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// See LICENSE for license details.
#include "emulation.h"
#include "fp_emulation.h"
#include "config.h"
#include "unprivileged_memory.h"
#include "mtrap.h"
#include <limits.h>
static DECLARE_EMULATION_FUNC(emulate_rvc)
{
#ifdef __riscv_compressed
// the only emulable RVC instructions are FP loads and stores.
# if !defined(__riscv_flen) && defined(PK_ENABLE_FP_EMULATION)
write_csr(mepc, mepc + 2);
// if FPU is disabled, punt back to the OS
if (unlikely((mstatus & MSTATUS_FS) == 0))
return truly_illegal_insn(regs, mcause, mepc, mstatus, insn);
if ((insn & MASK_C_FLD) == MATCH_C_FLD) {
uintptr_t addr = GET_RS1S(insn, regs) + RVC_LD_IMM(insn);
if (unlikely(addr % sizeof(uintptr_t)))
return misaligned_load_trap(regs, mcause, mepc);
SET_F64_RD(RVC_RS2S(insn) << SH_RD, regs, load_uint64_t((void *)addr, mepc));
} else if ((insn & MASK_C_FLDSP) == MATCH_C_FLDSP) {
uintptr_t addr = GET_SP(regs) + RVC_LDSP_IMM(insn);
if (unlikely(addr % sizeof(uintptr_t)))
return misaligned_load_trap(regs, mcause, mepc);
SET_F64_RD(insn, regs, load_uint64_t((void *)addr, mepc));
} else if ((insn & MASK_C_FSD) == MATCH_C_FSD) {
uintptr_t addr = GET_RS1S(insn, regs) + RVC_LD_IMM(insn);
if (unlikely(addr % sizeof(uintptr_t)))
return misaligned_store_trap(regs, mcause, mepc);
store_uint64_t((void *)addr, GET_F64_RS2(RVC_RS2S(insn) << SH_RS2, regs), mepc);
} else if ((insn & MASK_C_FSDSP) == MATCH_C_FSDSP) {
uintptr_t addr = GET_SP(regs) + RVC_SDSP_IMM(insn);
if (unlikely(addr % sizeof(uintptr_t)))
return misaligned_store_trap(regs, mcause, mepc);
store_uint64_t((void *)addr, GET_F64_RS2(RVC_RS2(insn) << SH_RS2, regs), mepc);
} else
# if __riscv_xlen == 32
if ((insn & MASK_C_FLW) == MATCH_C_FLW) {
uintptr_t addr = GET_RS1S(insn, regs) + RVC_LW_IMM(insn);
if (unlikely(addr % 4))
return misaligned_load_trap(regs, mcause, mepc);
SET_F32_RD(RVC_RS2S(insn) << SH_RD, regs, load_int32_t((void *)addr, mepc));
} else if ((insn & MASK_C_FLWSP) == MATCH_C_FLWSP) {
uintptr_t addr = GET_SP(regs) + RVC_LWSP_IMM(insn);
if (unlikely(addr % 4))
return misaligned_load_trap(regs, mcause, mepc);
SET_F32_RD(insn, regs, load_int32_t((void *)addr, mepc));
} else if ((insn & MASK_C_FSW) == MATCH_C_FSW) {
uintptr_t addr = GET_RS1S(insn, regs) + RVC_LW_IMM(insn);
if (unlikely(addr % 4))
return misaligned_store_trap(regs, mcause, mepc);
store_uint32_t((void *)addr, GET_F32_RS2(RVC_RS2S(insn) << SH_RS2, regs), mepc);
} else if ((insn & MASK_C_FSWSP) == MATCH_C_FSWSP) {
uintptr_t addr = GET_SP(regs) + RVC_SWSP_IMM(insn);
if (unlikely(addr % 4))
return misaligned_store_trap(regs, mcause, mepc);
store_uint32_t((void *)addr, GET_F32_RS2(RVC_RS2(insn) << SH_RS2, regs), mepc);
} else
# endif
# endif
#endif
return truly_illegal_insn(regs, mcause, mepc, mstatus, insn);
}
void illegal_insn_trap(uintptr_t* regs, uintptr_t mcause, uintptr_t mepc)
{
asm (".pushsection .rodata\n"
"illegal_insn_trap_table:\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#if !defined(__riscv_flen) && defined(PK_ENABLE_FP_EMULATION)
" .word emulate_float_load - illegal_insn_trap_table\n"
#else
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#endif
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#if !defined(__riscv_flen) && defined(PK_ENABLE_FP_EMULATION)
" .word emulate_float_store - illegal_insn_trap_table\n"
#else
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#endif
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#if !defined(__riscv_muldiv)
