--- /dev/null
+From ece1397cbc89c51914fae1aec729539cfd8bd62b Mon Sep 17 00:00:00 2001
+From: Suzuki K Poulose <suzuki.poulose@arm.com>
+Date: Mon, 26 Mar 2018 15:12:49 +0100
+Subject: arm64: Add work around for Arm Cortex-A55 Erratum 1024718
+
+From: Suzuki K Poulose <suzuki.poulose@arm.com>
+
+commit ece1397cbc89c51914fae1aec729539cfd8bd62b upstream.
+
+Some variants of the Arm Cortex-55 cores (r0p0, r0p1, r1p0) suffer
+from an erratum 1024718, which causes incorrect updates when DBM/AP
+bits in a page table entry is modified without a break-before-make
+sequence. The work around is to skip enabling the hardware DBM feature
+on the affected cores. The hardware Access Flag management features
+is not affected. There are some other cores suffering from this
+errata, which could be added to the midr_list to trigger the work
+around.
+
+Cc: Catalin Marinas <catalin.marinas@arm.com>
+Cc: ckadabi@codeaurora.org
+Reviewed-by: Dave Martin <dave.martin@arm.com>
+Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
+Signed-off-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ Documentation/arm64/silicon-errata.txt | 1
+ arch/arm64/Kconfig | 14 +++++++++++
+ arch/arm64/include/asm/assembler.h | 40 +++++++++++++++++++++++++++++++++
+ arch/arm64/include/asm/cputype.h | 2 +
+ arch/arm64/mm/proc.S | 5 ++++
+ 5 files changed, 62 insertions(+)
+
+--- a/Documentation/arm64/silicon-errata.txt
++++ b/Documentation/arm64/silicon-errata.txt
+@@ -55,6 +55,7 @@ stable kernels.
+ | ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 |
+ | ARM | Cortex-A72 | #853709 | N/A |
+ | ARM | Cortex-A73 | #858921 | ARM64_ERRATUM_858921 |
++| ARM | Cortex-A55 | #1024718 | ARM64_ERRATUM_1024718 |
+ | ARM | MMU-500 | #841119,#826419 | N/A |
+ | | | | |
+ | Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 |
+--- a/arch/arm64/Kconfig
++++ b/arch/arm64/Kconfig
+@@ -443,6 +443,20 @@ config ARM64_ERRATUM_843419
+
+ If unsure, say Y.
+
++config ARM64_ERRATUM_1024718
++ bool "Cortex-A55: 1024718: Update of DBM/AP bits without break before make might result in incorrect update"
++ default y
++ help
++ This option adds work around for Arm Cortex-A55 Erratum 1024718.
++
++ Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
++ update of the hardware dirty bit when the DBM/AP bits are updated
++ without a break-before-make. The work around is to disable the usage
++ of hardware DBM locally on the affected cores. CPUs not affected by
++ erratum will continue to use the feature.
++
++ If unsure, say Y.
++
+ config CAVIUM_ERRATUM_22375
+ bool "Cavium erratum 22375, 24313"
+ default y
+--- a/arch/arm64/include/asm/assembler.h
++++ b/arch/arm64/include/asm/assembler.h
+@@ -25,6 +25,7 @@
+
+ #include <asm/asm-offsets.h>
+ #include <asm/cpufeature.h>
++#include <asm/cputype.h>
+ #include <asm/page.h>
+ #include <asm/pgtable-hwdef.h>
+ #include <asm/ptrace.h>
+@@ -495,4 +496,43 @@ alternative_endif
+ and \phys, \pte, #(((1 << (48 - PAGE_SHIFT)) - 1) << PAGE_SHIFT)
+ .endm
+
++/*
++ * Check the MIDR_EL1 of the current CPU for a given model and a range of
++ * variant/revision. See asm/cputype.h for the macros used below.
++ *
++ * model: MIDR_CPU_MODEL of CPU
++ * rv_min: Minimum of MIDR_CPU_VAR_REV()
++ * rv_max: Maximum of MIDR_CPU_VAR_REV()
++ * res: Result register.
++ * tmp1, tmp2, tmp3: Temporary registers
++ *
++ * Corrupts: res, tmp1, tmp2, tmp3
++ * Returns: 0, if the CPU id doesn't match. Non-zero otherwise
++ */
++ .macro cpu_midr_match model, rv_min, rv_max, res, tmp1, tmp2, tmp3
++ mrs \res, midr_el1
++ mov_q \tmp1, (MIDR_REVISION_MASK | MIDR_VARIANT_MASK)
++ mov_q \tmp2, MIDR_CPU_MODEL_MASK
++ and \tmp3, \res, \tmp2 // Extract model
++ and \tmp1, \res, \tmp1 // rev & variant
++ mov_q \tmp2, \model
++ cmp \tmp3, \tmp2
++ cset \res, eq
++ cbz \res, .Ldone\@ // Model matches ?
++
++ .if (\rv_min != 0) // Skip min check if rv_min == 0
++ mov_q \tmp3, \rv_min
++ cmp \tmp1, \tmp3
++ cset \res, ge
++ .endif // \rv_min != 0
++ /* Skip rv_max check if rv_min == rv_max && rv_min != 0 */
++ .if ((\rv_min != \rv_max) || \rv_min == 0)
++ mov_q \tmp2, \rv_max
++ cmp \tmp1, \tmp2
++ cset \tmp2, le
++ and \res, \res, \tmp2
++ .endif
++.Ldone\@:
++ .endm
++
+ #endif /* __ASM_ASSEMBLER_H */
+--- a/arch/arm64/include/asm/cputype.h
++++ b/arch/arm64/include/asm/cputype.h
+@@ -78,6 +78,7 @@
+
+ #define ARM_CPU_PART_AEM_V8 0xD0F
+ #define ARM_CPU_PART_FOUNDATION 0xD00
++#define ARM_CPU_PART_CORTEX_A55 0xD05
+ #define ARM_CPU_PART_CORTEX_A57 0xD07
+ #define ARM_CPU_PART_CORTEX_A72 0xD08
+ #define ARM_CPU_PART_CORTEX_A53 0xD03
+@@ -98,6 +99,7 @@
+ #define QCOM_CPU_PART_KRYO 0x200
+
+ #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
++#define MIDR_CORTEX_A55 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A55)
+ #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)
+ #define MIDR_CORTEX_A73 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A73)
+--- a/arch/arm64/mm/proc.S
++++ b/arch/arm64/mm/proc.S
+@@ -438,6 +438,11 @@ ENTRY(__cpu_setup)
+ cbz x9, 2f
+ cmp x9, #2
+ b.lt 1f
++#ifdef CONFIG_ARM64_ERRATUM_1024718
++ /* Disable hardware DBM on Cortex-A55 r0p0, r0p1 & r1p0 */
++ cpu_midr_match MIDR_CORTEX_A55, MIDR_CPU_VAR_REV(0, 0), MIDR_CPU_VAR_REV(1, 0), x1, x2, x3, x4
++ cbnz x1, 1f
++#endif
+ orr x10, x10, #TCR_HD // hardware Dirty flag update
+ 1: orr x10, x10, #TCR_HA // hardware Access flag update
+ 2:
projects / thirdparty / kernel / stable-queue.git / commitdiff
