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inside buffer, not outside

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This commit is contained in:
David Rose 2007-06-22 18:41:32 +00:00
parent d37e8b0dbf
commit e5aa103cd1
3 changed files with 8 additions and 17 deletions
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6
panda/src/pipeline/contextSwitch.c
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@ -257,7 +257,11 @@ setup_context_1(void) {
/* Now we overwrite the stack pointer value in the saved /* Now we overwrite the stack pointer value in the saved
register context. This doesn't work with all implementations register context. This doesn't work with all implementations
of setjmp/longjmp. */ of setjmp/longjmp. */
(*(void **)&temp[CS_JB_SP]) = (st_stack + st_stack_size);
/* We give ourselves a small buffer of unused space at the top
of the stack, to allow for the stack frame and such that this
code might be assuming is there. */
(*(void **)&temp[CS_JB_SP]) = (st_stack + st_stack_size - 0x100);
/* And finally, we place ourselves on the new stack by using /* And finally, we place ourselves on the new stack by using
longjmp() to reload the modified context. */ longjmp() to reload the modified context. */

18
panda/src/pipeline/threadSimpleImpl.cxx
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@ -79,7 +79,7 @@ ThreadSimpleImpl::
#ifdef WIN32 #ifdef WIN32
VirtualFree(_stack, 0, MEM_RELEASE); VirtualFree(_stack, 0, MEM_RELEASE);
#else #else
munmap(_stack, _stack_alloc_size); munmap(_stack, _stack_size);
#endif #endif
} }
} }
@ -115,25 +115,13 @@ start(ThreadPriority priority, bool joinable) {
nassertr(_stack == NULL, false); nassertr(_stack == NULL, false);
_stack_size = (size_t)thread_stack_size; _stack_size = (size_t)thread_stack_size;
// We allocate the requested stack size, plus an additional tiny
// buffer to allow room for the code to access values on the
// currently executing stack frame at the time we switch the stack.
_stack_alloc_size = _stack_size + 0x100;
#ifdef WIN32 #ifdef WIN32
// Windows case. // Windows case.
SYSTEM_INFO sysinfo; _stack = (unsigned char *)VirtualAlloc(NULL, _stack_size, MEM_COMMIT | MEM_RESERVE,
GetSystemInfo(&sysinfo);
size_t page_size = (size_t)sysinfo.dwPageSize;
_stack_alloc_size = ((_stack_alloc_size + page_size - 1) / page_size) * page_size;
_stack = (unsigned char *)VirtualAlloc(NULL, _stack_alloc_size, MEM_COMMIT | MEM_RESERVE,
PAGE_EXECUTE_READWRITE); PAGE_EXECUTE_READWRITE);
#else #else
// Posix case. // Posix case.
size_t page_size = getpagesize(); _stack = (unsigned char *)mmap(NULL, _stack_size, PROT_READ | PROT_WRITE | PROT_EXEC,
_stack_alloc_size = ((_stack_alloc_size + page_size - 1) / page_size) * page_size;
_stack = (unsigned char *)mmap(NULL, _stack_alloc_size, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANON, -1, 0); MAP_PRIVATE | MAP_ANON, -1, 0);
#endif #endif

1
panda/src/pipeline/threadSimpleImpl.h
View File

@ -115,7 +115,6 @@ private:
ThreadContext _context; ThreadContext _context;
unsigned char *_stack; unsigned char *_stack;
size_t _stack_size; size_t _stack_size;
size_t _stack_alloc_size;
#ifdef HAVE_PYTHON #ifdef HAVE_PYTHON
// If we might be working with Python, we have to manage the Python // If we might be working with Python, we have to manage the Python