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/* SPDX-License-Identifier: GPL-2.0-only */
#include <stddef.h>
#include <stdint.h>
#include <vm.h>
#include <arch/exception.h>
#include <commonlib/helpers.h>
/* these functions are defined in src/arch/riscv/fp_asm.S */
#if defined(__riscv_flen)
#if __riscv_flen >= 32
extern void read_f32(int regnum, uint32_t *v);
extern void write_f32(int regnum, uint32_t *v);
#endif // __riscv_flen >= 32
#if __riscv_flen >= 64
extern void read_f64(int regnum, uint64_t *v);
extern void write_f64(int regnum, uint64_t *v);
#endif // __riscv_flen >= 64
#endif // defined(__riscv_flen)
/* This union makes it easy to read multibyte types by byte operations. */
union endian_buf {
uint8_t b[8];
uint16_t h[4];
uint32_t w[2];
uint64_t d[1];
uintptr_t v;
};
/* This struct hold info of load/store instruction */
struct memory_instruction_info {
/* opcode/mask used to identify instruction,
* (instruction_val) & mask == opcode */
uint32_t opcode;
uint32_t mask;
/* reg_shift/reg_mask/reg_addition used to get register number
* ((instruction_val >> reg_shift) & reg_mask) + reg_addition */
unsigned int reg_shift;
unsigned int reg_mask;
unsigned int reg_addition;
unsigned int is_fp : 1; /* mark as a float operation */
unsigned int is_load : 1; /* mark as a load operation */
unsigned int width : 8; /* Record the memory width of the operation */
unsigned int sign_extend : 1; /* mark need to be sign extended */
};
static struct memory_instruction_info insn_info[] = {
#if __riscv_xlen == 128
{ 0x00002000, 0x0000e003, 2, 7, 8, 0, 1, 16, 1}, // C.LQ
#else
{ 0x00002000, 0x0000e003, 2, 7, 8, 1, 1, 8, 0}, // C.FLD
#endif
{ 0x00004000, 0x0000e003, 2, 7, 8, 0, 1, 4, 1}, // C.LW
#if __riscv_xlen == 32
{ 0x00006000, 0x0000e003, 2, 7, 8, 1, 1, 4, 0}, // C.FLW
#else
{ 0x00006000, 0x0000e003, 2, 7, 8, 0, 1, 8, 1}, // C.LD
#endif
#if __riscv_xlen == 128
{ 0x0000a000, 0x0000e003, 2, 7, 8, 0, 0, 16, 0}, // C.SQ
#else
{ 0x0000a000, 0x0000e003, 2, 7, 8, 1, 0, 8, 0}, // C.FSD
#endif
{ 0x0000c000, 0x0000e003, 2, 7, 8, 0, 0, 4, 0}, // C.SW
#if __riscv_xlen == 32
{ 0x0000e000, 0x0000e003, 2, 7, 8, 1, 0, 4, 0}, // C.FSW
#else
{ 0x0000e000, 0x0000e003, 2, 7, 8, 0, 0, 8, 0}, // C.SD
#endif
#if __riscv_xlen == 128
{ 0x00002002, 0x0000e003, 7, 15, 0, 0, 1, 16, 1}, // C.LQSP
#else
{ 0x00002002, 0x0000e003, 7, 15, 0, 1, 1, 8, 0}, // C.FLDSP
#endif
{ 0x00004002, 0x0000e003, 7, 15, 0, 0, 1, 4, 1}, // C.LWSP
#if __riscv_xlen == 32
{ 0x00006002, 0x0000e003, 7, 15, 0, 1, 1, 4, 0}, // C.FLWSP
#else
{ 0x00006002, 0x0000e003, 7, 15, 0, 0, 1, 8, 1}, // C.LDSP
#endif
#if __riscv_xlen == 128
{ 0x0000a002, 0x0000e003, 2, 15, 0, 0, 0, 16, 0}, // C.SQSP
#else
{ 0x0000a002, 0x0000e003, 2, 15, 0, 1, 0, 8, 0}, // C.FSDSP
#endif
{ 0x0000c002, 0x0000e003, 2, 15, 0, 0, 0, 4, 0}, // C.SWSP
#if __riscv_xlen == 32
{ 0x0000e002, 0x0000e003, 2, 15, 0, 1, 0, 4, 0}, // C.FSWSP
#else
{ 0x0000e002, 0x0000e003, 2, 15, 0, 0, 0, 8, 0}, // C.SDSP
#endif
{ 0x00000003, 0x0000707f, 7, 15, 0, 0, 1, 1, 1}, // LB
{ 0x00001003, 0x0000707f, 7, 15, 0, 0, 1, 2, 1}, // LH
{ 0x00002003, 0x0000707f, 7, 15, 0, 0, 1, 4, 1}, // LW
#if __riscv_xlen > 32
{ 0x00003003, 0x0000707f, 7, 15, 0, 0, 1, 8, 1}, // LD
#endif
{ 0x00004003, 0x0000707f, 7, 15, 0, 0, 1, 1, 0}, // LBU
{ 0x00005003, 0x0000707f, 7, 15, 0, 0, 1, 2, 0}, // LHU
{ 0x00006003, 0x0000707f, 7, 15, 0, 0, 1, 4, 0}, // LWU
{ 0x00000023, 0x0000707f, 20, 15, 0, 0, 0, 1, 0}, // SB
{ 0x00001023, 0x0000707f, 20, 15, 0, 0, 0, 2, 0}, // SH
