// 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 <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 STR(x) XSTR(x)
#define XSTR(x) #x
#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)
STR(LWU) " %[insn], (%[addr])\n"
#else
STR(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 &&
((insn >> SH_RD) & 0x1f)) {
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 &&
((insn >> SH_RD) & 0x1f)) {
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;
}
