From: Liav Rehana
User mode callee regs are explicitly collected before signal delivery
or breakpoint trap. r25 is special for kernel as it serves as task
pointer, so user mode value is clobbered very early. It is saved in
pt_regs where generally only scratch (caller saved) res are saved.
The
From: Liav Rehana
The instruction ld.as takes as operands a base address and an offset,
and doesn't access the sum of these two, but the sum of the base
address and a shifted version of the offset.
This isn't what we want in that case, since it causes a bug during
the push and pop of
