Hi, Sorry, I've posted a wrong patch which causes the compilation errors. Please disregard this patch, I posted v3 patch to fix the build issue. https://patchwork.kernel.org/patch/10055077/ On 11/12/2017 07:16 PM, Shanker Donthineni wrote: > The ARM architecture defines the memory locations that are permitted > to be accessed as the result of a speculative instruction fetch from > an exception level for which all stages of translation are disabled. > Specifically, the core is permitted to speculatively fetch from the > 4KB region containing the current program counter 4K and next 4K. > > When translation is changed from enabled to disabled for the running > exception level (SCTLR_ELn[M] changed from a value of 1 to 0), the > Falkor core may errantly speculatively access memory locations outside > of the 4KB region permitted by the architecture. The errant memory > access may lead to one of the following unexpected behaviors. > > 1) A System Error Interrupt (SEI) being raised by the Falkor core due > to the errant memory access attempting to access a region of memory > that is protected by a slave-side memory protection unit. > 2) Unpredictable device behavior due to a speculative read from device > memory. This behavior may only occur if the instruction cache is > disabled prior to or coincident with translation being changed from > enabled to disabled. > > The conditions leading to this erratum will not occur when either of the > following occur: > 1) A higher exception level disables translation of a lower exception level > (e.g. EL2 changing SCTLR_EL1[M] from a value of 1 to 0). > 2) An exception level disabling its stage-1 translation if its stage-2 > translation is enabled (e.g. EL1 changing SCTLR_EL1[M] from a value of 1 > to 0 when HCR_EL2[VM] has a value of 1). > > To avoid the errant behavior, software must execute an ISB immediately > prior to executing the MSR that will change SCTLR_ELn[M] from 1 to 0. > > Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> > --- > Documentation/arm64/silicon-errata.txt | 1 + > arch/arm64/Kconfig | 10 ++++++++++ > arch/arm64/include/asm/assembler.h | 18 ++++++++++++++++++ > arch/arm64/include/asm/cpucaps.h | 3 ++- > arch/arm64/kernel/cpu-reset.S | 1 + > arch/arm64/kernel/cpu_errata.c | 16 ++++++++++++++++ > arch/arm64/kernel/efi-entry.S | 2 ++ > arch/arm64/kernel/head.S | 1 + > arch/arm64/kernel/relocate_kernel.S | 1 + > arch/arm64/kvm/hyp-init.S | 1 + > 10 files changed, 53 insertions(+), 1 deletion(-) > > diff --git a/Documentation/arm64/silicon-errata.txt b/Documentation/arm64/silicon-errata.txt > index 66e8ce1..704770c0 100644 > --- a/Documentation/arm64/silicon-errata.txt > +++ b/Documentation/arm64/silicon-errata.txt > @@ -74,3 +74,4 @@ stable kernels. > | Qualcomm Tech. | Falkor v1 | E1003 | QCOM_FALKOR_ERRATUM_1003 | > | 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 | > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 0df64a6..8f73eac 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -539,6 +539,16 @@ config QCOM_QDF2400_ERRATUM_0065 > > If unsure, say Y. > > +config QCOM_FALKOR_ERRATUM_E1041 > + bool "Falkor E1041: Speculative instruction fetches might cause errant memory access" > + default y > + help > + Falkor CPU may speculatively fetch instructions from an improper > + memory location when MMU translation is changed from SCTLR_ELn[M]=1 > + to SCTLR_ELn[M]=0. Prefix an ISB instruction to fix the problem. > + > + If unsure, say Y. > + > endmenu > > > diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h > index d58a625..eb11cdf 100644 > --- a/arch/arm64/include/asm/assembler.h > +++ b/arch/arm64/include/asm/assembler.h > @@ -499,4 +499,22 @@ > #endif > .endm > > +/** > + * Errata workaround prior to disable MMU. Insert an ISB immediately prior > + * to executing the MSR