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/*
* Copyright (c) 2018 Western Digital Corporation or its affiliates.
*
* Authors:
* Anup Patel <anup.patel@wdc.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <sbi/riscv_asm.h>
#include <sbi/riscv_encoding.h>
#include <sbi/sbi_bits.h>
#include <sbi/sbi_emulate_csr.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_illegal_insn.h>
#include <sbi/sbi_trap.h>
#include <sbi/sbi_unpriv.h>
#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
typedef int (*illegal_insn_func)(ulong insn,
u32 hartid, ulong mcause,
struct sbi_trap_regs *regs,
struct sbi_scratch *scratch);
static int truly_illegal_insn(ulong insn,
u32 hartid, ulong mcause,
struct sbi_trap_regs *regs,
struct sbi_scratch *scratch)
{
/* For now, always fails */
return SBI_ENOTSUPP;
}
static int system_opcode_insn(ulong insn,
u32 hartid, ulong mcause,
struct sbi_trap_regs *regs,
struct sbi_scratch *scratch)
{
int do_write, rs1_num = (insn >> 15) & 0x1f;
ulong rs1_val = GET_RS1(insn, regs);
int csr_num = (u32)insn >> 20;
ulong csr_val, new_csr_val;
if (sbi_emulate_csr_read(csr_num, hartid, regs->mstatus,
scratch, &csr_val))
return truly_illegal_insn(insn, hartid, mcause,
regs, scratch);
do_write = rs1_num;
switch (GET_RM(insn)) {
case 1:
new_csr_val = rs1_val;
do_write = 1;
break;
case 2:
new_csr_val = csr_val | rs1_val;
break;
case 3: new_csr_val = csr_val & ~rs1_val;
break;
case 5:
new_csr_val = rs1_num;
do_write = 1;
break;
case 6:
new_csr_val = csr_val | rs1_num;
break;
case 7:
new_csr_val = csr_val & ~rs1_num;
break;
default:
return truly_illegal_insn(insn, hartid, mcause,
regs, scratch);
};
if (do_write &&
sbi_emulate_csr_write(csr_num, hartid, regs->mstatus,
scratch, new_csr_val))
return truly_illegal_insn(insn, hartid, mcause,
regs, scratch);
SET_RD(insn, regs, csr_val);
regs->mepc += 4;
return 0;
}
static illegal_insn_func illegal_insn_table[32] = {
truly_illegal_insn, /* 0 */
truly_illegal_insn, /* 1 */
truly_illegal_insn, /* 2 */
truly_illegal_insn, /* 3 */
truly_illegal_insn, /* 4 */
truly_illegal_insn, /* 5 */
truly_illegal_insn, /* 6 */
truly_illegal_insn, /* 7 */
truly_illegal_insn, /* 8 */
truly_illegal_insn, /* 9 */
truly_illegal_insn, /* 10 */
truly_illegal_insn, /* 11 */
truly_illegal_insn, /* 12 */
truly_illegal_insn, /* 13 */
truly_illegal_insn, /* 14 */
truly_illegal_insn, /* 15 */
truly_illegal_insn, /* 16 */
truly_illegal_insn, /* 17 */
truly_illegal_insn, /* 18 */
truly_illegal_insn, /* 19 */
truly_illegal_insn, /* 20 */
truly_illegal_insn, /* 21 */
truly_illegal_insn, /* 22 */
truly_illegal_insn, /* 23 */
truly_illegal_insn, /* 24 */
truly_illegal_insn, /* 25 */
truly_illegal_insn, /* 26 */
truly_illegal_insn, /* 27 */
system_opcode_insn, /* 28 */
truly_illegal_insn, /* 29 */
truly_illegal_insn, /* 30 */
truly_illegal_insn /* 31 */
};
int sbi_illegal_insn_handler(u32 hartid, ulong mcause,
struct sbi_trap_regs *regs,
struct sbi_scratch *scratch)
{
ulong mstatus;
ulong insn = csr_read(mbadaddr);
if (unlikely((insn & 3) != 3)) {
if (insn == 0) {
mstatus = csr_read(mstatus);
insn = get_insn(regs->mepc, &mstatus);
}
if ((insn & 3) != 3)
return SBI_ENOTSUPP;
}
return illegal_insn_table[(insn & 0x7c) >> 2](insn, hartid, mcause,
regs, scratch);
}
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