreateThread, we set
DeallocationStack to the stackaddr of our own stack, so it's automatically
deallocated when the thread is terminated. */
PBYTE dealloc_addr = (PBYTE) teb->DeallocationStack;
teb->DeallocationStack = wrapper_arg.stacklimit ? wrapper_arg.stackaddr
: NULL;
/* Store the OS-provided DeallocationStack address in wrapper_arg.stackaddr.
The below assembler code will release the OS stack after switching to our
new stack. */
wrapper_arg.stackaddr = dealloc_addr;
if (!wrapper_arg.stackaddr)
/* Initialize new _cygtls. */
_my_tls.init_thread (wrapper_arg.stackbase - CYGTLS_PADSIZE,
(DWORD (*)(void*, void*)) wrapper_arg.func);
/* Copy exception list over to new stack. I'm not quite sure how the
exception list is extended by Windows itself. What's clear is that it
always grows downwards and that it starts right at the stackbase.
Therefore we first count the number of exception records and place
the copy at the stackbase, too, so there's still a lot of room to
extend the list up to where our _cygtls region starts. */
_exception_list *old_start = (_exception_list *) teb->Tib.ExceptionList;
unsigned count = 0;
teb->Tib.ExceptionList = NULL;
for (_exception_list *e_ptr = old_start;
e_ptr && e_ptr != (_exception_list *) -1;
e_ptr = e_ptr->prev)
++count;
if (count)
{
/* The simple case: Windows-provided stack. */
/* If guardsize is exactly the page_size, we can assume that the
application will behave Windows conformant in terms of stack usage.
We can especially assume that it never allocates more than one
page at a time (alloca/_chkstk). Therefore, this is the default
case which allows a Windows compatible stack setup with a
reserved region, a guard page, and a commited region. We don't
need to set up a POSIX guardpage since Windows already handles
stack overflow: Trying to extend the stack into the last three
pages of the stack results in a SEGV. */
if (wrapper_arg.guardsize != wincap.page_size ())
_exception_list *new_start = (_exception_list *) wrapper_arg.stackbase
- count;
teb->Tib.ExceptionList = (struct _EXCEPTION_REGISTRATION_RECORD *)
new_start;
while (true)
{
/* However, if guardsize is set to something other than the
page size, we commit the entire stack, remove the Windows
guardpage and, if guardsize is > 0, set up a POSIX guardpage. */
DWORD old_prot;
ULONG stacksize = (uintptr_t) teb->Tib.StackBase
- (uintptr_t) teb->DeallocationStack;
VirtualAlloc (teb->DeallocationStack, stacksize,
MEM_COMMIT, PAGE_READWRITE);
VirtualProtect (teb->DeallocationStack, stacksize,
PAGE_READWRITE, &old_prot);
VirtualProtect (teb->DeallocationStack, wrapper_arg.guardsize,
PAGE_NOACCESS, &old_prot);
teb->Tib.StackLimit = (PVOID) ((PBYTE) teb->DeallocationStack
+ wrapper_arg.guardsize);
}
wrapper_arg.func (wrapper_arg.arg);
}
else
{
/* The tricky case: Application-provided stack. */
/* Remove _cygtls from this stack since it won't be used anymore. */
_my_tls.remove (0);
/* Set stack values in TEB */
teb->Tib.StackBase = wrapper_arg.stackbase;
teb->Tib.StackLimit = wrapper_arg.stackaddr;
/* Set DeallocationStack value. If we have an application-provided
stack, we set DeallocationStack to NULL, so NtTerminateThread does
not deallocate any stack. Store the OS-provided DeallocationStack
address in wrapper_arg.stackaddr. The below assembler code will
release the OS stack after switching to our new stack. */
wrapper_arg.stackaddr = (PBYTE) teb->DeallocationStack;
teb->DeallocationStack = NULL;
/* Initialize new _cygtls. */
_my_tls.init_thread (wrapper_arg.stackbase - CYGTLS_PADSIZE,
(DWORD (*)(void*, void*)) wrapper_arg.func);
/* Copy exception list over to new stack. I'm not quite sure how the
exception list is extended by Windows itself. What's clear is that it
always grows downwards and that it starts right at the stackbase.