" .word emulate_mul_div - illegal_insn_trap_table\n"
#else
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#endif
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#if !defined(__riscv_muldiv) && __riscv_xlen >= 64
" .word emulate_mul_div32 - illegal_insn_trap_table\n"
#else
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#endif
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#ifdef PK_ENABLE_FP_EMULATION
" .word emulate_fmadd - illegal_insn_trap_table\n"
" .word emulate_fmadd - illegal_insn_trap_table\n"
" .word emulate_fmadd - illegal_insn_trap_table\n"
" .word emulate_fmadd - illegal_insn_trap_table\n"
" .word emulate_fp - illegal_insn_trap_table\n"
#else
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
#endif
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word emulate_system_opcode - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .word truly_illegal_insn - illegal_insn_trap_table\n"
" .popsection");
uintptr_t mstatus = read_csr(mstatus);
insn_t insn = read_csr(mtval);
if (unlikely((insn & 3) != 3)) {
if (insn == 0)
insn = get_insn(mepc, &mstatus);
if ((insn & 3) != 3)
return emulate_rvc(regs, mcause, mepc, mstatus, insn);
}
write_csr(mepc, mepc + 4);
extern uint32_t illegal_insn_trap_table[];
int32_t* pf = (void*)illegal_insn_trap_table + (insn & 0x7c);
emulation_func f = (emulation_func)((void*)illegal_insn_trap_table + *pf);
f(regs, mcause, mepc, mstatus, insn);
}
__attribute__((noinline))
DECLARE_EMULATION_FUNC(truly_illegal_insn)
{
return redirect_trap(mepc, mstatus, insn);
}
static inline int emulate_read_csr(int num, uintptr_t mstatus, uintptr_t* result)
{
uintptr_t counteren = -1;
if (EXTRACT_FIELD(mstatus, MSTATUS_MPP) == PRV_U)
counteren = read_csr(scounteren);
switch (num)
{
case CSR_TIME:
if (!((counteren >> (CSR_TIME - CSR_CYCLE)) & 1))
return -1;
*result = *mtime;
return 0;
#if __riscv_xlen == 32
case CSR_TIMEH:
if (!((counteren >> (CSR_TIME - CSR_CYCLE)) & 1))
return -1;
*result = *mtime >> 32;
return 0;
#endif
#if !defined(__riscv_flen) && defined(PK_ENABLE_FP_EMULATION)
case CSR_FRM:
if ((mstatus & MSTATUS_FS) == 0) break;
*result = GET_FRM();
return 0;
case CSR_FFLAGS:
if ((mstatus & MSTATUS_FS) == 0) break;
*result = GET_FFLAGS();
return 0;
case CSR_FCSR:
if ((mstatus & MSTATUS_FS) == 0) break;
*result = GET_FCSR();
return 0;
#endif
}
return -1;
}
static inline int emulate_write_csr(int num, uintptr_t value, uintptr_t mstatus)
{
switch (num)
{
#if !defined(__riscv_flen) && defined(PK_ENABLE_FP_EMULATION)
case CSR_FRM: SET_FRM(value); return 0;
case CSR_FFLAGS: SET_FFLAGS(value); return 0;
case CSR_FCSR: SET_FCSR(value); return 0;
#endif
}
return -1;
}
DECLARE_EMULATION_FUNC(emulate_system_opcode)
{
int rs1_num = (insn >> 15) & 0x1f;
uintptr_t rs1_val = GET_RS1(insn, regs);
int csr_num = (uint32_t)insn >> 20;
uintptr_t csr_val, new_csr_val;
if (emulate_read_csr(csr_num, mstatus, &csr_val))
return truly_illegal_insn(regs, mcause, mepc, mstatus, insn);
int do_write = rs1_num;
switch (GET_RM(insn))
{
case 0: return truly_illegal_insn(regs, mcause, mepc, mstatus, 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 4: return truly_illegal_insn(regs, mcause, mepc, mstatus, insn);
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;
}
if (do_write && emulate_write_csr(csr_num, new_csr_val, mstatus))
return truly_illegal_insn(regs, mcause, mepc, mstatus, insn);
SET_RD(insn, regs, csr_val);
}
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