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target/riscv: Update [m|h]tinst CSR in riscv_cpu_do_interrupt()
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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.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Acked-by: dramforever <dramforever@live.com>
Message-Id: <20220630061150.905174-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
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@avpatel @alistair23
avpatel authored and alistair23 committed Sep 7, 2022
1 parent 946e9bc commit 8e2aa21
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Showing 3 changed files with 296 additions and 6 deletions.
5 changes: 5 additions & 0 deletions target/riscv/cpu.h
View file
Expand Up @@ -285,6 +285,11 @@ struct CPUArchState {
/* Signals whether the current exception occurred with two-stage address
translation active. */
bool two_stage_lookup;
/*
* Signals whether the current exception occurred while doing two-stage
* address translation for the VS-stage page table walk.
*/
bool two_stage_indirect_lookup;

target_ulong scounteren;
target_ulong mcounteren;
Expand Down
252 changes: 246 additions & 6 deletions target/riscv/cpu_helper.c
View file
Expand Up @@ -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"
Expand Down Expand Up @@ -1053,7 +1054,8 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical,

static void raise_mmu_exception(CPURISCVState *env, target_ulong address,
MMUAccessType access_type, bool pmp_violation,
bool first_stage, bool two_stage)
bool first_stage, bool two_stage,
bool two_stage_indirect)
{
CPUState *cs = env_cpu(env);
int page_fault_exceptions, vm;
Expand Down Expand Up @@ -1103,6 +1105,7 @@ static void raise_mmu_exception(CPURISCVState *env, target_ulong address,
}
env->badaddr = address;
env->two_stage_lookup = two_stage;
env->two_stage_indirect_lookup = two_stage_indirect;
}

hwaddr riscv_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
Expand Down Expand Up @@ -1148,6 +1151,7 @@ void riscv_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
env->badaddr = addr;
env->two_stage_lookup = riscv_cpu_virt_enabled(env) ||
riscv_cpu_two_stage_lookup(mmu_idx);
env->two_stage_indirect_lookup = false;
cpu_loop_exit_restore(cs, retaddr);
}

Expand All @@ -1173,6 +1177,7 @@ void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
env->badaddr = addr;
env->two_stage_lookup = riscv_cpu_virt_enabled(env) ||
riscv_cpu_two_stage_lookup(mmu_idx);
env->two_stage_indirect_lookup = false;
cpu_loop_exit_restore(cs, retaddr);
}

Expand All @@ -1188,6 +1193,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
bool pmp_violation = false;
bool first_stage_error = true;
bool two_stage_lookup = false;
bool two_stage_indirect_error = false;
int ret = TRANSLATE_FAIL;
int mode = mmu_idx;
/* default TLB page size */
Expand Down Expand Up @@ -1225,6 +1231,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
*/
if (ret == TRANSLATE_G_STAGE_FAIL) {
first_stage_error = false;
two_stage_indirect_error = true;
access_type = MMU_DATA_LOAD;
}

Expand Down Expand Up @@ -1308,12 +1315,218 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
raise_mmu_exception(env, address, access_type, pmp_violation,
first_stage_error,
riscv_cpu_virt_enabled(env) ||
riscv_cpu_two_stage_lookup(mmu_idx));
riscv_cpu_two_stage_lookup(mmu_idx),
two_stage_indirect_error);
cpu_loop_exit_restore(cs, retaddr);
}

