Spectre-v1&v2 mitigation

GET — Wed, 09 Dec 2020 12:59:21 GMT

Hi,
Currently we use a 4.19.114 kernel in our builds.
During boot, I can see following log entry:
[ 0.000000] ARM_SMCCC_ARCH_WORKAROUND_1 missing from firmware

I can see this log entry comes from arch/arm64/kernel/cpu_errata.c, because detect_harden_bp_fw() returns -1 due to following defition in the drivers/firmware/psci.c:

struct psci_operations psci_ops = { .conduit = PSCI_CONDUIT_NONE, .smccc_version = SMCCC_VERSION_1_0, };

At the same time I can see that spectre-v2 mitigated and Spectre-v2 not:

# cat /sys/devices/system/cpu/vulnerabilities/* Not affected Not affected Not affected Not affected Vulnerable Mitigation: __user pointer sanitization Vulnerable Not affected # ls -l /sys/devices/system/cpu/vulnerabilities/* -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/itlb_multihit -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/l1tf -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/mds -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/meltdown -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/spec_store_bypass -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/spectre_v1 -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/spectre_v2 -r--r--r-- 1 root root 4096 Dec 8 12:18 /sys/devices/system/cpu/vulnerabilities/tsx_async_abort

We don't have any KVM options enabled in the defconfig.

I can see ARM trusted firmware has support for SMCCC 1.1

So my question is how to get rid of that log print and to properly apply possible mitigations? Can I just redefine psci_ops structure to use SMCCC version 1.1?

Re: Spectre-v1&v2 mitigation

yipingwang — Mon, 14 Dec 2020 06:33:05 GMT

Please refer to the following patch.

https://lore.kernel.org/linux-arm-kernel/20200506164411.3284-5-sudeep.holla@arm.com/#r

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Spectre-v1&v2 mitigation

Re: Spectre-v1&v2 mitigation