From 6f4eea90465ad0cd5f3d041b9b2c728426f2b8d4 Mon Sep 17 00:00:00 2001 From: Vincent Chen Date: Mon, 22 Mar 2021 22:26:03 +0800 Subject: 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 Reviewed-by: Anup Patel Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/errata_list.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 arch/riscv/include/asm/errata_list.h (limited to 'arch/riscv/include/asm/errata_list.h') diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h new file mode 100644 index 000000000000..1b56131431c9 --- /dev/null +++ b/arch/riscv/include/asm/errata_list.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2021 Sifive. + */ +#ifndef ASM_ERRATA_LIST_H +#define ASM_ERRATA_LIST_H + +#ifdef CONFIG_ERRATA_SIFIVE +#define ERRATA_SIFIVE_NUMBER 0 +#endif + +#endif -- cgit v1.2.3