return true;
}

static target_ulong riscv_transformed_insn(CPURISCVState *env,
target_ulong insn,
target_ulong taddr)
{
target_ulong xinsn = 0;
target_ulong access_rs1 = 0, access_imm = 0, access_size = 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));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_LD_IMM(insn);
access_size = 8;
}
break;
case OPC_RISC_C_FUNC_LW: /* C.LW */
xinsn = OPC_RISC_LW;
xinsn = SET_RD(xinsn, GET_C_RS2S(insn));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_LW_IMM(insn);
access_size = 4;
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));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_LW_IMM(insn);
access_size = 4;
} else { /* C.LD (RV64/RV128) */
xinsn = OPC_RISC_LD;
xinsn = SET_RD(xinsn, GET_C_RS2S(insn));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_LD_IMM(insn);
access_size = 8;
}
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));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_SD_IMM(insn);
access_size = 8;
}
break;
case OPC_RISC_C_FUNC_SW: /* C.SW */
xinsn = OPC_RISC_SW;
xinsn = SET_RS2(xinsn, GET_C_RS2S(insn));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_SW_IMM(insn);
access_size = 4;
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));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_SW_IMM(insn);
access_size = 4;
} else { /* C.SD (RV64/RV128) */
xinsn = OPC_RISC_SD;
xinsn = SET_RS2(xinsn, GET_C_RS2S(insn));
access_rs1 = GET_C_RS1S(insn);
access_imm = GET_C_SD_IMM(insn);
access_size = 8;
}
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));
access_rs1 = 2;
access_imm = GET_C_LDSP_IMM(insn);
access_size = 8;
}
break;
case OPC_RISC_C_FUNC_LWSP: /* C.LWSP */
xinsn = OPC_RISC_LW;
xinsn = SET_RD(xinsn, GET_C_RD(insn));
access_rs1 = 2;
access_imm = GET_C_LWSP_IMM(insn);
access_size = 4;
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));
access_rs1 = 2;
access_imm = GET_C_LWSP_IMM(insn);
access_size = 4;
} else { /* C.LDSP (RV64/RV128) */
xinsn = OPC_RISC_LD;
xinsn = SET_RD(xinsn, GET_C_RD(insn));
access_rs1 = 2;
access_imm = GET_C_LDSP_IMM(insn);
access_size = 8;
}
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));
access_rs1 = 2;
access_imm = GET_C_SDSP_IMM(insn);
access_size = 8;
}
break;
case OPC_RISC_C_FUNC_SWSP: /* C.SWSP */
xinsn = OPC_RISC_SW;
xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
access_rs1 = 2;
access_imm = GET_C_SWSP_IMM(insn);
access_size = 4;
break;
case 7:
if (riscv_cpu_xlen(env) == 32) { /* C.FSWSP (RV32) */
xinsn = OPC_RISC_FSW;
xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
access_rs1 = 2;
access_imm = GET_C_SWSP_IMM(insn);
access_size = 4;
} else { /* C.SDSP (RV64/RV128) */
xinsn = OPC_RISC_SD;
xinsn = SET_RS2(xinsn, GET_C_RS2(insn));
access_rs1 = 2;
access_imm = GET_C_SDSP_IMM(insn);
access_size = 8;
}
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 {
/* Transform 32bit (or wider) instructions */
switch (MASK_OP_MAJOR(insn)) {
case OPC_RISC_ATOMIC:
xinsn = insn;
access_rs1 = GET_RS1(insn);
access_size = 1 << GET_FUNCT3(insn);
break;
case OPC_RISC_LOAD:
case OPC_RISC_FP_LOAD:
xinsn = SET_I_IMM(insn, 0);
access_rs1 = GET_RS1(insn);
access_imm = GET_IMM(insn);
access_size = 1 << GET_FUNCT3(insn);
break;
case OPC_RISC_STORE:
case OPC_RISC_FP_STORE:
xinsn = SET_S_IMM(insn, 0);
access_rs1 = GET_RS1(insn);
access_imm = GET_STORE_IMM(insn);
access_size = 1 << GET_FUNCT3(insn);
break;
case OPC_RISC_SYSTEM:
if (MASK_OP_SYSTEM(insn) == OPC_RISC_HLVHSV) {
xinsn = insn;
access_rs1 = GET_RS1(insn);
access_size = 1 << ((GET_FUNCT7(insn) >> 1) & 0x3);
access_size = 1 << access_size;
}
break;
default:
break;
}
}

if (access_size) {
xinsn = SET_RS1(xinsn, (taddr - (env->gpr[access_rs1] + access_imm)) &
(access_size - 1));
}

return xinsn;
}
#endif /* !CONFIG_USER_ONLY */

/*
Expand All @@ -1338,6 +1551,7 @@ 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;

Expand All @@ -1353,20 +1567,43 @@ 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;
if (env->two_stage_indirect_lookup) {
/*
* special pseudoinstruction for G-stage fault taken while
* doing VS-stage page table walk.
*/
tinst = (riscv_cpu_xlen(env) == 32) ? 0x00002000 : 0x00003000;
} else {
/*
* The "Addr. Offset" field in transformed instruction is
* non-zero only for misaligned access.
*/
tinst = riscv_transformed_insn(env, env->bins, tval);
}
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;
if (env->two_stage_indirect_lookup) {
/*
* special pseudoinstruction for G-stage fault taken while
* doing VS-stage page table walk.
*/
tinst = (riscv_cpu_xlen(env) == 32) ? 0x00002000 : 0x00003000;
}
break;
case RISCV_EXCP_ILLEGAL_INST:
case RISCV_EXCP_VIRT_INSTRUCTION_FAULT:
Expand Down Expand Up @@ -1446,6 +1683,7 @@ 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);
Expand Down Expand Up @@ -1476,6 +1714,7 @@ 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);
Expand All @@ -1488,6 +1727,7 @@ void riscv_cpu_do_interrupt(CPUState *cs)
*/

env->two_stage_lookup = false;
env->two_stage_indirect_lookup = false;
#endif
cs->exception_index = RISCV_EXCP_NONE; /* mark handled to qemu */
}

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