arm64/HWCAP: Use system wide safe values

Extend struct arm64_cpu_capabilities to handle the HWCAP detection
and make use of the system wide value of the feature registers for
a reliable set of HWCAPs.

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index eec584e..ca46210 100644 (file)
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -81,6 +81,8 @@ struct arm64_cpu_capabilities {
                        u32 sys_reg;
                        int field_pos;
                        int min_field_value;
+                       int hwcap_type;
+                       unsigned long hwcap;
                };
        };
 };

diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index 0ad7351..400b80b 100644 (file)
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -52,6 +52,14 @@
 extern unsigned int compat_elf_hwcap, compat_elf_hwcap2;
 #endif
 
+enum {
+       CAP_HWCAP = 1,
+#ifdef CONFIG_COMPAT
+       CAP_COMPAT_HWCAP,
+       CAP_COMPAT_HWCAP2,
+#endif
+};
+
 extern unsigned long elf_hwcap;
 #endif
 #endif

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 8aff8fc..dd6997e 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -628,6 +628,89 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
        {},
 };
 
+#define HWCAP_CAP(reg, field, min_value, type, cap)            \
+       {                                                       \
+               .desc = #cap,                                   \
+               .matches = has_cpuid_feature,                   \
+               .sys_reg = reg,                                 \
+               .field_pos = field,                             \
+               .min_field_value = min_value,                   \
+               .hwcap_type = type,                             \
+               .hwcap = cap,                                   \
+       }
+
+static const struct arm64_cpu_capabilities arm64_hwcaps[] = {
+       HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, 2, CAP_HWCAP, HWCAP_PMULL),
+       HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_AES_SHIFT, 1, CAP_HWCAP, HWCAP_AES),
+       HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA1_SHIFT, 1, CAP_HWCAP, HWCAP_SHA1),
+       HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_SHA2_SHIFT, 1, CAP_HWCAP, HWCAP_SHA2),
+       HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_CRC32_SHIFT, 1, CAP_HWCAP, HWCAP_CRC32),
+       HWCAP_CAP(SYS_ID_AA64ISAR0_EL1, ID_AA64ISAR0_ATOMICS_SHIFT, 2, CAP_HWCAP, HWCAP_ATOMICS),
+#ifdef CONFIG_COMPAT
+       HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, 2, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_PMULL),
+       HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_AES_SHIFT, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_AES),
+       HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA1_SHIFT, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA1),
+       HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_SHA2_SHIFT, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_SHA2),
+       HWCAP_CAP(SYS_ID_ISAR5_EL1, ID_ISAR5_CRC32_SHIFT, 1, CAP_COMPAT_HWCAP2, COMPAT_HWCAP2_CRC32),
+#endif
+       {},
+};
+
+static void cap_set_hwcap(const struct arm64_cpu_capabilities *cap)
+{
+       switch (cap->hwcap_type) {
+       case CAP_HWCAP:
+               elf_hwcap |= cap->hwcap;
+               break;
+#ifdef CONFIG_COMPAT
+       case CAP_COMPAT_HWCAP:
+               compat_elf_hwcap |= (u32)cap->hwcap;
+               break;
+       case CAP_COMPAT_HWCAP2:
+               compat_elf_hwcap2 |= (u32)cap->hwcap;
+               break;
+#endif
+       default:
+               WARN_ON(1);
+               break;
+       }
+}
+
+/* Check if we have a particular HWCAP enabled */
+static bool cpus_have_hwcap(const struct arm64_cpu_capabilities *cap)
+{
+       bool rc;
+
+       switch (cap->hwcap_type) {
+       case CAP_HWCAP:
+               rc = (elf_hwcap & cap->hwcap) != 0;
+               break;
+#ifdef CONFIG_COMPAT
+       case CAP_COMPAT_HWCAP:
+               rc = (compat_elf_hwcap & (u32)cap->hwcap) != 0;
+               break;
+       case CAP_COMPAT_HWCAP2:
+               rc = (compat_elf_hwcap2 & (u32)cap->hwcap) != 0;
+               break;
+#endif
+       default:
+               WARN_ON(1);
+               rc = false;
+       }
+
+       return rc;
+}
+
+static void setup_cpu_hwcaps(void)
+{
+       int i;
+       const struct arm64_cpu_capabilities *hwcaps = arm64_hwcaps;
+
+       for (i = 0; hwcaps[i].desc; i++)
+               if (hwcaps[i].matches(&hwcaps[i]))
+                       cap_set_hwcap(&hwcaps[i]);
+}
+
 void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
                            const char *info)
 {
@@ -769,6 +852,13 @@ void verify_local_cpu_capabilities(void)
                if (caps[i].enable)
                        caps[i].enable(NULL);
        }
+
+       for (i = 0, caps = arm64_hwcaps; caps[i].desc; i++) {
+               if (!cpus_have_hwcap(&caps[i]))
+                       continue;
+               if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg), &caps[i]))
+                       fail_incapable_cpu("arm64_hwcaps", &caps[i]);
+       }
 }
 