Therefore we first count the number of exception records and place
the copy at the stackbase, too, so there's still a lot of room to
extend the list up to where our _cygtls region starts. */
_exception_list *old_start = (_exception_list *) teb->Tib.ExceptionList;
unsigned count = 0;
teb->Tib.ExceptionList = NULL;
for (_exception_list *e_ptr = old_start;
e_ptr && e_ptr != (_exception_list *) -1;
e_ptr = e_ptr->prev)
++count;
if (count)
{
_exception_list *new_start = (_exception_list *) wrapper_arg.stackbase
- count;
teb->Tib.ExceptionList = (struct _EXCEPTION_REGISTRATION_RECORD *)
new_start;
while (true)
new_start->handler = old_start->handler;
if (old_start->prev == (_exception_list *) -1)
{
new_start->handler = old_start->handler;
if (old_start->prev == (_exception_list *) -1)
{
new_start->prev = (_exception_list *) -1;
break;
}
new_start->prev = new_start + 1;
new_start = new_start->prev;
old_start = old_start->prev;
new_start->prev = (_exception_list *) -1;
break;
}
new_start->prev = new_start + 1;
new_start = new_start->prev;
old_start = old_start->prev;
}
__asm__ ("\n\
movl %[WRAPPER_ARG], %%ebx # Load &wrapper_arg into ebx \n\
movl (%%ebx), %%eax # Load thread func into eax \n\
movl 4(%%ebx), %%ecx # Load thread arg into ecx \n\
movl 8(%%ebx), %%edx # Load stackaddr into edx \n\
movl 12(%%ebx), %%ebx # Load stackbase into ebx \n\
subl %[CYGTLS], %%ebx # Subtract CYGTLS_PADSIZE \n\
subl $4, %%ebx # Subtract another 4 bytes \n\
movl %%ebx, %%esp # Set esp \n\
xorl %%ebp, %%ebp # Set ebp to 0 \n\
# Make gcc 3.x happy and align the stack so that it is \n\
# 16 byte aligned right before the final call opcode. \n\
andl $-16, %%esp # 16 byte align \n\
addl $-12, %%esp # 12 bytes + 4 byte arg = 16 \n\
# Now we moved to the new stack. Save thread func address\n\
# and thread arg on new stack \n\
pushl %%ecx # Push thread arg onto stack \n\
pushl %%eax # Push thread func onto stack \n\
# Now it's safe to release the OS stack. \n\
pushl $0x8000 # dwFreeType: MEM_RELEASE \n\
pushl $0x0 # dwSize: 0 \n\
pushl %%edx # lpAddress: stackaddr \n\
call _VirtualFree@12 # Shoot \n\
# All set. We can pop the thread function address from \n\
# the stack and call it. The thread arg is still on the \n\
# stack in the expected spot. \n\
popl %%eax # Pop thread_func address \n\
call *%%eax # Call thread func \n"
: : [WRAPPER_ARG] "r" (&wrapper_arg),
[CYGTLS] "i" (CYGTLS_PADSIZE));
}
__asm__ ("\n\
movl %[WRAPPER_ARG], %%ebx # Load &wrapper_arg into ebx \n\
movl (%%ebx), %%eax # Load thread func into eax \n\
movl 4(%%ebx), %%ecx # Load thread arg into ecx \n\
movl 8(%%ebx), %%edx # Load stackaddr into edx \n\
movl 12(%%ebx), %%ebx # Load stackbase into ebx \n\
subl %[CYGTLS], %%ebx # Subtract CYGTLS_PADSIZE \n\
subl $4, %%ebx # Subtract another 4 bytes \n\
movl %%ebx, %%esp # Set esp \n\
xorl %%ebp, %%ebp # Set ebp to 0 \n\
# Make gcc 3.x happy and align the stack so that it is \n\
# 16 byte aligned right before the final call opcode. \n\
andl $-16, %%esp # 16 byte align \n\
addl $-12, %%esp # 12 bytes + 4 byte arg = 16 \n\
# Now we moved to the new stack. Save thread func address\n\
# and thread arg on new stack \n\
pushl %%ecx # Push thread arg onto stack \n\
pushl %%eax # Push thread func onto stack \n\
# Now it's safe to release the OS stack. \n\
pushl $0x8000 # dwFreeType: MEM_RELEASE \n\
pushl $0x0 # dwSize: 0 \n\
pushl %%edx # lpAddress: stackaddr \n\
call _VirtualFree@12 # Shoot \n\
# All set. We can pop the thread function address from \n\
# the stack and call it. The thread arg is still on the \n\
# stack in the expected spot. \n\
popl %%eax # Pop thread_func address \n\
call *%%eax # Call thread func \n"
: : [WRAPPER_ARG] "r" (&wrapper_arg),
[CYGTLS] "i" (CYGTLS_PADSIZE));
/* Never return from here. */
ExitThread (0);
}
@ -588,9 +554,11 @@ CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func, PVOID thread_arg,
PVOID stackaddr, ULONG stacksize, ULONG guardsize,
DWORD creation_flags, LPDWORD thread_id)
{
PVOID real_stackaddr = NULL;
ULONG real_stacksize = 0;
ULONG real_guardsize = 0;
thread_wrapper_arg *wrapper_arg;
HANDLE thread = NULL;
wrapper_arg = (thread_wrapper_arg *) ccalloc (HEAP_STR, 1,
sizeof *wrapper_arg);
@ -610,7 +578,9 @@ CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func, PVOID thread_arg,
}
else
{
/* If not, we let CreateThread reserve the stack. */
PBYTE real_stacklimit;
/* If not, we have to create the stack here. */
real_stacksize = roundup2 (stacksize, wincap.page_size ());
real_guardsize = roundup2 (guardsize, wincap.page_size ());
/* Add the guardsize to the stacksize */
@ -622,17 +592,76 @@ CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func, PVOID thread_arg,
/* Now roundup the result to the next allocation boundary. */
real_stacksize = roundup2 (real_stacksize,
wincap.allocation_granularity ());
wrapper_arg->guardsize = real_guardsize;
/* Reserve stack.
