On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1),
memory accesses may cause undefined fault (Data abort,
DFSC=0b111111) due to the CPU Errata (Fujitsu #010001).

This patch introduces the workaround to the problem.
The workaround is to change the fault handler for Data abort
DFSC=0b111111 to ignore this undefined fault, which will only
affect the Fujitsu-A64FX.

Signed-off-by: Lei Zhang <zhang....@jp.fujitsu.com>
Tested-by: Lei Zhang <zhang....@jp.fujitsu.com>
---
 Documentation/arm64/silicon-errata.txt |  1 +
 arch/arm64/Kconfig                     | 13 +++++++++++++
 arch/arm64/include/asm/cpucaps.h       |  3 ++-
 arch/arm64/include/asm/cputype.h       |  4 ++++
 arch/arm64/kernel/cpu_errata.c         |  8 ++++++++
 arch/arm64/mm/fault.c                  | 24 +++++++++++++++++++++++-
 6 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/Documentation/arm64/silicon-errata.txt 
b/Documentation/arm64/silicon-errata.txt
index 1f09d04..26d64e9 100644
--- a/Documentation/arm64/silicon-errata.txt
+++ b/Documentation/arm64/silicon-errata.txt
@@ -80,3 +80,4 @@ stable kernels.
 | Qualcomm Tech. | Falkor v1       | E1009           | 
QCOM_FALKOR_ERRATUM_1009    |
 | Qualcomm Tech. | QDF2400 ITS     | E0065           | 
QCOM_QDF2400_ERRATUM_0065   |
 | Qualcomm Tech. | Falkor v{1,2}   | E1041           | 
QCOM_FALKOR_ERRATUM_1041    |
+| Fujitsu        | A64FX           | E#010001        | FUJITSU_ERRATUM_010001  
    |
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a4168d3..9c09b2b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -643,6 +643,19 @@ config QCOM_FALKOR_ERRATUM_E1041
 
          If unsure, say Y.
 
+config FUJITSU_ERRATUM_010001
+       bool "Fujitsu-A64FX erratum E#010001: Undefined fault may occur wrongly"
+       default y
+       help
+         This option adds workaround for Fujitsu-A64FX erratum E#010001.
+         On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1), memory 
accesses
+         may cause undefined fault (Data abort, DFSC=0b111111).
+         The workaround is to replace the fault handler for Data abort 
DFSC=0b111111
+         with a new one to ignore this undefined fault, which will only affect
+         the Fujitsu-A64FX.
+
+         If unsure, say Y.
+
 endmenu
 
 
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 82e9099..3a0b375 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -60,7 +60,8 @@
 #define ARM64_HAS_ADDRESS_AUTH_IMP_DEF         39
 #define ARM64_HAS_GENERIC_AUTH_ARCH            40
 #define ARM64_HAS_GENERIC_AUTH_IMP_DEF         41
+#define ARM64_WORKAROUND_FUJITSU_A64FX_0100001 42
 
-#define ARM64_NCAPS                            42
+#define ARM64_NCAPS                            43
 
 #endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h
index 951ed1a..70203f9 100644
--- a/arch/arm64/include/asm/cputype.h
+++ b/arch/arm64/include/asm/cputype.h
@@ -76,6 +76,7 @@
 #define ARM_CPU_IMP_BRCM               0x42
 #define ARM_CPU_IMP_QCOM               0x51
 #define ARM_CPU_IMP_NVIDIA             0x4E
+#define ARM_CPU_IMP_FUJITSU            0x46
 
 #define ARM_CPU_PART_AEM_V8            0xD0F
 #define ARM_CPU_PART_FOUNDATION                0xD00
@@ -104,6 +105,8 @@
 #define NVIDIA_CPU_PART_DENVER         0x003
 #define NVIDIA_CPU_PART_CARMEL         0x004
 
+#define FUJITSU_CPU_PART_A64FX         0x001
+
 #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, 
ARM_CPU_PART_CORTEX_A53)
 #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, 
ARM_CPU_PART_CORTEX_A57)
 #define MIDR_CORTEX_A72 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, 
ARM_CPU_PART_CORTEX_A72)
@@ -122,6 +125,7 @@
 #define MIDR_QCOM_KRYO MIDR_CPU_MODEL(ARM_CPU_IMP_QCOM, QCOM_CPU_PART_KRYO)
 #define MIDR_NVIDIA_DENVER MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, 
NVIDIA_CPU_PART_DENVER)
 #define MIDR_NVIDIA_CARMEL MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, 
NVIDIA_CPU_PART_CARMEL)
+#define MIDR_FUJITSU_A64FX MIDR_CPU_MODEL(ARM_CPU_IMP_FUJITSU, 
FUJITSU_CPU_PART_A64FX)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 9950bb0..fc0737f 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -739,6 +739,14 @@ static bool has_ssbd_mitigation(const struct 
arm64_cpu_capabilities *entry,
                ERRATA_MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0),
        },
 #endif
+#ifdef CONFIG_FUJITSU_ERRATUM_010001
+       {
+               .desc = "Fujitsu erratum 010001",
+               .capability = ARM64_WORKAROUND_FUJITSU_A64FX_0100001,
+               ERRATA_MIDR_RANGE(MIDR_FUJITSU_A64FX, 0, 0, 1, 0),
+       },
+#endif
+
        {
        }
 };
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index efb7b2c..37e4f18 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -666,6 +666,28 @@ static int do_sea(unsigned long addr, unsigned int esr, 
struct pt_regs *regs)
        return 0;
 }
 
+static int do_bad_unknown_63(unsigned long addr, unsigned int esr, struct 
pt_regs *regs)
+{
+       /*
+        * On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1),
+        * memory accesses may spuriously trigger data aborts with
+        * DFSC=0b111111.
+        */
+       if (IS_ENABLED(CONFIG_FUJITSU_ERRATUM_010001)) {
+               if (cpus_have_cap(ARM64_WORKAROUND_FUJITSU_A64FX_0100001)) {
+                       return 0;
+               } else { /* cpu capabilities maybe not ready*/
+                       unsigned int current_cpu_midr = read_cpuid_id();
+                       const struct midr_range fujitsu_a64fx_midr_range = {
+                               MIDR_FUJITSU_A64FX, MIDR_CPU_VAR_REV(0, 0), 
MIDR_CPU_VAR_REV(1, 0)
+                       };
+                       if (is_midr_in_range(current_cpu_midr, 
&fujitsu_a64fx_midr_range) == TRUE)
+                               return 0;
+               }
+       }
+       return do_bad(addr, esr, regs);
+}
+
 static const struct fault_info fault_info[] = {
        { do_bad,               SIGKILL, SI_KERNEL,     "ttbr address size 
fault"       },
        { do_bad,               SIGKILL, SI_KERNEL,     "level 1 address size 
fault"    },
@@ -730,7 +752,7 @@ static int do_sea(unsigned long addr, unsigned int esr, 
struct pt_regs *regs)
        { do_bad,               SIGKILL, SI_KERNEL,     "unknown 60"            
        },
        { do_bad,               SIGKILL, SI_KERNEL,     "section domain fault"  
        },
        { do_bad,               SIGKILL, SI_KERNEL,     "page domain fault"     
        },
-       { do_bad,               SIGKILL, SI_KERNEL,     "unknown 63"            
        },
+       { do_bad_unknown_63,    SIGKILL, SI_KERNEL,     "unknown 63"            
        },
 };
 
 int handle_guest_sea(phys_addr_t addr, unsigned int esr)
-- 
1.8.3.1

Reply via email to