target/riscv: Add MXL/SXL/UXL to TB_FLAGS

Begin adding support for switching XLEN at runtime.  Extract the
effective XLEN from MISA and MSTATUS and store for use during translation.

Reviewed-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20211020031709.359469-6-richard.henderson@linaro.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Richard Henderson 2021-10-19 20:16:59 -07:00 committed by Alistair Francis
parent db23e5d981
commit 92371bd903
5 changed files with 47 additions and 1 deletions

View file

@ -35,6 +35,37 @@ int riscv_cpu_mmu_index(CPURISCVState *env, bool ifetch)
#endif
}
static RISCVMXL cpu_get_xl(CPURISCVState *env)
{
#if defined(TARGET_RISCV32)
return MXL_RV32;
#elif defined(CONFIG_USER_ONLY)
return MXL_RV64;
#else
RISCVMXL xl = riscv_cpu_mxl(env);
/*
* When emulating a 32-bit-only cpu, use RV32.
* When emulating a 64-bit cpu, and MXL has been reduced to RV32,
* MSTATUSH doesn't have UXL/SXL, therefore XLEN cannot be widened
* back to RV64 for lower privs.
*/
if (xl != MXL_RV32) {
switch (env->priv) {
case PRV_M:
break;
case PRV_U:
xl = get_field(env->mstatus, MSTATUS64_UXL);
break;
default: /* PRV_S | PRV_H */
xl = get_field(env->mstatus, MSTATUS64_SXL);
break;
}
}
return xl;
#endif
}
void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
target_ulong *cs_base, uint32_t *pflags)
{
@ -78,6 +109,8 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
}
#endif
flags = FIELD_DP32(flags, TB_FLAGS, XL, cpu_get_xl(env));
*pflags = flags;
}