linux-stable.git/arch/powerpc, branch v4.4.185

KVM: PPC: Book3S: Use new mutex to synchronize access to rtas token list

2019-06-22T06:18:26+00:00

[ Upstream commit 1659e27d2bc1ef47b6d031abe01b467f18cb72d9 ]

Currently the Book 3S KVM code uses kvm->lock to synchronize access
to the kvm->arch.rtas_tokens list.  Because this list is scanned
inside kvmppc_rtas_hcall(), which is called with the vcpu mutex held,
taking kvm->lock cause a lock inversion problem, which could lead to
a deadlock.

To fix this, we add a new mutex, kvm->arch.rtas_token_lock, which nests
inside the vcpu mutexes, and use that instead of kvm->lock when
accessing the rtas token list.

This removes the lockdep_assert_held() in kvmppc_rtas_tokens_free().
At this point we don't hold the new mutex, but that is OK because
kvmppc_rtas_tokens_free() is only called when the whole VM is being
destroyed, and at that point nothing can be looking up a token in
the list.

Signed-off-by: Paul Mackerras 
Signed-off-by: Sasha Levin

powerpc/numa: improve control of topology updates

2019-06-11T10:23:58+00:00

[ Upstream commit 2d4d9b308f8f8dec68f6dbbff18c68ec7c6bd26f ]

When booted with "topology_updates=no", or when "off" is written to
/proc/powerpc/topology_updates, NUMA reassignments are inhibited for
PRRN and VPHN events. However, migration and suspend unconditionally
re-enable reassignments via start_topology_update(). This is
incoherent.

Check the topology_updates_enabled flag in
start/stop_topology_update() so that callers of those APIs need not be
aware of whether reassignments are enabled. This allows the
administrative decision on reassignments to remain in force across
migrations and suspensions.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin

powerpc/boot: Fix missing check of lseek() return value

2019-06-11T10:23:54+00:00

[ Upstream commit 5d085ec04a000fefb5182d3b03ee46ca96d8389b ]

This is detected by Coverity scan: CID: 1440481

Signed-off-by: Bo YU 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin

powerpc/lib: fix book3s/32 boot failure due to code patching

2019-05-16T17:45:18+00:00

commit b45ba4a51cde29b2939365ef0c07ad34c8321789 upstream.

Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).

As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().

This modification also has the advantage of avoiding unnecessary
remappings.

Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/booke64: set RI in default MSR

2019-05-16T17:45:18+00:00

commit 5266e58d6cd90ac85c187d673093ad9cb649e16d upstream.

Set RI in the default kernel's MSR so that the architected way of
detecting unrecoverable machine check interrupts has a chance to work.
This is inline with the MSR setup of the rest of booke powerpc
architectures configured here.

Signed-off-by: Laurentiu Tudor 
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Include cpu header

2019-05-16T17:45:16+00:00

commit 42e2acde1237878462b028f5a27d9cc5bea7502c 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 
Signed-off-by: Michael Ellerman 
Cc: Joel Stanley 
Cc: Nathan Chancellor 
Cc: Major Hayden 
Signed-off-by: Greg Kroah-Hartman

powerpc/fsl: Fixed warning: orphan section `__btb_flush_fixup'

2019-05-16T17:44:55+00:00

commit 039daac5526932ec731e4499613018d263af8b3e upstream.

Fixed the following build warning:
powerpc-linux-gnu-ld: warning: orphan section `__btb_flush_fixup' from
`arch/powerpc/kernel/head_44x.o' being placed in section
`__btb_flush_fixup'.

Signed-off-by: Diana Craciun 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/fsl: Sanitize the syscall table for NXP PowerPC 32 bit platforms

2019-05-16T17:44:55+00:00

commit c28218d4abbf4f2035495334d8bfcba64bda4787 upstream.

Used barrier_nospec to sanitize the syscall table.

Signed-off-by: Diana Craciun 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/fsl: Flush the branch predictor at each kernel entry (32 bit)

2019-05-16T17:44:53+00:00

commit 7fef436295bf6c05effe682c8797dfcb0deb112a upstream.

In order to protect against speculation attacks on
indirect branches, the branch predictor is flushed at
kernel entry to protect for the following situations:
- userspace process attacking another userspace process
- userspace process attacking the kernel
Basically when the privillege level change (i.e.the kernel
is entered), the branch predictor state is flushed.

Signed-off-by: Diana Craciun 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/fsl: Emulate SPRN_BUCSR register

2019-05-16T17:44:53+00:00

commit 98518c4d8728656db349f875fcbbc7c126d4c973 upstream.

In order to flush the branch predictor the guest kernel performs
writes to the BUCSR register which is hypervisor privilleged. However,
the branch predictor is flushed at each KVM entry, so the branch
predictor has been already flushed, so just return as soon as possible
to guest.

Signed-off-by: Diana Craciun 
[mpe: Tweak comment formatting]
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman