perf-buildid-cache(1)
=====================

NAME
----
perf-buildid-cache - Manage build-id cache.

SYNOPSIS
--------
[verse]
'perf buildid-cache <options>'

DESCRIPTION
-----------
This command manages the build-id cache. It can add, remove, update and purge
files to/from the cache. In the future it should as well set upper limits for
the space used by the cache, etc.
This also scans the target binary for SDT (Statically Defined Tracing) and
record it along with the buildid-cache, which will be used by perf-probe.
For more details, see linkperf:perf-probe[1].

OPTIONS
-------
-a::
--add=::
        Add specified file to the cache.
-k::
--kcore::
        Add specified kcore file to the cache. For the current host that is
        /proc/kcore which requires root permissions to read. Be aware that
        running 'perf buildid-cache' as root may update root's build-id cache
        not the user's. Use the -v option to see where the file is created.
        Note that the copied file contains only code sections not the whole core
        image. Note also that files "kallsyms" and "modules" must also be in the
        same directory and are also copied.  All 3 files are created with read
        permissions for root only. kcore will not be added if there is already a
        kcore in the cache (with the same build-id) that has the same modules at
        the same addresses. Use the -v option to see if a copy of kcore is
        actually made.
-r::
--remove=::
        Remove a cached binary which has same build-id of specified file
        from the cache.
-p::
--purge=::
        Purge all cached binaries including older caches which have specified
	path from the cache.
-M::
--missing=::
	List missing build ids in the cache for the specified file.
-u::
--update=::
	Update specified file of the cache. Note that this doesn't remove
	older entires since those may be still needed for annotating old
	(or remote) perf.data. Only if there is already a cache which has
	exactly same build-id, that is replaced by new one. It can be used
	to update kallsyms and kernel dso to vmlinux in order to support
	annotation.

-v::
--verbose::
	Be more verbose.

SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-report[1], linkperf:perf-buildid-list[1]
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/sched?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>sched</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/sched/em_nbyte.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>em_nbyte.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='c8f325a59cfc718d13a50fbc746ed9b415c25e92'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;</td><td class='right'>2017-02-01 17:45:02 +0000</td></tr>
<tr><th>committer</th><td>Ingo Molnar &lt;mingo@kernel.org&gt;</td><td class='right'>2017-02-01 21:17:49 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/sched/em_nbyte.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/sched/em_nbyte.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>d53fbdac9d0781e39a13b2ac6b2bd258cf3b4140</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/sched/em_nbyte.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>net/sched/em_nbyte.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/sched/em_nbyte.c?id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/sched/em_nbyte.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92&amp;id2=bf29bddf0417a4783da3b24e8c9e017ac649326f'>diff</a>)</td></tr></table>
<div class='commit-subject'>efi/fdt: Avoid FDT manipulation after ExitBootServices()</div><div class='commit-msg'>Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.

Commit:

  abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")

fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().

Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.

So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)

Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.

Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Tested-by: Riku Voipio &lt;riku.voipio@linaro.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>Diffstat</a> (limited to 'net/sched/em_nbyte.c')</div><table summary='diffstat' class='diffstat'>