diff options
| -rw-r--r-- | arch/riscv/include/asm/alternative.h | 3 | ||||
| -rw-r--r-- | arch/riscv/kernel/alternative.c | 56 | ||||
| -rw-r--r-- | arch/riscv/kernel/cpufeature.c | 5 |
3 files changed, 63 insertions, 1 deletions
diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h index 6511dd73e812..1bd4027d34ca 100644 --- a/arch/riscv/include/asm/alternative.h +++ b/arch/riscv/include/asm/alternative.h @@ -27,6 +27,9 @@ void __init apply_boot_alternatives(void); void __init apply_early_boot_alternatives(void); void apply_module_alternatives(void *start, size_t length); +void riscv_alternative_fix_offsets(void *alt_ptr, unsigned int len, + int patch_offset); + struct alt_entry { void *old_ptr; /* address of original instruciton or data */ void *alt_ptr; /* address of replacement instruction or data */ diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c index a7d26a00beea..6212ea0eed72 100644 --- a/arch/riscv/kernel/alternative.c +++ b/arch/riscv/kernel/alternative.c @@ -15,6 +15,8 @@ #include <asm/vendorid_list.h> #include <asm/sbi.h> #include <asm/csr.h> +#include <asm/insn.h> +#include <asm/patch.h> struct cpu_manufacturer_info_t { unsigned long vendor_id; @@ -53,6 +55,60 @@ static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_inf } } +static u32 riscv_instruction_at(void *p) +{ + u16 *parcel = p; + + return (u32)parcel[0] | (u32)parcel[1] << 16; +} + +static void riscv_alternative_fix_auipc_jalr(void *ptr, u32 auipc_insn, + u32 jalr_insn, int patch_offset) +{ + u32 call[2] = { auipc_insn, jalr_insn }; + s32 imm; + + /* get and adjust new target address */ + imm = riscv_insn_extract_utype_itype_imm(auipc_insn, jalr_insn); + imm -= patch_offset; + + /* update instructions */ + riscv_insn_insert_utype_itype_imm(&call[0], &call[1], imm); + + /* patch the call place again */ + patch_text_nosync(ptr, call, sizeof(u32) * 2); +} + +void riscv_alternative_fix_offsets(void *alt_ptr, unsigned int len, + int patch_offset) +{ + int num_insn = len / sizeof(u32); + int i; + + for (i = 0; i < num_insn; i++) { + u32 insn = riscv_instruction_at(alt_ptr + i * sizeof(u32)); + + /* + * May be the start of an auipc + jalr pair + * Needs to check that at least one more instruction + * is in the list. + */ + if (riscv_insn_is_auipc(insn) && i < num_insn - 1) { + u32 insn2 = riscv_instruction_at(alt_ptr + (i + 1) * sizeof(u32)); + + if (!riscv_insn_is_jalr(insn2)) + continue; + + /* if instruction pair is a call, it will use the ra register */ + if (RV_EXTRACT_RD_REG(insn) != 1) + continue; + + riscv_alternative_fix_auipc_jalr(alt_ptr + i * sizeof(u32), + insn, insn2, patch_offset); + } + } +} + /* * This is called very early in the boot process (directly after we run * a feature detect on the boot CPU). No need to worry about other CPUs diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 93e45560af30..205bbd6b1fce 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -339,8 +339,11 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin, } tmp = (1U << alt->errata_id); - if (cpu_req_feature & tmp) + if (cpu_req_feature & tmp) { patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len); + riscv_alternative_fix_offsets(alt->old_ptr, alt->alt_len, + alt->old_ptr - alt->alt_ptr); + } } } #endif |