FIXME? If the TOP_DOWN method tends to collide too much with
other stuff, we should provide our own mechanism to find a
suitable place for the stack. Top down from the start of
the Cygwin DLL comes to mind. */
real_stackaddr = VirtualAlloc (NULL, real_stacksize,
MEM_RESERVE | MEM_TOP_DOWN,
PAGE_READWRITE);
if (!real_stackaddr)
return NULL;
/* Set up committed region. Two cases: */
if (real_guardsize != wincap.page_size ())
{
/* If guardsize is set to something other than the page size, we
commit the entire stack and, if guardsize is > 0, we set up a
POSIX guardpage. We don't set up a Windows guardpage. */
if (!VirtualAlloc (real_stackaddr, real_guardsize, MEM_COMMIT,
PAGE_NOACCESS))
goto err;
real_stacklimit = (PBYTE) real_stackaddr + real_guardsize;
if (!VirtualAlloc (real_stacklimit, real_stacksize - real_guardsize,
MEM_COMMIT, PAGE_READWRITE))
goto err;
}
else
{
/* If guardsize is exactly the page_size, we can assume that the
application will behave Windows conformant in terms of stack usage.
We can especially assume that it never allocates more than one
page at a time (alloca/_chkstk). Therefore, this is the default
case which allows a Windows compatible stack setup with a
reserved region, a guard page, and a commited region. We don't
need to set up a POSIX guardpage since Windows already handles
stack overflow: Trying to extend the stack into the last three
pages of the stack results in a SEGV.
We always commit 64K here, starting with the guardpage. */
real_stacklimit = (PBYTE) real_stackaddr + real_stacksize
- wincap.allocation_granularity ();
if (!VirtualAlloc (real_stacklimit, wincap.page_size (), MEM_COMMIT,
PAGE_READWRITE | PAGE_GUARD))
goto err;
real_stacklimit += wincap.page_size ();
if (!VirtualAlloc (real_stacklimit, wincap.allocation_granularity ()
- wincap.page_size (), MEM_COMMIT,
PAGE_READWRITE))
goto err;
}
wrapper_arg->stackaddr = (PBYTE) real_stackaddr;
wrapper_arg->stackbase = (PBYTE) real_stackaddr + real_stacksize;
wrapper_arg->stacklimit = real_stacklimit;
}
/* Use the STACK_SIZE_PARAM_IS_A_RESERVATION parameter. This doesn't
work on Windows 2000, but either we deallocate the OS stack in
thread_wrapper anyway, or the reservation is rounded to the next Meg.
Nothing to worry about.
Note that we reserve a 256K stack as minimum size, not 64K, otherwise
the thread creation might crash the process due to a stack overflow. */
return CreateThread (&sec_none_nih, stackaddr ? 4 * PTHREAD_STACK_MIN
: real_stacksize,
thread_wrapper, wrapper_arg,
creation_flags | STACK_SIZE_PARAM_IS_A_RESERVATION,
thread_id);
/* Use the STACK_SIZE_PARAM_IS_A_RESERVATION parameter so only the
minimum size for a thread stack is reserved by the OS. This doesn't
work on Windows 2000, but we deallocate the OS stack in thread_wrapper
anyway, so this should be a problem only in a tight memory condition.
Note that we reserve a 256K stack, not 64K, otherwise the thread creation
might crash the process due to a stack overflow. */
thread = CreateThread (&sec_none_nih, 4 * PTHREAD_STACK_MIN,
thread_wrapper, wrapper_arg,
creation_flags | STACK_SIZE_PARAM_IS_A_RESERVATION,
thread_id);
err:
if (!thread && real_stackaddr)
{
/* Don't report the wrong error even though VirtualFree is very unlikely
to fail. */
DWORD err = GetLastError ();
VirtualFree (real_stackaddr, 0, MEM_RELEASE);
SetLastError (err);
}
return thread;
}