The object does not provide anonymous memory.
Reported by: kib
Reviewed by: kib
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22123
Summary:
PowerPC kernels are fully position independent, just like kernel modules.
The same fixups that are done for modules therefore need to be done to the
kernel, else symbol resolution in, e.g., DTrace, cannot resolve the kernel
symbols, so only addresses in the kernel are printed, while kernel module
symbols are printed.
Test Plan:
Run lockstat on powerpc64. Note symbols are resolved for kernel and
modules.
Reviewed By: markj
Differential Revision: https://reviews.freebsd.org/D20316
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
- Store the symbol table contents in an anonymous swap-backed object. Have
mmap(/dev/ksyms) map that object, and stop mapping the symbol table into
the calling process in ksyms_open(). Previously we would cache a pointer
to the pmap of the opening process, and mmap(/dev/ksyms) would create a
mapping using the physical address found by a pmap lookup at the initial
mapping address. However, this assumes that the cached pmap is valid,
which may not be the case. [1]
- Remove the ksyms ioctl interface. It appears to have been added to work
around a limitation in libelf that no longer exists; see r321842.
Moreover, the interface is difficult to support and isn't present in
illumos. Since ksyms was added specifically to support lockstat(1), it
is expected that this removal won't have any real impact.
- Simplify ksyms_read() to avoid unnecessary copying.
- Don't call the device handle destructor if we fail to capture a snapshot
of the kernel's symbol table. devfs will do that for us.
Reported by: Ilja van Sprundel <ivansprundel@ioactive.com> [1]
Reviewed by: kib (previous revision)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11789
The ksyms(4) device was added specifically for use by lockstat(1), which
as a DTrace consumer must run as root.
Discussed with: emaste
MFC after: 3 days
1) It is not useful to call "devfs_clear_cdevpriv()" from
"d_close" callbacks, hence for example read, write, ioctl and
so on might be sleeping at the time of "d_close" being called
and then then freed private data can still be accessed.
Examples: dtrace, linux_compat, ksyms (all fixed by this patch)
2) In sys/dev/drm* there are some cases in which memory will
be freed twice, if open fails, first by code in the open
routine, secondly by the cdevpriv destructor. Move registration
of the cdevpriv to the end of the drm open routines.
3) devfs_clear_cdevpriv() is not called if the "d_open" callback
registered cdevpriv data and the "d_open" callback function
returned an error. Fix this.
Discussed with: phk
MFC after: 2 weeks
It seems the D_PSEUDO flag was meant to allow make_dev() to return NULL.
Nowadays we have a different interface for that; make_dev_p(). There's
no need to keep it there.
While there, remove an unneeded D_NEEDMINOR from the gpio driver.
Discussed with: gonzo@ (gpio)
This replaces d_mmap() with the d_mmap2() implementation and also
changes the type of offset to vm_ooffset_t.
Purge d_mmap2().
All driver modules will need to be rebuilt since D_VERSION is also
bumped.
Reviewed by: jhb@
MFC after: Not in this lifetime...
Fix some wrong usages.
Note: this does not affect generated binaries as this argument is not used.
PR: 137213
Submitted by: Eygene Ryabinkin (initial version)
MFC after: 1 month
in symtab_get method symtab parameter is made constant as this reflects
actual intention and usage of the method
Reviewed by: imp, current@
Approved by: jhb (mentor)
get a quick snapshot of the kernel's symbol table including the symbols
from any loaded modules (the symbols are all merged into one symbol
table). Unlike like other implementations, this ksyms driver maps
memory in the process memory space to store the snapshot at the time
/dev/ksyms is opened. It also checks to see if the process has already
a snapshot open and won't allow it to open /dev/ksyms it again until it
closes first. This prevents kernel and process memory from being
exhausted. Note that /dev/ksyms is used by the lockstat(1) command.
Reviewed by: gallatin kib (freebsd-arch)
Approved by: gnn (mentor)
