o) Subtract 64K from the default userland stack pointer. GCC generate code

   that with a 32-bit ABI on a system with 64-bit registers can attempt to
   access an invalid (well, kernel) memory address rather than the intended
   user address for stack-relative loads and stores.  Lowering the stack
   pointer works around this. [1]
o) Make TRAP_DEBUG code conditional on the trap_debug variable.  Make
   trap_debug default to 0 instead of 1 now but make it possible to change it
   at runtime using sysctl.
o) Kill programs that attempt an unaligned access of a kernel address.  Note
   that with some ABIs, calling useracc() is not sufficient since the register
   may be 64-bit but vm_offset_t is 32-bit so a kernel address could be
   truncated to what looks like a valid user address, allowing the user to
   crash the kernel.
o) Clean up unaligned access emulation to support unaligned 16-bit and 64-bit
   accesses.  (For 16-bit accesses it was checking for user access to too much
   memory (4 bytes) and there was no 64-bit support.)  This still lacks support
   for unaligned load-linked and store-conditional.

Reviewed by:	[1] gonzo

0 files changed, 0 insertions, 0 deletions