commit 42e2acde12 upstream.
Current powerpc security.c file is defining functions, as
cpu_show_meltdown(), cpu_show_spectre_v{1,2} and others, that are being
declared at linux/cpu.h header without including the header file that
contains these declarations.
This is being reported by sparse, which thinks that these functions are
static, due to the lack of declaration:
arch/powerpc/kernel/security.c:105:9: warning: symbol 'cpu_show_meltdown' was not declared. Should it be static?
arch/powerpc/kernel/security.c:139:9: warning: symbol 'cpu_show_spectre_v1' was not declared. Should it be static?
arch/powerpc/kernel/security.c:161:9: warning: symbol 'cpu_show_spectre_v2' was not declared. Should it be static?
arch/powerpc/kernel/security.c:209:6: warning: symbol 'stf_barrier' was not declared. Should it be static?
arch/powerpc/kernel/security.c:289:9: warning: symbol 'cpu_show_spec_store_bypass' was not declared. Should it be static?
This patch simply includes the proper header (linux/cpu.h) to match
function definition and declaration.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Major Hayden <major@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 92edf8df0f upstream.
When I updated the spectre_v2 reporting to handle software count cache
flush I got the logic wrong when there's no software count cache
enabled at all.
The result is that on systems with the software count cache flush
disabled we print:
Mitigation: Indirect branch cache disabled, Software count cache flush
Which correctly indicates that the count cache is disabled, but
incorrectly says the software count cache flush is enabled.
The root of the problem is that we are trying to handle all
combinations of options. But we know now that we only expect to see
the software count cache flush enabled if the other options are false.
So split the two cases, which simplifies the logic and fixes the bug.
We were also missing a space before "(hardware accelerated)".
The result is we see one of:
Mitigation: Indirect branch serialisation (kernel only)
Mitigation: Indirect branch cache disabled
Mitigation: Software count cache flush
Mitigation: Software count cache flush (hardware accelerated)
Fixes: ee13cb249f ("powerpc/64s: Add support for software count cache flush")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit f633a8ad63 upstream.
When the command line argument is present, the Spectre variant 2
mitigations are disabled.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 7d8bad99ba upstream.
Currently for CONFIG_PPC_FSL_BOOK3E the spectre_v2 file is incorrect:
$ cat /sys/devices/system/cpu/vulnerabilities/spectre_v2
"Mitigation: Software count cache flush"
Which is wrong. Fix it to report vulnerable for now.
Fixes: ee13cb249f ("powerpc/64s: Add support for software count cache flush")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ee13cb249f upstream.
Some CPU revisions support a mode where the count cache needs to be
flushed by software on context switch. Additionally some revisions may
have a hardware accelerated flush, in which case the software flush
sequence can be shortened.
If we detect the appropriate flag from firmware we patch a branch
into _switch() which takes us to a count cache flush sequence.
That sequence in turn may be patched to return early if we detect that
the CPU supports accelerating the flush sequence in hardware.
Add debugfs support for reporting the state of the flush, as well as
runtime disabling it.
And modify the spectre_v2 sysfs file to report the state of the
software flush.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 406d2b6ae3 upstream.
In a subsequent patch we will enable building security.c for Book3E.
However the NXP platforms are not vulnerable to Meltdown, so make the
Meltdown vulnerability reporting PPC_BOOK3S_64 specific.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6453b532f2 upstream.
NXP Book3E platforms are not vulnerable to speculative store
bypass, so make the mitigations PPC_BOOK3S_64 specific.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit cf175dc315 upstream.
The speculation barrier can be disabled from the command line
with the parameter: "nospectre_v1".
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6d44acae19 upstream.
When I added the spectre_v2 information in sysfs, I included the
availability of the ori31 speculation barrier.
Although the ori31 barrier can be used to mitigate v2, it's primarily
intended as a spectre v1 mitigation. Spectre v2 is mitigated by
hardware changes.
So rework the sysfs files to show the ori31 information in the
spectre_v1 file, rather than v2.
