cache: Workaround HiSilicon Taishan DC CVAU

ascend inclusion
category: feature
bugzilla: 46922
CVE: NA

-------------------------------------

Taishan's L1/L2 cache is inclusive, and the data is consistent.
Any change of L1 does not require DC operation to brush CL in L1 to L2.
It's safe that don't clean data cache by address to point of unification.

Without IDC featrue, kernel needs to flush icache as well as dcache,
causes performance degradation.

The flaw refers to V110/V200 variant 1.
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: NDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NWeilong Chen <chenweilong@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

Documentation/arm64/silicon-errata.rst

@@ -143,6 +143,8 @@ stable kernels.
 +----------------+-----------------+-----------------+-----------------------------+
 | Hisilicon      | Hip08 SMMU PMCG | #162001800      | N/A                         |
 +----------------+-----------------+-----------------+-----------------------------+
+| Hisilicon      | TSV{110,200}    | #1980005        | HISILICON_ERRATUM_1980005   |
++----------------+-----------------+-----------------+-----------------------------+
 +----------------+-----------------+-----------------+-----------------------------+
 | Qualcomm Tech. | Kryo/Falkor v1  | E1003           | QCOM_FALKOR_ERRATUM_1003    |
 +----------------+-----------------+-----------------+-----------------------------+

arch/arm64/Kconfig

@@ -771,6 +771,15 @@ config HISILICON_ERRATUM_161600802
 
 	  If unsure, say Y.
 
+config HISILICON_ERRATUM_1980005
+	bool "Hisilicon erratum IDC support"
+	default n
+	help
+	  The HiSilicon TSV100/200 SoC support idc but report wrong value to
+	  kernel.
+
+	  If unsure, say N.
+
 config QCOM_FALKOR_ERRATUM_1003
 	bool "Falkor E1003: Incorrect translation due to ASID change"
 	default y

arch/arm64/include/asm/cpucaps.h

@@ -70,7 +70,8 @@
 #define ARM64_WORKAROUND_HISI_HIP08_RU_PREFETCH 60
 #define ARM64_CLEARPAGE_STNP			61
 #define ARM64_HAS_TWED				62
+#define ARM64_WORKAROUND_HISILICON_1980005	63
 
-#define ARM64_NCAPS				63
+#define ARM64_NCAPS				64
 
 #endif /* __ASM_CPUCAPS_H */

arch/arm64/kernel/cpu_errata.c

@@ -60,6 +60,29 @@ is_kryo_midr(const struct arm64_cpu_capabilities *entry, int scope)
 	return model == entry->midr_range.model;
 }
 
+#ifdef CONFIG_HISILICON_ERRATUM_1980005
+static bool
+hisilicon_1980005_match(const struct arm64_cpu_capabilities *entry,
+		int scope)
+{
+	static const struct midr_range idc_support_list[] = {
+		MIDR_ALL_VERSIONS(MIDR_HISI_TSV110),
+		MIDR_REV(MIDR_HISI_TSV200, 1, 0),
+		{ /* sentinel */ }
+	};
+
+	return  is_midr_in_range_list(read_cpuid_id(), idc_support_list);
+}
+
+static void
+hisilicon_1980005_enable(const struct arm64_cpu_capabilities *__unused)
+{
+	cpus_set_cap(ARM64_HAS_CACHE_IDC);
+	arm64_ftr_reg_ctrel0.sys_val |= BIT(CTR_IDC_SHIFT);
+	sysreg_clear_set(sctlr_el1, SCTLR_EL1_UCT, 0);
+}
+#endif
+
 static bool
 has_mismatched_cache_type(const struct arm64_cpu_capabilities *entry,
 			  int scope)
@@ -473,6 +496,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
 		.cpu_enable = cpu_enable_trap_ctr_access,
 	},
+#ifdef CONFIG_HISILICON_ERRATUM_1980005
+	{
+		.desc = "Taishan IDC coherence workaround",
+		.capability = ARM64_WORKAROUND_HISILICON_1980005,
+		.matches = hisilicon_1980005_match,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.cpu_enable = hisilicon_1980005_enable,
+	},
+#endif
 #ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
 	{
 		.desc = "Qualcomm Technologies Falkor/Kryo erratum 1003",