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OpenCloudOS-Kernel/arch/riscv/Kconfig.erratas

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riscv: Introduce alternative mechanism to apply errata solution Introduce the "alternative" mechanism from ARM64 and x86 to apply the CPU vendors' errata solution at runtime. The main purpose of this patch is to provide a framework. Therefore, the implementation is quite basic for now so that some scenarios could not use this schemei, such as patching code to a module, relocating the patching code and heterogeneous CPU topology. Users could use the macro ALTERNATIVE to apply an errata to the existing code flow. In the macro ALTERNATIVE, users need to specify the manufacturer information(vendorid, archid, and impid) for this errata. Therefore, kernel will know this errata is suitable for which CPU core. During the booting procedure, kernel will select the errata required by the CPU core and then patch it. It means that the kernel only applies the errata to the specified CPU core. In this case, the vendor's errata does not affect each other at runtime. The above patching procedure only occurs during the booting phase, so we only take the overhead of the "alternative" mechanism once. This "alternative" mechanism is enabled by default to ensure that all required errata will be applied. However, users can disable this feature by the Kconfig "CONFIG_RISCV_ERRATA_ALTERNATIVE". Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-03-22 22:26:03 +08:00
menu "CPU errata selection"
config RISCV_ERRATA_ALTERNATIVE
bool "RISC-V alternative scheme"
default y
help
This Kconfig allows the kernel to automatically patch the
errata required by the execution platform at run time. The
code patching is performed once in the boot stages. It means
that the overhead from this mechanism is just taken once.
riscv: sifive: Add SiFive alternative ports Add required ports of the Alternative scheme for SiFive. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-03-22 22:26:04 +08:00
config ERRATA_SIFIVE
bool "SiFive errata"
depends on RISCV_ERRATA_ALTERNATIVE
help
All SiFive errata Kconfig depend on this Kconfig. Disabling
this Kconfig will disable all SiFive errata. Please say "Y"
here if your platform uses SiFive CPU cores.
Otherwise, please say "N" here to avoid unnecessary overhead.
riscv: sifive: Apply errata "cip-453" patch Add sign extension to the $badaddr before addressing the instruction page fault and instruction access fault to workaround the issue "cip-453". To avoid affecting the existing code sequence, this patch will creates two trampolines to add sign extension to the $badaddr. By the "alternative" mechanism, these two trampolines will replace the original exception handler of instruction page fault and instruction access fault in the excp_vect_table. In this case, only the specific SiFive CPU core jumps to the do_page_fault and do_trap_insn_fault through these two trampolines. Other CPUs are not affected. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-03-22 22:26:05 +08:00
config ERRATA_SIFIVE_CIP_453
bool "Apply SiFive errata CIP-453"
depends on ERRATA_SIFIVE
default y
help
This will apply the SiFive CIP-453 errata to add sign extension
to the $badaddr when exception type is instruction page fault
and instruction access fault.
If you don't know what to do here, say "Y".
riscv: Introduce alternative mechanism to apply errata solution Introduce the "alternative" mechanism from ARM64 and x86 to apply the CPU vendors' errata solution at runtime. The main purpose of this patch is to provide a framework. Therefore, the implementation is quite basic for now so that some scenarios could not use this schemei, such as patching code to a module, relocating the patching code and heterogeneous CPU topology. Users could use the macro ALTERNATIVE to apply an errata to the existing code flow. In the macro ALTERNATIVE, users need to specify the manufacturer information(vendorid, archid, and impid) for this errata. Therefore, kernel will know this errata is suitable for which CPU core. During the booting procedure, kernel will select the errata required by the CPU core and then patch it. It means that the kernel only applies the errata to the specified CPU core. In this case, the vendor's errata does not affect each other at runtime. The above patching procedure only occurs during the booting phase, so we only take the overhead of the "alternative" mechanism once. This "alternative" mechanism is enabled by default to ensure that all required errata will be applied. However, users can disable this feature by the Kconfig "CONFIG_RISCV_ERRATA_ALTERNATIVE". Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-03-22 22:26:03 +08:00
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