diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2017-06-06 19:08:34 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-14 15:05:56 +0200 |
| commit | 8abce1e49c82599e6c8ced2d3276247b06148526 (patch) | |
| tree | a8caa1c448d427594d8f54cbed59926d37d87549 /arch/arm64 | |
| parent | b9824dd75fcf6d9f10e8df08b237948d1802d5fe (diff) | |
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 4e460d973560..4bbff904169d 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -104,9 +104,10 @@ __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_ELx_FLAGS) + ldr x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) CPU_BE( orr x4, x4, #SCTLR_ELx_EE) msr sctlr_el2, x4 isb |