From 800149a77c2cb8746a94457939b1ba1e37d2c14e Mon Sep 17 00:00:00 2001 From: Vincent Chen Date: Mon, 22 Mar 2021 22:26:05 +0800 Subject: [PATCH] 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 Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig.erratas | 11 +++++++++ arch/riscv/errata/sifive/Makefile | 1 + arch/riscv/errata/sifive/errata.c | 20 ++++++++++++++++ arch/riscv/errata/sifive/errata_cip_453.S | 38 +++++++++++++++++++++++++++++++ arch/riscv/include/asm/errata_list.h | 21 ++++++++++++++++- arch/riscv/kernel/entry.S | 6 +++-- 6 files changed, 94 insertions(+), 3 deletions(-) create mode 100644 arch/riscv/errata/sifive/errata_cip_453.S diff --git a/arch/riscv/Kconfig.erratas b/arch/riscv/Kconfig.erratas index 302e746..b4146dc 100644 --- a/arch/riscv/Kconfig.erratas +++ b/arch/riscv/Kconfig.erratas @@ -19,4 +19,15 @@ config ERRATA_SIFIVE Otherwise, please say "N" here to avoid unnecessary overhead. +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". + endmenu diff --git a/arch/riscv/errata/sifive/Makefile b/arch/riscv/errata/sifive/Makefile index 2d644e1..bdd5fc8 100644 --- a/arch/riscv/errata/sifive/Makefile +++ b/arch/riscv/errata/sifive/Makefile @@ -1 +1,2 @@ +obj-y += errata_cip_453.o obj-y += errata.o diff --git a/arch/riscv/errata/sifive/errata.c b/arch/riscv/errata/sifive/errata.c index 826cd39..e273918 100644 --- a/arch/riscv/errata/sifive/errata.c +++ b/arch/riscv/errata/sifive/errata.c @@ -16,6 +16,26 @@ struct errata_info_t { bool (*check_func)(unsigned long arch_id, unsigned long impid); }; +static bool errata_cip_453_check_func(unsigned long arch_id, unsigned long impid) +{ + /* + * Affected cores: + * Architecture ID: 0x8000000000000007 + * Implement ID: 0x20181004 <= impid <= 0x20191105 + */ + if (arch_id != 0x8000000000000007 || + (impid < 0x20181004 || impid > 0x20191105)) + return false; + return true; +} + +static struct errata_info_t errata_list[ERRATA_SIFIVE_NUMBER] = { + { + .name = "cip-453", + .check_func = errata_cip_453_check_func + }, +}; + static u32 __init sifive_errata_probe(unsigned long archid, unsigned long impid) { int idx; diff --git a/arch/riscv/errata/sifive/errata_cip_453.S b/arch/riscv/errata/sifive/errata_cip_453.S new file mode 100644 index 0000000..f1b9623 --- /dev/null +++ b/arch/riscv/errata/sifive/errata_cip_453.S @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2021 SiFive + */ + +#include +#include +#include +#include + +.macro ADD_SIGN_EXT pt_reg badaddr tmp_reg + REG_L \badaddr, PT_BADADDR(\pt_reg) + li \tmp_reg,1 + slli \tmp_reg,\tmp_reg,0x26 + and \tmp_reg,\tmp_reg,\badaddr + beqz \tmp_reg, 1f + li \tmp_reg,-1 + slli \tmp_reg,\tmp_reg,0x27 + or \badaddr,\tmp_reg,\badaddr + REG_S \badaddr, PT_BADADDR(\pt_reg) +1: +.endm + +ENTRY(sifive_cip_453_page_fault_trp) + ADD_SIGN_EXT a0, t0, t1 +#ifdef CONFIG_MMU + la t0, do_page_fault +#else + la t0, do_trap_unknown +#endif + jr t0 +END(sifive_cip_453_page_fault_trp) + +ENTRY(sifive_cip_453_insn_fault_trp) + ADD_SIGN_EXT a0, t0, t1 + la t0, do_trap_insn_fault + jr t0 +END(sifive_cip_453_insn_fault_trp) diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h index 1b56131..6148d34 100644 --- a/arch/riscv/include/asm/errata_list.h +++ b/arch/riscv/include/asm/errata_list.h @@ -5,8 +5,27 @@ #ifndef ASM_ERRATA_LIST_H #define ASM_ERRATA_LIST_H +#include +#include + #ifdef CONFIG_ERRATA_SIFIVE -#define ERRATA_SIFIVE_NUMBER 0 +#define ERRATA_SIFIVE_CIP_453 0 +#define ERRATA_SIFIVE_NUMBER 1 #endif +#ifdef __ASSEMBLY__ + +#define ALT_INSN_FAULT(x) \ +ALTERNATIVE(__stringify(RISCV_PTR do_trap_insn_fault), \ + __stringify(RISCV_PTR sifive_cip_453_insn_fault_trp), \ + SIFIVE_VENDOR_ID, ERRATA_SIFIVE_CIP_453, \ + CONFIG_ERRATA_SIFIVE_CIP_453) + +#define ALT_PAGE_FAULT(x) \ +ALTERNATIVE(__stringify(RISCV_PTR do_page_fault), \ + __stringify(RISCV_PTR sifive_cip_453_page_fault_trp), \ + SIFIVE_VENDOR_ID, ERRATA_SIFIVE_CIP_453, \ + CONFIG_ERRATA_SIFIVE_CIP_453) +#endif /* __ASSEMBLY__ */ + #endif diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 744f320..60d0a2f 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -12,6 +12,7 @@ #include #include #include +#include #if !IS_ENABLED(CONFIG_PREEMPTION) .set resume_kernel, restore_all @@ -450,7 +451,7 @@ ENDPROC(__switch_to) /* Exception vector table */ ENTRY(excp_vect_table) RISCV_PTR do_trap_insn_misaligned - RISCV_PTR do_trap_insn_fault + ALT_INSN_FAULT(RISCV_PTR do_trap_insn_fault) RISCV_PTR do_trap_insn_illegal RISCV_PTR do_trap_break RISCV_PTR do_trap_load_misaligned @@ -461,7 +462,8 @@ ENTRY(excp_vect_table) RISCV_PTR do_trap_ecall_s RISCV_PTR do_trap_unknown RISCV_PTR do_trap_ecall_m - RISCV_PTR do_page_fault /* instruction page fault */ + /* instruciton page fault */ + ALT_PAGE_FAULT(RISCV_PTR do_page_fault) RISCV_PTR do_page_fault /* load page fault */ RISCV_PTR do_trap_unknown RISCV_PTR do_page_fault /* store page fault */ -- 2.7.4