 #else  /* !CONFIG_HOTPLUG_CPU */
@@ -787,13 +877,12 @@ static void setup_feature_capabilities(void)
 
 void __init setup_cpu_features(void)
 {
-       u64 features;
-       s64 block;
        u32 cwg;
        int cls;
 
        /* Set the CPU feature capabilies */
        setup_feature_capabilities();
+       setup_cpu_hwcaps();
 
        /* Advertise that we have computed the system capabilities */
        set_sys_caps_initialised();
@@ -809,74 +898,4 @@ void __init setup_cpu_features(void)
        if (L1_CACHE_BYTES < cls)
                pr_warn("L1_CACHE_BYTES smaller than the Cache Writeback Granule (%d < %d)\n",
                        L1_CACHE_BYTES, cls);
-
-       /*
-        * ID_AA64ISAR0_EL1 contains 4-bit wide signed feature blocks.
-        * The blocks we test below represent incremental functionality
-        * for non-negative values. Negative values are reserved.
-        */
-       features = read_cpuid(ID_AA64ISAR0_EL1);
-       block = cpuid_feature_extract_field(features, 4);
-       if (block > 0) {
-               switch (block) {
-               default:
-               case 2:
-                       elf_hwcap |= HWCAP_PMULL;
-               case 1:
-                       elf_hwcap |= HWCAP_AES;
-               case 0:
-                       break;
-               }
-       }
-
-       if (cpuid_feature_extract_field(features, 8) > 0)
-               elf_hwcap |= HWCAP_SHA1;
-
-       if (cpuid_feature_extract_field(features, 12) > 0)
-               elf_hwcap |= HWCAP_SHA2;
-
-       if (cpuid_feature_extract_field(features, 16) > 0)
-               elf_hwcap |= HWCAP_CRC32;
-
-       block = cpuid_feature_extract_field(features, 20);
-       if (block > 0) {
-               switch (block) {
-               default:
-               case 2:
-                       elf_hwcap |= HWCAP_ATOMICS;
-               case 1:
-                       /* RESERVED */
-               case 0:
-                       break;
-               }
-       }
-
-#ifdef CONFIG_COMPAT
-       /*
-        * ID_ISAR5_EL1 carries similar information as above, but pertaining to
-        * the AArch32 32-bit execution state.
-        */
-       features = read_cpuid(ID_ISAR5_EL1);
-       block = cpuid_feature_extract_field(features, 4);
-       if (block > 0) {
-               switch (block) {
-               default:
-               case 2:
-                       compat_elf_hwcap2 |= COMPAT_HWCAP2_PMULL;
-               case 1:
-                       compat_elf_hwcap2 |= COMPAT_HWCAP2_AES;
-               case 0:
-                       break;
-               }
-       }
-
-       if (cpuid_feature_extract_field(features, 8) > 0)
-               compat_elf_hwcap2 |= COMPAT_HWCAP2_SHA1;
-
-       if (cpuid_feature_extract_field(features, 12) > 0)
-               compat_elf_hwcap2 |= COMPAT_HWCAP2_SHA2;
-
-       if (cpuid_feature_extract_field(features, 16) > 0)
-               compat_elf_hwcap2 |= COMPAT_HWCAP2_CRC32;
-#endif
 }