diff options
Diffstat (limited to 'arch/riscv/kernel/traps_misaligned.c')
| -rw-r--r-- | arch/riscv/kernel/traps_misaligned.c | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c new file mode 100644 index 000000000..5348d842c --- /dev/null +++ b/arch/riscv/kernel/traps_misaligned.c @@ -0,0 +1,366 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 Western Digital Corporation or its affiliates. + */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/irq.h> +#include <linux/stringify.h> + +#include <asm/processor.h> +#include <asm/ptrace.h> +#include <asm/csr.h> + +#define INSN_MATCH_LB 0x3 +#define INSN_MASK_LB 0x707f +#define INSN_MATCH_LH 0x1003 +#define INSN_MASK_LH 0x707f +#define INSN_MATCH_LW 0x2003 +#define INSN_MASK_LW 0x707f +#define INSN_MATCH_LD 0x3003 +#define INSN_MASK_LD 0x707f +#define INSN_MATCH_LBU 0x4003 +#define INSN_MASK_LBU 0x707f +#define INSN_MATCH_LHU 0x5003 +#define INSN_MASK_LHU 0x707f +#define INSN_MATCH_LWU 0x6003 +#define INSN_MASK_LWU 0x707f +#define INSN_MATCH_SB 0x23 +#define INSN_MASK_SB 0x707f +#define INSN_MATCH_SH 0x1023 +#define INSN_MASK_SH 0x707f +#define INSN_MATCH_SW 0x2023 +#define INSN_MASK_SW 0x707f +#define INSN_MATCH_SD 0x3023 +#define INSN_MASK_SD 0x707f + +#define INSN_MATCH_FLW 0x2007 +#define INSN_MASK_FLW 0x707f +#define INSN_MATCH_FLD 0x3007 +#define INSN_MASK_FLD 0x707f +#define INSN_MATCH_FLQ 0x4007 +#define INSN_MASK_FLQ 0x707f +#define INSN_MATCH_FSW 0x2027 +#define INSN_MASK_FSW 0x707f +#define INSN_MATCH_FSD 0x3027 +#define INSN_MASK_FSD 0x707f +#define INSN_MATCH_FSQ 0x4027 +#define INSN_MASK_FSQ 0x707f + +#define INSN_MATCH_C_LD 0x6000 +#define INSN_MASK_C_LD 0xe003 +#define INSN_MATCH_C_SD 0xe000 +#define INSN_MASK_C_SD 0xe003 +#define INSN_MATCH_C_LW 0x4000 +#define INSN_MASK_C_LW 0xe003 +#define INSN_MATCH_C_SW 0xc000 +#define INSN_MASK_C_SW 0xe003 +#define INSN_MATCH_C_LDSP 0x6002 +#define INSN_MASK_C_LDSP 0xe003 +#define INSN_MATCH_C_SDSP 0xe002 +#define INSN_MASK_C_SDSP 0xe003 +#define INSN_MATCH_C_LWSP 0x4002 +#define INSN_MASK_C_LWSP 0xe003 +#define INSN_MATCH_C_SWSP 0xc002 +#define INSN_MASK_C_SWSP 0xe003 + +#define INSN_MATCH_C_FLD 0x2000 +#define INSN_MASK_C_FLD 0xe003 +#define INSN_MATCH_C_FLW 0x6000 +#define INSN_MASK_C_FLW 0xe003 +#define INSN_MATCH_C_FSD 0xa000 +#define INSN_MASK_C_FSD 0xe003 +#define INSN_MATCH_C_FSW 0xe000 +#define INSN_MASK_C_FSW 0xe003 +#define INSN_MATCH_C_FLDSP 0x2002 +#define INSN_MASK_C_FLDSP 0xe003 +#define INSN_MATCH_C_FSDSP 0xa002 +#define INSN_MASK_C_FSDSP 0xe003 +#define INSN_MATCH_C_FLWSP 0x6002 +#define INSN_MASK_C_FLWSP 0xe003 +#define INSN_MATCH_C_FSWSP 0xe002 +#define INSN_MASK_C_FSWSP 0xe003 + +#define INSN_LEN(insn) ((((insn) & 0x3) < 0x3) ? 2 : 4) + +#if defined(CONFIG_64BIT) +#define LOG_REGBYTES 3 +#define XLEN 64 +#else +#define LOG_REGBYTES 2 +#define XLEN 32 +#endif +#define REGBYTES (1 << LOG_REGBYTES) +#define XLEN_MINUS_16 ((XLEN) - 16) + +#define SH_RD 7 +#define SH_RS1 15 +#define SH_RS2 20 +#define SH_RS2C 2 + +#define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1)) +#define RVC_LW_IMM(x) ((RV_X(x, 6, 1) << 2) | \ + (RV_X(x, 10, 3) << 3) | \ + (RV_X(x, 5, 1) << 6)) +#define RVC_LD_IMM(x) ((RV_X(x, 10, 3) << 3) | \ + (RV_X(x, 5, 2) << 6)) +#define RVC_LWSP_IMM(x) ((RV_X(x, 4, 3) << 2) | \ + (RV_X(x, 12, 1) << 5) | \ + (RV_X(x, 2, 2) << 6)) +#define RVC_LDSP_IMM(x) ((RV_X(x, 5, 2) << 3) | \ + (RV_X(x, 12, 1) << 5) | \ + (RV_X(x, 2, 3) << 6)) +#define RVC_SWSP_IMM(x) ((RV_X(x, 9, 4) << 2) | \ + (RV_X(x, 7, 2) << 6)) +#define RVC_SDSP_IMM(x) ((RV_X(x, 10, 3) << 3) | \ + (RV_X(x, 7, 3) << 6)) +#define