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| author | Marc Zyngier <marc.zyngier@arm.com> | 2017-06-06 19:08:34 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-09-15 18:30:04 +0100 |
| commit | 5e5c8768a5d2bce30d263e8844dfd2a69be33f41 (patch) | |
| tree | 9ab5347d1df97a17c3517d637eb40cadba2db47d /arch/arm64 | |
| parent | 79e1a7e336277c2e47b6844a8b7a9a38cc4f9e9b (diff) | |
| download | linux-stable-5e5c8768a5d2bce30d263e8844dfd2a69be33f41.tar.gz linux-stable-5e5c8768a5d2bce30d263e8844dfd2a69be33f41.tar.bz2 linux-stable-5e5c8768a5d2bce30d263e8844dfd2a69be33f41.zip | |
arm64: KVM: Allow unaligned accesses at EL2
commit 78fd6dcf11468a5a131b8365580d0c613bcc02cb upstream.
We currently have the SCTLR_EL2.A bit set, trapping unaligned accesses
at EL2, but we're not really prepared to deal with it. So far, this
has been unnoticed, until GCC 7 started emitting those (in particular
64bit writes on a 32bit boundary).
Since the rest of the kernel is pretty happy about that, let's follow
its example and set SCTLR_EL2.A to zero. Modern CPUs don't really
care.
Reported-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
[bwh: Backported to 3.16: s/ELx/EL2/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/kvm/hyp-init.S | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index a409482fc19b..29c47f7d6ecf 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -86,9 +86,10 @@ __do_hyp_init: /* * Preserve all the RES1 bits while setting the default flags, - * as well as the EE bit on BE. + * as well as the EE bit on BE. Drop the A flag since the compiler + * is allowed to generate unaligned accesses. */ - ldr x4, =(SCTLR_EL2_RES1 | SCTLR_EL2_FLAGS) + ldr x4, =(SCTLR_EL2_RES1 | (SCTLR_EL2_FLAGS & ~SCTLR_EL2_A)) CPU_BE( orr x4, x4, #SCTLR_EL2_EE) msr sctlr_el2, x4 isb |