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From:   Mian Yousaf Kaukab <ykaukab@suse.de>
To:     will.deacon@arm.com, marc.zyngier@arm.com
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        robert.richter@cavium.com, cwu@amperecomputing.com,
        Mian Yousaf Kaukab <ykaukab@suse.de>
Subject: [PATCH RESEND 2/6] arm64: add sysfs vulnerability show for meltdown
Date:   Mon, 27 Aug 2018 16:33:06 +0200
Message-Id: <20180827143310.641-3-ykaukab@suse.de>
In-Reply-To: <20180827143310.641-1-ykaukab@suse.de>
References: <20180827143310.641-1-ykaukab@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Checking CSV3 support directly in case CONFIG_UNMAP_KERNEL_AT_EL0
is not enabled.

Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
---
 arch/arm64/kernel/cpu_errata.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index dec10898d688..996edb4e18ad 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -22,6 +22,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/cpufeature.h>
+#include <asm/mmu.h>
 
 static bool __maybe_unused
 is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)
@@ -683,3 +684,26 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 	{
 	}
 };
+
+#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
+
+ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	u64 pfr0;
+	u32 csv3;
+
+	if (arm64_kernel_unmapped_at_el0())
+		return sprintf(buf, "Mitigation: KPTI\n");
+
+	pfr0 = read_cpuid(ID_AA64PFR0_EL1);
+	csv3 = cpuid_feature_extract_unsigned_field(pfr0,
+			ID_AA64PFR0_CSV3_SHIFT);
+
+	if (csv3 || is_cpu_meltdown_safe())
+		return sprintf(buf, "Not affected\n");
+
+	return sprintf(buf, "Vulnerable\n");
+}
+
+#endif
-- 
2.11.0