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authorMarc Zyngier <marc.zyngier@arm.com>2017-06-06 19:08:34 +0100
committerChristoffer Dall <cdall@linaro.org>2017-06-06 22:20:02 +0200
commit78fd6dcf11468a5a131b8365580d0c613bcc02cb (patch)
treeb762fe2d2b452eef518a8eb7c5db3e77b5a369d0
parentarm64: KVM: Preserve RES1 bits in SCTLR_EL2 (diff)
downloadlinux-dev-78fd6dcf11468a5a131b8365580d0c613bcc02cb.tar.xz
linux-dev-78fd6dcf11468a5a131b8365580d0c613bcc02cb.zip
arm64: KVM: Allow unaligned accesses at EL2
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. Cc: stable@vger.kernel.org Reported-by: Alexander Graf <agraf@suse.de> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@linaro.org>
Diffstat (limited to '')
-rw-r--r--arch/arm64/kvm/hyp-init.S5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 4072d408a4b4..3f9615582377 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -108,9 +108,10 @@ __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