Currently we display eg:
$ grep . spectre_v*
spectre_v1:Mitigation: __user pointer sanitization
spectre_v2:Mitigation: Indirect branch cache disabled, ori31 speculation barrier enabled
After:
$ grep . spectre_v*
spectre_v1:Mitigation: __user pointer sanitization, ori31 speculation barrier enabled
spectre_v2:Mitigation: Indirect branch cache disabled
Fixes: d6fbe1c55c ("powerpc/64s: Wire up cpu_show_spectre_v2()")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit a377514519 upstream.
We now have barrier_nospec as mitigation so print it in
cpu_show_spectre_v1() when enabled.
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit cb3d6759a9 upstream.
Check what firmware told us and enable/disable the barrier_nospec as
appropriate.
We err on the side of enabling the barrier, as it's no-op on older
systems, see the comment for more detail.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 815069ca57 upstream.
Note that unlike RFI which is patched only in kernel the nospec state
reflects settings at the time the module was loaded.
Iterating all modules and re-patching every time the settings change
is not implemented.
Based on lwsync patching.
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 2eea7f067f upstream.
Based on the RFI patching. This is required to be able to disable the
speculation barrier.
Only one barrier type is supported and it does nothing when the
firmware does not enable it. Also re-patching modules is not supported
So the only meaningful thing that can be done is patching out the
speculation barrier at boot when the user says it is not wanted.
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit a048a07d7f upstream.
On some CPUs we can prevent a vulnerability related to store-to-load
forwarding by preventing store forwarding between privilege domains,
by inserting a barrier in kernel entry and exit paths.
This is known to be the case on at least Power7, Power8 and Power9
powerpc CPUs.
Barriers must be inserted generally before the first load after moving
to a higher privilege, and after the last store before moving to a
lower privilege, HV and PR privilege transitions must be protected.
Barriers are added as patch sections, with all kernel/hypervisor entry
points patched, and the exit points to lower privilge levels patched
similarly to the RFI flush patching.
Firmware advertisement is not implemented yet, so CPU flush types
are hard coded.
Thanks to Michal Suchánek for bug fixes and review.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michal Suchánek <msuchanek@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e7347a8683 upstream.
This moves the definition of the default security feature flags
(i.e., enabled by default) closer to the security feature flags.
This can be used to restore current flags to the default flags.
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d6fbe1c55c upstream.
Add a definition for cpu_show_spectre_v2() to override the generic
version. This has several permuations, though in practice some may not
occur we cater for any combination.
The most verbose is:
Mitigation: Indirect branch serialisation (kernel only), Indirect
branch cache disabled, ori31 speculation barrier enabled
We don't treat the ori31 speculation barrier as a mitigation on its
own, because it has to be *used* by code in order to be a mitigation
and we don't know if userspace is doing that. So if that's all we see
we say:
Vulnerable, ori31 speculation barrier enabled
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 56986016cb upstream.
Add a definition for cpu_show_spectre_v1() to override the generic
version. Currently this just prints "Not affected" or "Vulnerable"
based on the firmware flag.
Although the kernel does have array_index_nospec() in a few places, we
haven't yet audited all the powerpc code to see where it's necessary,
so for now we don't list that as a mitigation.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ff348355e9 upstream.
Now that we have the security feature flags we can make the
information displayed in the "meltdown" file more informative.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8ad3304156 upstream.
This landed in setup_64.c for no good reason other than we had nowhere
else to put it. Now that we have a security-related file, that is a
better place for it so move it.
[mpe: Add extern for rfi_flush to fix bisection break]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9a868f6343 upstream.
This commit adds security feature flags to reflect the settings we
receive from firmware regarding Spectre/Meltdown mitigations.
The feature names reflect the names we are given by firmware on bare
metal machines. See the hostboot source for details.
Arguably these could be firmware features, but that then requires them
to be read early in boot so they're available prior to asm feature
patching, but we don't actually want to use them for patching. We may
also want to dynamically update them in future, which would be
incompatible with the way firmware features work (at the moment at
least). So for now just make them separate flags.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
