Nicolas Pitre ec706dab29 ARM: add a vma entry for the user accessible vector page ... The kernel makes the high vector page visible to user space. This page contains (amongst others) small code segments that can be executed in user space. Make this page visible through ptrace and /proc/<pid>/mem in order to let gdb perform code parsing needed for proper unwinding. For example, the ERESTART_RESTARTBLOCK handler actually has a stack frame -- it returns to a PC value stored on the user's stack. To unwind after a "sleep" system call was interrupted twice, GDB would have to recognize this situation and understand that stack frame layout -- which it currently cannot do. We could fix this by hard-coding addresses in the vector page range into GDB, but that isn't really portable as not all of those addresses are guaranteed to remain stable across kernel releases. And having the gdb process make an exception for this page and get content from its own address space for it looks strange, and it is not future proof either. Being located above PAGE_OFFSET, this vma cannot be deleted by user space code. Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>		2010-10-01 22:35:19 -04:00
..
asm	ARM: add a vma entry for the user accessible vector page	2010-10-01 22:35:19 -04:00