RVC_RS1S(insn) (8 + RV_X(insn, SH_RD, 3)) +#define RVC_RS2S(insn) (8 + RV_X(insn, SH_RS2C, 3)) +#define RVC_RS2(insn) RV_X(insn, SH_RS2C, 5) + +#define SHIFT_RIGHT(x, y) \ + ((y) < 0 ? ((x) << -(y)) : ((x) >> (y))) + +#define REG_MASK \ + ((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES)) + +#define REG_OFFSET(insn, pos) \ + (SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK) + +#define REG_PTR(insn, pos, regs) \ + (ulong *)((ulong)(regs) + REG_OFFSET(insn, pos)) + +#define GET_RM(insn) (((insn) >> 12) & 7) + +#define GET_RS1(insn, regs) (*REG_PTR(insn, SH_RS1, regs)) +#define GET_RS2(insn, regs) (*REG_PTR(insn, SH_RS2, regs)) +#define GET_RS1S(insn, regs) (*REG_PTR(RVC_RS1S(insn), 0, regs)) +#define GET_RS2S(insn, regs) (*REG_PTR(RVC_RS2S(insn), 0, regs)) +#define GET_RS2C(insn, regs) (*REG_PTR(insn, SH_RS2C, regs)) +#define GET_SP(regs) (*REG_PTR(2, 0, regs)) +#define SET_RD(insn, regs, val) (*REG_PTR(insn, SH_RD, regs) = (val)) +#define IMM_I(insn) ((s32)(insn) >> 20) +#define IMM_S(insn) (((s32)(insn) >> 25 << 5) | \ + (s32)(((insn) >> 7) & 0x1f)) +#define MASK_FUNCT3 0x7000 + +#define GET_PRECISION(insn) (((insn) >> 25) & 3) +#define GET_RM(insn) (((insn) >> 12) & 7) +#define PRECISION_S 0 +#define PRECISION_D 1 + +#define DECLARE_UNPRIVILEGED_LOAD_FUNCTION(type, insn) \ +static inline type load_##type(const type *addr) \ +{ \ + type val; \ + asm (#insn " %0, %1" \ + : "=&r" (val) : "m" (*addr)); \ + return val; \ +} + +#define DECLARE_UNPRIVILEGED_STORE_FUNCTION(type, insn) \ +static inline void store_##type(type *addr, type val) \ +{ \ + asm volatile (#insn " %0, %1\n" \ + : : "r" (val), "m" (*addr)); \ +} + +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u8, lbu) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u16, lhu) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(s8, lb) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(s16, lh) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(s32, lw) +DECLARE_UNPRIVILEGED_STORE_FUNCTION(u8, sb) +DECLARE_UNPRIVILEGED_STORE_FUNCTION(u16, sh) +DECLARE_UNPRIVILEGED_STORE_FUNCTION(u32, sw) +#if defined(CONFIG_64BIT) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u32, lwu) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u64, ld) +DECLARE_UNPRIVILEGED_STORE_FUNCTION(u64, sd) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(ulong, ld) +#else +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(u32, lw) +DECLARE_UNPRIVILEGED_LOAD_FUNCTION(ulong, lw) + +static inline u64 load_u64(const u64 *addr) +{ + return load_u32((u32 *)addr) + + ((u64)load_u32((u32 *)addr + 1) << 32); +} + +static inline void store_u64(u64 *addr, u64 val) +{ + store_u32((u32 *)addr, val); + store_u32((u32 *)addr + 1, val >> 32); +} +#endif + +static inline ulong get_insn(ulong mepc) +{ + register ulong __mepc asm ("a2") = mepc; + ulong val, rvc_mask = 3, tmp; + + asm ("and %[tmp], %[addr], 2\n" + "bnez %[tmp], 1f\n" +#if defined(CONFIG_64BIT) + __stringify(LWU) " %[insn], (%[addr])\n" +#else + __stringify(LW) " %[insn], (%[addr])\n" +#endif + "and %[tmp], %[insn], %[rvc_mask]\n" + "beq %[tmp], %[rvc_mask], 2f\n" + "sll %[insn], %[insn], %[xlen_minus_16]\n" + "srl %[insn], %[insn], %[xlen_minus_16]\n" + "j 2f\n" + "1:\n" + "lhu %[insn], (%[addr])\n" + "and %[tmp], %[insn], %[rvc_mask]\n" + "bne %[tmp], %[rvc_mask], 2f\n" + "lhu %[tmp], 2(%[addr])\n" + "sll %[tmp], %[tmp], 16\n" + "add %[insn], %[insn], %[tmp]\n" + "2:" + : [insn] "=&r" (val), [tmp] "=&r" (tmp) + : [addr] "r" (__mepc), [rvc_mask] "r" (rvc_mask), + [xlen_minus_16] "i" (XLEN_MINUS_16)); + + return val; +} + +union reg_data { + u8 data_bytes[8]; + ulong data_ulong; + u64 data_u64; +}; + +int handle_misaligned_load(struct pt_regs *regs) +{ + union reg_data val; + unsigned long epc = regs->epc; + unsigned long insn = get_insn(epc); + unsigned long addr = csr_read(mtval); + int i, fp = 0, shift = 0, len = 0; + + regs->epc = 0; + + if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) { + len = 4; + shift = 8 * (sizeof(unsigned long) - len); +#if defined(CONFIG_64BIT) + } else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) { + len = 8; + shift = 8 * (sizeof(unsigned long) - len); + } else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) { + len = 4; +#endif + } else if ((insn & INSN_MASK_FLD) == INSN_MATCH_FLD) { + fp = 1; + len = 8; + } else if ((insn & INSN_MASK_FLW) == INSN_MATCH_FLW) { + fp = 1; + len = 4; + } else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) { + len = 2; + shift = 8 * (sizeof(unsigned long) - len); + } else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) { + len = 2; +#if defined(CONFIG_64BIT) + } else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) { + len = 8; + shift = 8 * (sizeof(unsigned long) - len); + insn = RVC_RS2S(insn) << SH_RD; + } else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP && + ((insn >> SH_RD) & 0x1f)) { + len = 8; + shift = 8 * (sizeof(unsigned long) - len); +#endif + } else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) { + len = 4; + shift = 8 * (sizeof(unsigned long) - len); + insn = RVC_RS2S(insn) << SH_RD; + } else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP && + ((insn >> SH_RD) & 0x1f)) { + len = 4; + shift = 8 * (sizeof(unsigned long) - len); + } else if ((insn & INSN_MASK_C_FLD) == INSN_MATCH_C_FLD) { + fp = 1; + len = 8; + insn = RVC_RS2S(insn) << SH_RD; + } else if ((insn & INSN_MASK_C_FLDSP) == INSN_MATCH_C_FLDSP) { + fp = 1; + len = 8; +#if defined(CONFIG_32BIT) + } else if ((insn & INSN_MASK_C_FLW) == INSN_MATCH_C_FLW) { + fp = 1; + len = 4; + insn = RVC_RS2S(insn) << SH_RD; + } else if ((insn & INSN_MASK_C_FLWSP) == INSN_MATCH_C_FLWSP) { + fp = 1; + len = 4; +#endif + } else { + regs->epc = epc; + return -1; + } + + val.data_u64 = 0; + for (i = 0; i < len; i++) + val.data_bytes[i] = load_u8((void *)(addr + i)); + + if (fp) + return -1; + SET_RD(insn, regs, val.data_ulong << shift >> shift); + + regs->epc = epc + INSN_LEN(insn); + + return 0; +} + +int handle_misaligned_store(struct pt_regs *regs) +{ + union reg_data val; + unsigned long epc = regs->epc; + unsigned long insn = get_insn(epc); + unsigned long addr = csr_read(mtval); + int i, len = 0; + + regs->epc = 0; + + val.data_ulong = GET_RS2(insn, regs); + + if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) { + len = 4; +#if defined(CONFIG_64BIT) + } else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) { + len = 8; +#endif + } else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) { + len = 2; +#if defined(CONFIG_64BIT) + } else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) { + len = 8; + val.data_ulong = GET_RS2S(insn, regs); + } else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP) { + len = 8; + val.data_ulong = GET_RS2C(insn, regs); +#endif + } else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) { + len = 4; + val.data_ulong = GET_RS2S(insn, regs); + } else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP) { + len = 4; + val.data_ulong = GET_RS2C(insn, regs); + } else { + regs->epc = epc; + return -1; + } + + for (i = 0; i < len; i++) + store_u8((void *)(addr + i), val.data_bytes[i]); + + regs->epc = epc + INSN_LEN(insn); + + return 0; +} |