Commit 78fd6dcf authored by Marc Zyngier's avatar Marc Zyngier Committed by Christoffer Dall

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: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarChristoffer Dall <cdall@linaro.org>
parent d68c1f7f
...@@ -108,9 +108,10 @@ __do_hyp_init: ...@@ -108,9 +108,10 @@ __do_hyp_init:
/* /*
* Preserve all the RES1 bits while setting the default flags, * 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) CPU_BE( orr x4, x4, #SCTLR_ELx_EE)
msr sctlr_el2, x4 msr sctlr_el2, x4
isb isb
......
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