On Tue, May 24, 2022 at 3:08 AM Alistair Francis <alistai...@gmail.com> wrote:
>
> On Thu, May 12, 2022 at 12:47 AM Anup Patel <apa...@ventanamicro.com> wrote:
> >
> > We should write transformed instruction encoding of the trapped
> > instruction in [m|h]tinst CSR at time of taking trap as defined
> > by the RISC-V privileged specification v1.12.
> >
> > Signed-off-by: Anup Patel <apa...@ventanamicro.com>
> > ---
> > target/riscv/cpu_helper.c | 168 +++++++++++++++++++++++++++++++++++++-
> > target/riscv/instmap.h | 41 ++++++++++
> > 2 files changed, 205 insertions(+), 4 deletions(-)
> >
> > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> > index d99fac9d2d..b24652eb8d 100644
> > --- a/target/riscv/cpu_helper.c
> > +++ b/target/riscv/cpu_helper.c
> > @@ -22,6 +22,7 @@
> > #include "qemu/main-loop.h"
> > #include "cpu.h"
> > #include "exec/exec-all.h"
> > +#include "instmap.h"
> > #include "tcg/tcg-op.h"
> > #include "trace.h"
> > #include "semihosting/common-semi.h"
> > @@ -1318,6 +1319,158 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr
> > address, int size,
> > }
> > #endif /* !CONFIG_USER_ONLY */
> >
> > +static target_ulong riscv_transformed_insn(CPURISCVState *env,
> > + target_ulong insn)
> > +{
> > + target_ulong xinsn = 0;
> > +
> > + /*
> > + * Only Quadrant 0 and Quadrant 2 of RVC instruction space need to
> > + * be uncompressed. The Quadrant 1 of RVC instruction space need
> > + * not be transformed because these instructions won't generate
> > + * any load/store trap.
> > + */
> > +
> > + if ((insn & 0x3) != 0x3) {
> > + /* Transform 16bit instruction into 32bit instruction */
> > + switch (GET_C_OP(insn)) {
> > + case OPC_RISC_C_OP_QUAD0: /* Quadrant 0 */
> > + switch (GET_C_FUNC(insn)) {
> > + case OPC_RISC_C_FUNC_FLD_LQ:
> > + if (riscv_cpu_xlen(env) != 128) { /* C.FLD (RV32/64) */
> > + xinsn = OPC_RISC_FLD;
> > + xinsn = SET_RD(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_I_IMM(xinsn, GET_C_LD_IMM(insn));
> > + }
> > + break;
> > + case OPC_RISC_C_FUNC_LW: /* C.LW */
> > + xinsn = OPC_RISC_LW;
> > + xinsn = SET_RD(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_I_IMM(xinsn, GET_C_LW_IMM(insn));
> > + break;
> > + case OPC_RISC_C_FUNC_FLW_LD:
> > + if (riscv_cpu_xlen(env) == 32) { /* C.FLW (RV32) */
> > + xinsn = OPC_RISC_FLW;
> > + xinsn = SET_RD(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_I_IMM(xinsn, GET_C_LW_IMM(insn));
> > + } else { /* C.LD (RV64/RV128) */
> > + xinsn = OPC_RISC_LD;
> > + xinsn = SET_RD(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_I_IMM(xinsn, GET_C_LD_IMM(insn));
> > + }
> > + break;
> > + case OPC_RISC_C_FUNC_FSD_SQ:
> > + if (riscv_cpu_xlen(env) != 128) { /* C.FSD (RV32/64) */
> > + xinsn = OPC_RISC_FSD;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_S_IMM(xinsn, GET_C_SD_IMM(insn));
> > + }
> > + break;
> > + case OPC_RISC_C_FUNC_SW: /* C.SW */
> > + xinsn = OPC_RISC_SW;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_S_IMM(xinsn, GET_C_SW_IMM(insn));
> > + break;
> > + case OPC_RISC_C_FUNC_FSW_SD:
> > + if (riscv_cpu_xlen(env) == 32) { /* C.FSW (RV32) */
> > + xinsn = OPC_RISC_FSW;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_S_IMM(xinsn, GET_C_SW_IMM(insn));
> > + } else { /* C.SD (RV64/RV128) */
> > + xinsn = OPC_RISC_SD;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2S(insn));
> > + xinsn = SET_RS1(xinsn, GET_C_RS1S(insn));
> > + xinsn = SET_S_IMM(xinsn, GET_C_SD_IMM(insn));
> > + }
> > + break;
> > + default:
> > + break;
> > + }
> > + break;
> > + case OPC_RISC_C_OP_QUAD2: /* Quadrant 2 */
> > + switch (GET_C_FUNC(insn)) {
> > + case OPC_RISC_C_FUNC_FLDSP_LQSP:
> > + if (riscv_cpu_xlen(env) != 128) { /* C.FLDSP (RV32/64) */
> > + xinsn = OPC_RISC_FLD;
> > + xinsn = SET_RD(xinsn, GET_C_RD(insn));
> > + xinsn = SET_RS1(xinsn, 2);
>
> Is this right?