{ 0x00002023, 0x0000707f, 20, 15, 0, 0, 0, 4, 0}, // SW
#if __riscv_xlen > 32
{ 0x00003023, 0x0000707f, 20, 15, 0, 0, 0, 8, 0}, // SD
#endif
#if defined(__riscv_flen)
#if __riscv_flen >= 32
{ 0x00002007, 0x0000707f, 7, 15, 0, 1, 1, 4, 0}, // FLW
{ 0x00003007, 0x0000707f, 7, 15, 0, 1, 1, 8, 0}, // FLD
#endif // __riscv_flen >= 32
#if __riscv_flen >= 64
{ 0x00002027, 0x0000707f, 20, 15, 0, 1, 0, 4, 0}, // FSW
{ 0x00003027, 0x0000707f, 20, 15, 0, 1, 0, 8, 0}, // FSD
#endif // __riscv_flen >= 64
#endif // defined(__riscv_flen)
};
static struct memory_instruction_info *match_instruction(uintptr_t insn)
{
int i;
for (i = 0; i < ARRAY_SIZE(insn_info); i++)
if ((insn_info[i].mask & insn) == insn_info[i].opcode)
return &(insn_info[i]);
return NULL;
}
static int fetch_16bit_instruction(uintptr_t vaddr, uintptr_t *insn, int *size)
{
uint16_t ins = mprv_read_mxr_u16((uint16_t *)vaddr);
if (EXTRACT_FIELD(ins, 0x3) != 3) {
*insn = ins;
*size = 2;
return 0;
}
return -1;
}
static int fetch_32bit_instruction(uintptr_t vaddr, uintptr_t *insn, int *size)
{
uint32_t l = (uint32_t)mprv_read_mxr_u16((uint16_t *)vaddr + 0);
uint32_t h = (uint32_t)mprv_read_mxr_u16((uint16_t *)vaddr + 1);
uint32_t ins = (h << 16) | l;
if ((EXTRACT_FIELD(ins, 0x3) == 3) &&
(EXTRACT_FIELD(ins, 0x1c) != 0x7)) {
*insn = ins;
*size = 4;
return 0;
}
return -1;
}
void handle_misaligned(trapframe *tf)
{
uintptr_t insn = 0;
union endian_buf buff;
int insn_size = 0;
/* try to fetch 16/32 bits instruction */
if (fetch_16bit_instruction(tf->epc, &insn, &insn_size) < 0) {
if (fetch_32bit_instruction(tf->epc, &insn, &insn_size) < 0) {
redirect_trap();
return;
}
}
/* matching instruction */
struct memory_instruction_info *match = match_instruction(insn);
if (!match) {
redirect_trap();
return;
}
int regnum;
regnum = ((insn >> match->reg_shift) & match->reg_mask);
regnum = regnum + match->reg_addition;
buff.v = 0;
if (match->is_load) {
/* load operation */
/* reading from memory by bytes prevents misaligned
* memory access */
for (int i = 0; i < match->width; i++) {
uint8_t *addr = (uint8_t *)(tf->badvaddr + i);
buff.b[i] = mprv_read_u8(addr);
}
/* sign extend for signed integer loading */
if (match->sign_extend)
if (buff.v >> (8 * match->width - 1))
buff.v |= -1 << (8 * match->width);
/* write to register */
if (match->is_fp) {
int done = 0;
#if defined(__riscv_flen)
#if __riscv_flen >= 32
/* single-precision floating-point */
if (match->width == 4) {
write_f32(regnum, buff.w);
done = 1;
}
#endif // __riscv_flen >= 32
#if __riscv_flen >= 64
/* double-precision floating-point */
if (match->width == 8) {
write_f64(regnum, buff.d);
done = 1;
}
#endif // __riscv_flen >= 64
#endif // defined(__riscv_flen)
if (!done)
redirect_trap();
} else {
tf->gpr[regnum] = buff.v;
}
} else {
/* store operation */
/* reading from register */
if (match->is_fp) {
int done = 0;
#if defined(__riscv_flen)
#if __riscv_flen >= 32
if (match->width == 4) {
read_f32(regnum, buff.w);
done = 1;
}
#endif // __riscv_flen >= 32
#if __riscv_flen >= 64
if (match->width == 8) {
read_f64(regnum, buff.d);
done = 1;
}
#endif // __riscv_flen >= 64
#endif // defined(__riscv_flen)
if (!done)
redirect_trap();
} else {
buff.v = tf->gpr[regnum];
}
/* writing to memory by bytes prevents misaligned
* memory access */
for (int i = 0; i < match->width; i++) {
uint8_t *addr = (uint8_t *)(tf->badvaddr + i);
mprv_write_u8(addr, buff.b[i]);
}
}
/* return to where we came from */
write_csr(mepc, read_csr(mepc) + insn_size);
}
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