Commit Graph

7 Commits

Author SHA1 Message Date
Warner Losh
86cb007f9f /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 22:18:23 +00:00
Marcel Moolenaar
6d33366c74 Update for the KDB framework:
o  ksym_start and ksym_end changed type to vm_offset_t.
o  Make debugging support conditional upon KDB instead of DDB.
o  Call kdb_enter() instead of breakpoint().
o  Remove implementation of Debugger().
o  Call kdb_trap() according to the new world order.

unwinder:
o  s/db_active/kdb_active/g
o  Various s/ddb/kdb/g
o  Add support for unwinding from the PCB as well as the trapframe.
   Abuse a spare field in the special register set to flag whether
   the PCB was actually constructed from a trapframe so that we can
   make the necessary adjustments.

md_var.h:
o   Add RSE convenience macros.
o   Add ia64_bsp_adjust() to add or subtract from BSP while taking
    NaT collections into account.
2004-07-10 22:59:30 +00:00
Marcel Moolenaar
480d3dd2ea Add logic to trace across/over a trapframe. We have ABI markers in
our unwind information for functions that are entry points into the
kernel. When stepping to the next frame, the unwinder will let us
know when sych a marker was encountered. We use this to stop the
current unwind session, query the trapframe and restart a new
unwind session based on the new trapframe.

The implementation is a bit sloppy, but at this time there are
bigger fish to fry.
2003-07-12 04:35:09 +00:00
Marcel Moolenaar
290245ea4c Don't call malloc() and free() while in the debugger and unwinding
to get a stacktrace. This does not work even with M_NOWAIT when we
have WITNESS and is generally a bad idea (pointed out by bde@). We
allocate an 8K heap for use by the unwinder when ddb is active. A
stack trace roughly takes up half of that in any case, so we have
some room for complex unwind situations. We don't want to waste too
much space though. Due to the nature of unwinding, we don't worry
too much about fragmentation or performance of unwinding while in
the debugger. For now we have our own heap management, but we may
be able to leverage from existing code at some later time.

While here:
o  Make sure we actually free the unwind environment after unwinding.
   This fixes a memory leak.
o  Replace Doug's license with mine in unwind.c and unwind.h. Both
   files don't have much, if any, of Doug's code left since the EPC
   syscall overhaul and the import of the unwinder.
o  Remove dead code.
o  Replace M_NOWAIT with M_WAITOK for all remaining malloc() calls.
2003-07-05 23:21:58 +00:00
Marcel Moolenaar
f2c49dd248 Revamp of the syscall path, exception and context handling. The
prime objectives are:
o  Implement a syscall path based on the epc inststruction (see
   sys/ia64/ia64/syscall.s).
o  Revisit the places were we need to save and restore registers
   and define those contexts in terms of the register sets (see
   sys/ia64/include/_regset.h).

Secundairy objectives:
o  Remove the requirement to use contigmalloc for kernel stacks.
o  Better handling of the high FP registers for SMP systems.
o  Switch to the new cpu_switch() and cpu_throw() semantics.
o  Add a good unwinder to reconstruct contexts for the rare
   cases we need to (see sys/contrib/ia64/libuwx)

Many files are affected by this change. Functionally it boils
down to:
o  The EPC syscall doesn't preserve registers it does not need
   to preserve and places the arguments differently on the stack.
   This affects libc and truss.
o  The address of the kernel page directory (kptdir) had to
   be unstaticized for use by the nested TLB fault handler.
   The name has been changed to ia64_kptdir to avoid conflicts.
   The renaming affects libkvm.
o  The trapframe only contains the special registers and the
   scratch registers. For syscalls using the EPC syscall path
   no scratch registers are saved. This affects all places where
   the trapframe is accessed. Most notably the unaligned access
   handler, the signal delivery code and the debugger.
o  Context switching only partly saves the special registers
   and the preserved registers. This affects cpu_switch() and
   triggered the move to the new semantics, which additionally
   affects cpu_throw().
o  The high FP registers are either in the PCB or on some
   CPU. context switching for them is done lazily. This affects
   trap().
o  The mcontext has room for all registers, but not all of them
   have to be defined in all cases. This mostly affects signal
   delivery code now. The *context syscalls are as of yet still
   unimplemented.

Many details went into the removal of the requirement to use
contigmalloc for kernel stacks. The details are mostly CPU
specific and limited to exception_save() and exception_restore().
The few places where we create, destroy or switch stacks were
mostly simplified by not having to construct physical addresses
and additionally saving the virtual addresses for later use.

Besides more efficient context saving and restoring, which of
course yields a noticable speedup, this also fixes the dreaded
SMP bootup problem as a side-effect. The details of which are
still not fully understood.

This change includes all the necessary backward compatibility
code to have it handle older userland binaries that use the
break instruction for syscalls. Support for break-based syscalls
has been pessimized in favor of a clean implementation. Due to
the overall better performance of the kernel, this will still
be notived as an improvement if it's noticed at all.

Approved by: re@ (jhb)
2003-05-16 21:26:42 +00:00
Marcel Moolenaar
c8a4afbc11 Update the unwind information when modules are loaded and unloaded
by using the linker hooks. Since these hooks are called for the
kernel as well, we don't need to deal with that with a special
SYSINIT. The initialization implicitly performed on the first
update of the unwind information is made explicit with a SYSINIT.
We now don't need the _ia64_unwind_{start|end} symbols.
2002-10-19 19:30:38 +00:00
Doug Rabson
d57b94ba65 * Factor out common code for manipulating the RSE backing store.
* Implement a fairly simplistic parser for unwinding stack frames.
* Use unwind records for DDB's 'trace' command. Also add support for
  tracing past exceptions to the context which generated the exception.

The stack unwind code requires a toolchain based on binutils-2.11.2 or
later and gcc-3.0.1 or later.
2001-10-29 12:04:23 +00:00