From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> This patch is added just for building purpose, as patch [0] will export this in its next version. https://patchwork.kernel.org/project/linux-riscv/patch/20221110164924.529386-6-heiko@xxxxxxxxx/ Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> --- Note, as Heiko will be exporting riscv_alternative_fix_auipc_jalr() function so that it can be used other erratas Ive just included for compilation. --- arch/riscv/errata/andes/errata.c | 71 ++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/arch/riscv/errata/andes/errata.c b/arch/riscv/errata/andes/errata.c index ec3e052ca8c7..4061ad4983bc 100644 --- a/arch/riscv/errata/andes/errata.c +++ b/arch/riscv/errata/andes/errata.c @@ -13,9 +13,80 @@ #include <asm/alternative.h> #include <asm/cacheflush.h> #include <asm/errata_list.h> +#include <asm/parse_asm.h> #include <asm/patch.h> +#include <asm/sbi.h> #include <asm/vendorid_list.h> +/* Copy of Heiko's code from patch [0] + * [0] https://patchwork.kernel.org/project/linux-riscv/patch/20221110164924.529386-6-heiko@xxxxxxxxx/ + */ +DECLARE_INSN(jalr, MATCH_JALR, MASK_JALR) +DECLARE_INSN(auipc, MATCH_AUIPC, MASK_AUIPC) + +static inline bool is_auipc_jalr_pair(long insn1, long insn2) +{ + return is_auipc_insn(insn1) && is_jalr_insn(insn2); +} + +#define JALR_SIGN_MASK BIT(I_IMM_SIGN_OPOFF - I_IMM_11_0_OPOFF) +#define JALR_OFFSET_MASK I_IMM_11_0_MASK +#define AUIPC_OFFSET_MASK U_IMM_31_12_MASK +#define AUIPC_PAD (0x00001000) +#define JALR_SHIFT I_IMM_11_0_OPOFF + +#define to_jalr_imm(offset) \ + ((offset & I_IMM_11_0_MASK) << I_IMM_11_0_OPOFF) + +#define to_auipc_imm(offset) \ + ((offset & JALR_SIGN_MASK) ? \ + ((offset & AUIPC_OFFSET_MASK) + AUIPC_PAD) : \ + (offset & AUIPC_OFFSET_MASK)) + +static void riscv_alternative_fix_auipc_jalr(unsigned int *alt_ptr, + unsigned int len, int patch_offset) +{ + int num_instr = len / sizeof(u32); + unsigned int call[2]; + int i; + int imm1; + u32 rd1; + + for (i = 0; i < num_instr; i++) { + /* is there a further instruction? */ + if (i + 1 >= num_instr) + continue; + + if (!is_auipc_jalr_pair(*(alt_ptr + i), *(alt_ptr + i + 1))) + continue; + + /* call will use ra register */ + rd1 = EXTRACT_RD_REG(*(alt_ptr + i)); + if (rd1 != 1) + continue; + + /* get and adjust new target address */ + imm1 = EXTRACT_UTYPE_IMM(*(alt_ptr + i)); + imm1 += EXTRACT_ITYPE_IMM(*(alt_ptr + i + 1)); + imm1 -= patch_offset; + + /* pick the original auipc + jalr */ + call[0] = *(alt_ptr + i); + call[1] = *(alt_ptr + i + 1); + + /* drop the old IMMs */ + call[0] &= ~(U_IMM_31_12_MASK); + call[1] &= ~(I_IMM_11_0_MASK << I_IMM_11_0_OPOFF); + + /* add the adapted IMMs */ + call[0] |= to_auipc_imm(imm1); + call[1] |= to_jalr_imm(imm1); + + /* patch the call place again */ + patch_text_nosync(alt_ptr + i, call, 8); + } +} + static bool errata_probe_iocp(unsigned int stage, unsigned long arch_id, unsigned long impid) { if (!IS_ENABLED(CONFIG_ERRATA_ANDES_CMO)) -- 2.25.1
