From a512242e66cea3de1020d83ca9f2977c0a75530b Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Tue, 19 Oct 2021 17:31:41 +0100 Subject: [PATCH] BACKPORT: arm64: errata: Add workaround for TSB flush failures Arm Neoverse-N2 (#2067961) and Cortex-A710 (#2054223) suffers from errata, where a TSB (trace synchronization barrier) fails to flush the trace data completely, when executed from a trace prohibited region. In Linux we always execute it after we have moved the PE to trace prohibited region. So, we can apply the workaround every time a TSB is executed. The work around is to issue two TSB consecutively. NOTE: This errata is defined as LOCAL_CPU_ERRATUM, implying that a late CPU could be blocked from booting if it is the first CPU that requires the workaround. This is because we do not allow setting a cpu_hwcaps after the SMP boot. The other alternative is to use "this_cpu_has_cap()" instead of the faster system wide check, which may be a bit of an overhead, given we may have to do this in nvhe KVM host before a guest entry. Bug: 213931796 Cc: Will Deacon Cc: Catalin Marinas Cc: Mathieu Poirier Cc: Mike Leach Cc: Mark Rutland Cc: Anshuman Khandual Cc: Marc Zyngier Acked-by: Catalin Marinas Reviewed-by: Mathieu Poirier Reviewed-by: Anshuman Khandual Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20211019163153.3692640-4-suzuki.poulose@arm.com Signed-off-by: Will Deacon (cherry picked from commit fa82d0b4b833790ac4572377fb777dcea24a9d69) [Fix conflict due to another workaround that is not backported (TRBE_OVERWRITE). Also manually update cpucaps.h which is autogenerated in upstream from arch/arm64/tools/cpucaps which we ignored as part of the conflict resolution] Signed-off-by: Qais Yousef Change-Id: I6b40eaa0ac14552c867860133a04619cb556bc31 --- Documentation/arm64/silicon-errata.rst | 4 ++++ arch/arm64/Kconfig | 33 ++++++++++++++++++++++++++ arch/arm64/include/asm/barrier.h | 16 ++++++++++++- arch/arm64/include/asm/cpucaps.h | 1 + arch/arm64/kernel/cpu_errata.c | 19 +++++++++++++++ 5 files changed, 72 insertions(+), 1 deletion(-) diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst index 719510247292..5a30b1857420 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -92,12 +92,16 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | Cortex-A77 | #1508412 | ARM64_ERRATUM_1508412 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Cortex-A710 | #2054223 | ARM64_ERRATUM_2054223 | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1188873,1418040| ARM64_ERRATUM_1418040 | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1349291 | N/A | +----------------+-----------------+-----------------+-----------------------------+ | ARM | Neoverse-N1 | #1542419 | ARM64_ERRATUM_1542419 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | Neoverse-N2 | #2067961 | ARM64_ERRATUM_2067961 | ++----------------+-----------------+-----------------+-----------------------------+ | ARM | MMU-500 | #841119,826419 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +----------------+-----------------+-----------------+-----------------------------+ diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 3007e975270c..642a4482dd4e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -669,6 +669,39 @@ config ARM64_ERRATUM_1508412 If unsure, say Y. +config ARM64_WORKAROUND_TSB_FLUSH_FAILURE + bool + +config ARM64_ERRATUM_2054223 + bool "Cortex-A710: 2054223: workaround TSB instruction failing to flush trace" + default y + select ARM64_WORKAROUND_TSB_FLUSH_FAILURE + help + Enable workaround for ARM Cortex-A710 erratum 2054223 + + Affected cores may fail to flush the trace data on a TSB instruction, when + the PE is in trace prohibited state. This will cause losing a few bytes + of the trace cached. + + Workaround is to issue two TSB consecutively on affected cores. + + If unsure, say Y. + +config ARM64_ERRATUM_2067961 + bool "Neoverse-N2: 2067961: workaround TSB instruction failing to flush trace" + default y + select ARM64_WORKAROUND_TSB_FLUSH_FAILURE + help + Enable workaround for ARM Neoverse-N2 erratum 2067961 + + Affected cores may fail to flush the trace data on a TSB instruction, when + the PE is in trace prohibited state. This will cause losing a few bytes + of the trace cached. + + Workaround is to issue two TSB consecutively on affected cores. + + If unsure, say Y. + config CAVIUM_ERRATUM_22375 bool "Cavium erratum 22375, 24313" default y diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index bffa8860af1c..e9eeeb14485b 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -23,7 +23,7 @@ #define dsb(opt) asm volatile("dsb " #opt : : : "memory") #define psb_csync() asm volatile("hint #17" : : : "memory") -#define tsb_csync() asm volatile("hint #18" : : : "memory") +#define __tsb_csync() asm volatile("hint #18" : : : "memory") #define csdb() asm volatile("hint #20" : : : "memory") #define spec_bar() asm volatile(ALTERNATIVE("dsb nsh\nisb\n", \ @@ -50,6 +50,20 @@ #define dma_rmb() dmb(oshld) #define dma_wmb() dmb(oshst) + +#define tsb_csync() \ + do { \ + /* \ + * CPUs affected by Arm Erratum 2054223 or 2067961 needs \ + * another TSB to ensure the trace is flushed. The barriers \ + * don't have to be strictly back to back, as long as the \ + * CPU is in trace prohibited state. \ + */ \ + if (cpus_have_final_cap(ARM64_WORKAROUND_TSB_FLUSH_FAILURE)) \ + __tsb_csync(); \ + __tsb_csync(); \ + } while (0) + /* * Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz * and 0 otherwise. diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 10a2d914d4ca..c0ff1d4bccab 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -69,6 +69,7 @@ #define ARM64_WORKAROUND_1508412 58 #define ARM64_HAS_LDAPR 59 #define ARM64_KVM_PROTECTED_MODE 60 +#define ARM64_WORKAROUND_TSB_FLUSH_FAILURE 61 /* kabi: reserve 62 - 76 for future cpu capabilities */ #define ARM64_NCAPS 76 diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index a63428301f42..7c6d59c4f099 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -342,6 +342,18 @@ static const struct midr_range erratum_1463225[] = { }; #endif +#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE +static const struct midr_range tsb_flush_fail_cpus[] = { +#ifdef CONFIG_ARM64_ERRATUM_2067961 + MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2), +#endif +#ifdef CONFIG_ARM64_ERRATUM_2054223 + MIDR_ALL_VERSIONS(MIDR_CORTEX_A710), +#endif + {}, +}; +#endif /* CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE */ + const struct arm64_cpu_capabilities arm64_errata[] = { #ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE { @@ -527,6 +539,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { 0, 0, 1, 0), }, +#endif +#ifdef CONFIG_ARM64_WORKAROUND_TSB_FLUSH_FAILURE + { + .desc = "ARM erratum 2067961 or 2054223", + .capability = ARM64_WORKAROUND_TSB_FLUSH_FAILURE, + ERRATA_MIDR_RANGE_LIST(tsb_flush_fail_cpus), + }, #endif { }