evaluate_expression() so that any errors are caught and cause the function
to return to 0. Otherwise the errors posted an exception (via longjmp())
that aborted the current operation. This fixes the kld handling for
older kernels (6.x and 7.x) that don't have the full pathname stored in
the kernel linker.
MFC after: 3 days
a junk pointer and possibly causing a seg fault if we don't have any
non-kernel klds (or are unable to walk the list due to core / kernel
mismatch).
MFC after: 1 week
kgdb(8) now treats kld's as shared libraries relative to the kernel
"binary". Thus, you can use 'info sharedlibrary' to list the kld's
along with 'sharedlibrary' and 'nosharedlibrary' to manage symbol
loading and unloading. Note that there isn't an easy way to force GDB
to use a specific path for a shared library. However, you can use
'nosharedlibrary' to unload all the klds and then use 'sharedlibrary'
to load specific klds where it gets the kld correct and use
'add-kld' for the kld's where the default open behavior doesn't work.
klds opened via 'sharedlibrary' (and during startup) do have their
sections listed in 'info files'.
- Change the 'add-kld' command to use filename completion to complete its
argument.
and build a section table from the kernel file so that 'info files' output
for kgdb now matches the usage of gdb on a regular file with the exception
that we don't list sections for memory in the crash dump.
- Add a new 'kgdb_auto_load_klds()' routine which is invoked during
startup that walks the list of linker files and tries to find a matching
kld on disk for each non-kernel kld. If a kld file is found, then it
is added as if the 'add-kld' command is invoked. One change from
'add-kld' is that this method attempts to use the 'pathname' from the
linker_file structure first to try to load the file. If that fails
it then looks in the kernel directory followed by the directories in
the module path.
- Move the kld file suffix handling into a separate routine so that it
can be called standalone and to reduce duplicate code in find_kld_path().
- Cache the offsets of members of 'struct linker_file' during startup
instead of computing them for each 'add-kld'.
- Use GDB's target_read_string() instead of direct KVM access.
- Add all resident sections from a kld by using bfd_map_over_sections() to
build the section list rather than just adding symbols for ".text",
".data", ".bss", and ".rodata".
- Change the 'add-kld' command to do a y/n prompt before adding the
symbols when run interactively to match 'add-symbol-file'.
MFC after: 1 week
optional symbols that are missing (e.g. kgdb complains about _stoppcbs and
_stopped_cpus on UP kernels). Instead, callers that really want their
symbols to be present now do explicitly warnx() about the missing symbol.
crash dumps with kernel modules. The command is basically a wrapper
around add-symbol-file except that it uses the kernel linker data
structures and the ELF section headers of the kld to calculate the
section addresses add-symbol-file needs.
The 'kld' parameter may either be an absolute path or a relative path.
kgdb looks for the kld in several locations checking for variants with
".symbols" or ".debug" suffixes in each location. The first location it
tries is just opening the specified path (this handles absolute paths and
looks for the kld relative to the current directory otherwise). Next
it tries to find the module in the same directory of the kernel image
being used. If that fails it extracts the kern.module_path from the
kernel being debugged and looks in each of those paths.
The upshot is that for the common cases of debugging /boot/kernel/kernel
where the module is in either /boot/kernel or /boot/modules one can merely
do 'add-kld foo.ko'.
MFC after: 1 week
- Save td_oncpu in 'struct kthr' so the i386 target code can see which CPU
a thread is running on.
- Add a new frame unwinder for double fault frames. This unwinder is used
when "dblfault_handler" is encountered in the stack. It uses the CPU of
the current thread to lookup the base address of the TSS used for the
double fault from the GDT. It then fetches the various registers out
of the TSS similar to how the current trapframe unwinder fetches
registers out of the trapframe.
MFC after: 3 days
mode. This allows one to use kgdb on /dev/mem and be able to patch memory
on a live system. This is identical to what -wcore used to do in previous
gdb versions for FreeBSD.
Requested by: wpaul
list of frame sniffers so that trapframes can be detected. The kluge
is needed because this version of gdb only supports appending a
sniffer to the list of sniffers and the moment kgdb gets a chance to
add its own frame sniffer, the target's default frame sniffer is
already in the list. Since the default frame sniffer claims any
frame thrown at it, kgdb's frame sniffer never gets to smell (a
process much akin to tasting, but with lesser chance of hurling :-)
This commit adds dummy frame sniffers that never claim a frame and
as such don't fix anything yet. However, we now have frame sniffers
and they are being called, so it's just a matter of adding meat to
the bones and we'll be able to properly unwind across trapframes.
MFC after: 1 week
command does, but worse.
o Remove the obscure proc command, because it does what the thread
command does, but not unambigously.
o Move the PID to the extra thread info, where it makes sense and
where it doesn't confuse users. The extra thread info holds some
process information, to which the PID belongs.
o Implement the to_find_new_threads target method by having it call
the target beneath us if we're not using KVM. This makes sure that
new threads are found when using the remote target.
o Fix various core dump scenarios:
- Implement the to_files_info target method. Previously the
'info target' command would cause a NULL pointer dereference.
- Don't assume there's a current thread. We're not initialized
in all cases. This prevents a NULL pointer dereference.
- When we're not ussing KVM, have the to_xfer_memory target
method call the target beneath us. This avoids calling into
KVM with a NULL pointer.
MFC after: 1 week
static.
o Register a function with atexit(3) to close the KVM object if
we have one open.
o Show the unread portion of the kernel's message buffer before
presenting the prompt. It's bound to provide some useful info.
o Don't call kgdb_target() twice. It results in having all threads
listed twice.
MFC after: 1 week
in future calls, so we can't free it here. The right place to free the
buffer would be to be after kvm_close(), but we don't do that yet. A
static buffer would work too.
Reviewed by: marcel (who has other plans for this anyway)
Approved by: re