that will change SCTLR_ELn[M] from a value of 1 to 0. > + */ > + .macro pre_disable_mmu_workaround > +#ifdef CONFIG_QCOM_FALKOR_ERRATUM_E1041 > +alternative_if ARM64_WORKAROUND_QCOM_FALKOR_E1041 > + isb > +alternative_else_nop_endif > +#endif > + .end > + > + .macro pre_disable_mmu_early_workaround > +#ifdef CONFIG_QCOM_FALKOR_ERRATUM_E1041 > + isb > +#endif > + .end > + > #endif /* __ASM_ASSEMBLER_H */ > diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h > index 8da6216..7f7a59d 100644 > --- a/arch/arm64/include/asm/cpucaps.h > +++ b/arch/arm64/include/asm/cpucaps.h > @@ -40,7 +40,8 @@ > #define ARM64_WORKAROUND_858921 19 > #define ARM64_WORKAROUND_CAVIUM_30115 20 > #define ARM64_HAS_DCPOP 21 > +#define ARM64_WORKAROUND_QCOM_FALKOR_E1041 22 > > -#define ARM64_NCAPS 22 > +#define ARM64_NCAPS 23 > > #endif /* __ASM_CPUCAPS_H */ > diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S > index 65f42d2..2a752cb 100644 > --- a/arch/arm64/kernel/cpu-reset.S > +++ b/arch/arm64/kernel/cpu-reset.S > @@ -37,6 +37,7 @@ ENTRY(__cpu_soft_restart) > mrs x12, sctlr_el1 > ldr x13, =SCTLR_ELx_FLAGS > bic x12, x12, x13 > + pre_disable_mmu_workaround > msr sctlr_el1, x12 > isb > > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > index 0e27f86..2fd1938 100644 > --- a/arch/arm64/kernel/cpu_errata.c > +++ b/arch/arm64/kernel/cpu_errata.c > @@ -179,6 +179,22 @@ static int cpu_enable_trap_ctr_access(void *__unused) > MIDR_CPU_VAR_REV(0, 0)), > }, > #endif > +#ifdef CONFIG_QCOM_FALKOR_ERRATUM_E1041 > + { > + .desc = "Qualcomm Technologies Falkor erratum 1041", > + .capability = ARM64_WORKAROUND_QCOM_FALKOR_E1041, > + MIDR_RANGE(MIDR_QCOM_FALKOR_V1, > + MIDR_CPU_VAR_REV(0, 0), > + MIDR_CPU_VAR_REV(0, 0)), > + }, > + { > + .desc = "Qualcomm Technologies Falkor erratum 1041", > + .capability = ARM64_WORKAROUND_QCOM_FALKOR_E1041, > + MIDR_RANGE(MIDR_QCOM_FALKOR, > + MIDR_CPU_VAR_REV(0, 1), > + MIDR_CPU_VAR_REV(0, 2)), > + }, > +#endif > #ifdef CONFIG_ARM64_ERRATUM_858921 > { > /* Cortex-A73 all versions */ > diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S > index 4e6ad35..dc675ba 100644 > --- a/arch/arm64/kernel/efi-entry.S > +++ b/arch/arm64/kernel/efi-entry.S > @@ -96,6 +96,7 @@ ENTRY(entry) > mrs x0, sctlr_el2 > bic x0, x0, #1 << 0 // clear SCTLR.M > bic x0, x0, #1 << 2 // clear SCTLR.C > + pre_disable_mmu_early_workaround > msr sctlr_el2, x0 > isb > b 2f > @@ -103,6 +104,7 @@ ENTRY(entry) > mrs x0, sctlr_el1 > bic x0, x0, #1 << 0 // clear SCTLR.M > bic x0, x0, #1 << 2 // clear SCTLR.C > + pre_disable_mmu_early_workaround > msr sctlr_el1, x0 > isb > 2: > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 0b243ec..a807fca 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -732,6 +732,7 @@ __primary_switch: > * to take into account by discarding the current kernel mapping and > * creating a new one. > */ > + pre_disable_mmu_early_workaround > msr sctlr_el1, x20 // disable the MMU > isb > bl __create_page_tables // recreate kernel mapping > diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S > index ce704a4..f407e42 100644 > --- a/arch/arm64/kernel/relocate_kernel.S > +++ b/arch/arm64/kernel/relocate_kernel.S > @@ -45,6 +45,7 @@ ENTRY(arm64_relocate_new_kernel) > mrs x0, sctlr_el2 > ldr x1, =SCTLR_ELx_FLAGS > bic x0, x0, x1 > + pre_disable_mmu_workaround > msr sctlr_el2, x0 > isb > 1: > diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S > index 3f96155..870828c 100644 > --- a/arch/arm64/kvm/hyp-init.S > +++ b/arch/arm64/kvm/hyp-init.S > @@ -151,6 +151,7 @@ reset: > mrs x5, sctlr_el2 > ldr x6, =SCTLR_ELx_FLAGS > bic x5, x5, x6 // Clear SCTL_M and etc > + pre_disable_mmu_workaround > msr sctlr_el2, x5 > isb > > -- Shanker Donthineni Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. 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