>
> Shouldn't this be the offset "between the faulting virtual address
> (written to mtval or stval) and the original virtual address"?
Yes, it should be "Addr. Offset". I totally overlooked the "Addr. Offset"
field.
>
> > + xinsn = SET_I_IMM(xinsn, GET_C_LDSP_IMM(insn));
> > + }
> > + break;
> > + case OPC_RISC_C_FUNC_LWSP: /* C.LWSP */
> > + xinsn = OPC_RISC_LW;
> > + xinsn = SET_RD(xinsn, GET_C_RD(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_I_IMM(xinsn, GET_C_LWSP_IMM(insn));
> > + break;
> > + case OPC_RISC_C_FUNC_FLWSP_LDSP:
> > + if (riscv_cpu_xlen(env) == 32) { /* C.FLWSP (RV32) */
> > + xinsn = OPC_RISC_FLW;
> > + xinsn = SET_RD(xinsn, GET_C_RD(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_I_IMM(xinsn, GET_C_LWSP_IMM(insn));
> > + } else { /* C.LDSP (RV64/RV128) */
> > + xinsn = OPC_RISC_LD;
> > + xinsn = SET_RD(xinsn, GET_C_RD(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_I_IMM(xinsn, GET_C_LDSP_IMM(insn));
> > + }
> > + break;
> > + case OPC_RISC_C_FUNC_FSDSP_SQSP:
> > + if (riscv_cpu_xlen(env) != 128) { /* C.FSDSP (RV32/64) */
> > + xinsn = OPC_RISC_FSD;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_S_IMM(xinsn, GET_C_SDSP_IMM(insn));
> > + }
> > + break;
> > + case OPC_RISC_C_FUNC_SWSP: /* C.SWSP */
> > + xinsn = OPC_RISC_SW;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_S_IMM(xinsn, GET_C_SWSP_IMM(insn));
> > + break;
> > + case 7:
> > + if (riscv_cpu_xlen(env) == 32) { /* C.FSWSP (RV32) */
> > + xinsn = OPC_RISC_FSW;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_S_IMM(xinsn, GET_C_SWSP_IMM(insn));
> > + } else { /* C.SDSP (RV64/RV128) */
> > + xinsn = OPC_RISC_SD;
> > + xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
> > + xinsn = SET_RS1(xinsn, 2);
> > + xinsn = SET_S_IMM(xinsn, GET_C_SDSP_IMM(insn));
> > + }
> > + break;
> > + default:
> > + break;
> > + }
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + /*
> > + * Clear Bit1 of transformed instruction to indicate that
> > + * original insruction was a 16bit instruction
> > + */
> > + xinsn &= ~((target_ulong)0x2);
> > + } else {
> > + /* No need to transform 32bit (or wider) instructions */
>
> From what I can tell we still need to transform 32-bit instructions as
> well, the "Addr. Offset" for example needs to be changed.
The "Addr. Offset" will be non-zero only for misaligned load/store
traps but QEMU RISC-V does not take misaligned load/store traps
so at least for QEMU RISC-V we should always set "Addr. Offset"
to zero.
Regards,
Anup
>
> Alistair
>
> > + xinsn = insn;
> > + }
> > +
> > + return xinsn;
> > +}
> > +
> > /*
> > * Handle Traps
> > *
> > @@ -1340,6 +1493,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> > target_ulong cause = cs->exception_index & RISCV_EXCP_INT_MASK;
> > uint64_t deleg = async ? env->mideleg : env->medeleg;
> > target_ulong tval = 0;
> > + target_ulong tinst = 0;
> > target_ulong htval = 0;
> > target_ulong mtval2 = 0;
> >
> > @@ -1355,18 +1509,22 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> > if (!async) {
> > /* set tval to badaddr for traps with address information */
> > switch (cause) {
> > - case RISCV_EXCP_INST_GUEST_PAGE_FAULT:
> > case RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT:
> > case RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT:
> > - case RISCV_EXCP_INST_ADDR_MIS:
> > - case RISCV_EXCP_INST_ACCESS_FAULT:
> > case RISCV_EXCP_LOAD_ADDR_MIS:
> > case RISCV_EXCP_STORE_AMO_ADDR_MIS:
