From 96d389ca10110d7eefb46feb6af9a0c6832f78f5 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Wed, 28 Oct 2020 13:28:39 -0500 Subject: arm64: Add workaround for Arm Cortex-A77 erratum 1508412 On Cortex-A77 r0p0 and r1p0, a sequence of a non-cacheable or device load and a store exclusive or PAR_EL1 read can cause a deadlock. The workaround requires a DMB SY before and after a PAR_EL1 register read. In addition, it's possible an interrupt (doing a device read) or KVM guest exit could be taken between the DMB and PAR read, so we also need a DMB before returning from interrupt and before returning to a guest. A deadlock is still possible with the workaround as KVM guests must also have the workaround. IOW, a malicious guest can deadlock an affected systems. This workaround also depends on a firmware counterpart to enable the h/w to insert DMB SY after load and store exclusive instructions. See the errata document SDEN-1152370 v10 [1] for more information. [1] https://static.docs.arm.com/101992/0010/Arm_Cortex_A77_MP074_Software_Developer_Errata_Notice_v10.pdf Signed-off-by: Rob Herring Reviewed-by: Catalin Marinas Acked-by: Marc Zyngier Cc: Catalin Marinas Cc: James Morse Cc: Suzuki K Poulose Cc: Will Deacon Cc: Julien Thierry Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20201028182839.166037-2-robh@kernel.org Signed-off-by: Will Deacon --- arch/arm64/include/asm/cpucaps.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/arm64/include/asm/cpucaps.h') diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 42868dbd29fd..e7d98997c09c 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -65,7 +65,8 @@ #define ARM64_HAS_ARMv8_4_TTL 55 #define ARM64_HAS_TLB_RANGE 56 #define ARM64_MTE 57 +#define ARM64_WORKAROUND_1508412 58 -#define ARM64_NCAPS 58 +#define ARM64_NCAPS 59 #endif /* __ASM_CPUCAPS_H */ -- cgit