ROUNDUP to use '*' and '/' -- the compiler will optimize that for powers of
two anyway and this implementation works for other numbers as well.
* The thread::fault_handler use in C[++] code was broken with gcc 4. At least
when other functions were invoked. Trying to trick the compiler wasn't a
particularly good idea anyway, since the next compiler version could break
the trick again. So the general policy is to use the fault handlers only in
assembly code where we have full control. Changed that for x86 (save for the
vm86 mode, which has a similar mechanism), but not for the other
architectures.
* Introduced fault_handler, fault_handler_stack_pointer, and fault_jump_buffer
fields in the cpu_ent structure, which must be used instead of
thread::fault_handler in the kernel debugger. Consequently user_memcpy() must
not be used in the kernel debugger either. Introduced a debug_memcpy()
instead.
* Introduced debug_call_with_fault_handler() function which calls a function
in a setjmp() and fault handler context. The architecture specific backend
arch_debug_call_with_fault_handler() has only been implemented for x86 yet.
* Introduced debug_is_kernel_memory_accessible() for use in the kernel
debugger. It determines whether a range of memory can be accessed in the
way specified. The architecture specific back end
arch_vm_translation_map_is_kernel_page_accessible() has only been implemented
for x86 yet.
* Added arch_debug_unset_current_thread() (only implemented for x86) to unset
the current thread pointer in the kernel debugger. When entering the kernel
debugger we do some basic sanity checks of the currently set thread structure
and unset it, if they fail. This allows certain commands (most importantly
the stack trace command) to avoid accessing the thread structure.
* x86: When handling a double fault, we do now install a special handler for
page faults. This allows us to gracefully catch faulting commands, even if
e.g. the thread structure is toast.
We are now in much better shape to deal with double faults. Hopefully avoiding
the triple faults that some people have been experiencing on their hardware
and ideally even allowing to use the kernel debugger normally.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@32073 a95241bf-73f2-0310-859d-f6bbb57e9c96
ea2abd110b