> > case RISCV_EXCP_LOAD_ACCESS_FAULT:
> > case RISCV_EXCP_STORE_AMO_ACCESS_FAULT:
> > - case RISCV_EXCP_INST_PAGE_FAULT:
> > case RISCV_EXCP_LOAD_PAGE_FAULT:
> > case RISCV_EXCP_STORE_PAGE_FAULT:
> > + write_gva = env->two_stage_lookup;
> > + tval = env->badaddr;
> > + tinst = riscv_transformed_insn(env, env->bins);
> > + break;
> > + case RISCV_EXCP_INST_GUEST_PAGE_FAULT:
> > + case RISCV_EXCP_INST_ADDR_MIS:
> > + case RISCV_EXCP_INST_ACCESS_FAULT:
> > + case RISCV_EXCP_INST_PAGE_FAULT:
> > write_gva = env->two_stage_lookup;
> > tval = env->badaddr;
> > break;
> > @@ -1448,6 +1606,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> > env->sepc = env->pc;
> > env->stval = tval;
> > env->htval = htval;
> > + env->htinst = tinst;
> > env->pc = (env->stvec >> 2 << 2) +
> > ((async && (env->stvec & 3) == 1) ? cause * 4 : 0);
> > riscv_cpu_set_mode(env, PRV_S);
> > @@ -1478,6 +1637,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
> > env->mepc = env->pc;
> > env->mtval = tval;
> > env->mtval2 = mtval2;
> > + env->mtinst = tinst;
> > env->pc = (env->mtvec >> 2 << 2) +
> > ((async && (env->mtvec & 3) == 1) ? cause * 4 : 0);
> > riscv_cpu_set_mode(env, PRV_M);
> > diff --git a/target/riscv/instmap.h b/target/riscv/instmap.h
> > index 40b6d2b64d..f4ee686c78 100644
> > --- a/target/riscv/instmap.h
> > +++ b/target/riscv/instmap.h
> > @@ -316,6 +316,12 @@ enum {
> > #define GET_RS2(inst) extract32(inst, 20, 5)
> > #define GET_RD(inst) extract32(inst, 7, 5)
> > #define GET_IMM(inst) sextract64(inst, 20, 12)
> > +#define SET_RS1(inst, val) deposit32(inst, 15, 5, val)
> > +#define SET_RS2(inst, val) deposit32(inst, 20, 5, val)
> > +#define SET_RD(inst, val) deposit32(inst, 7, 5, val)
> > +#define SET_I_IMM(inst, val) deposit32(inst, 20, 12, val)
> > +#define SET_S_IMM(inst, val) \
> > + deposit32(deposit32(inst, 7, 5, val), 25, 7, (val) >> 5)
> >
> > /* RVC decoding macros */
> > #define GET_C_IMM(inst) (extract32(inst, 2, 5) \
> > @@ -346,6 +352,8 @@ enum {
> > | (extract32(inst, 5, 1) << 6))
> > #define GET_C_LD_IMM(inst) ((extract16(inst, 10, 3) << 3) \
> > | (extract16(inst, 5, 2) << 6))
> > +#define GET_C_SW_IMM(inst) GET_C_LW_IMM(inst)
> > +#define GET_C_SD_IMM(inst) GET_C_LD_IMM(inst)
> > #define GET_C_J_IMM(inst) ((extract32(inst, 3, 3) << 1) \
> > | (extract32(inst, 11, 1) << 4) \
> > | (extract32(inst, 2, 1) << 5) \
> > @@ -366,4 +374,37 @@ enum {
> > #define GET_C_RS1S(inst) (8 + extract16(inst, 7, 3))
> > #define GET_C_RS2S(inst) (8 + extract16(inst, 2, 3))
> >
> > +#define GET_C_FUNC(inst) extract32(inst, 13, 3)
> > +#define GET_C_OP(inst) extract32(inst, 0, 2)
> > +
> > +enum {
> > + /* RVC Quadrants */
> > + OPC_RISC_C_OP_QUAD0 = 0x0,
> > + OPC_RISC_C_OP_QUAD1 = 0x1,
> > + OPC_RISC_C_OP_QUAD2 = 0x2
> > +};
> > +
> > +enum {
> > + /* RVC Quadrant 0 */
> > + OPC_RISC_C_FUNC_ADDI4SPN = 0x0,
> > + OPC_RISC_C_FUNC_FLD_LQ = 0x1,
> > + OPC_RISC_C_FUNC_LW = 0x2,
> > + OPC_RISC_C_FUNC_FLW_LD = 0x3,
> > + OPC_RISC_C_FUNC_FSD_SQ = 0x5,
> > + OPC_RISC_C_FUNC_SW = 0x6,
> > + OPC_RISC_C_FUNC_FSW_SD = 0x7
> > +};
> > +
> > +enum {
> > + /* RVC Quadrant 2 */
> > + OPC_RISC_C_FUNC_SLLI_SLLI64 = 0x0,
> > + OPC_RISC_C_FUNC_FLDSP_LQSP = 0x1,
> > + OPC_RISC_C_FUNC_LWSP = 0x2,
> > + OPC_RISC_C_FUNC_FLWSP_LDSP = 0x3,
> > + OPC_RISC_C_FUNC_JR_MV_EBREAK_JALR_ADD = 0x4,
> > + OPC_RISC_C_FUNC_FSDSP_SQSP = 0x5,
> > + OPC_RISC_C_FUNC_SWSP = 0x6,
> > + OPC_RISC_C_FUNC_FSWSP_SDSP = 0x7
> > +};
> > +
> > #endif
> > --
> > 2.34.1
> >
> >
