Message ID | 20211013205104.1031679-6-richard.henderson@linaro.org |
---|---|
State | New |
Headers | show |
Series | target/riscv: Rationalize XLEN and operand length | expand |
On 2021/10/14 上午4:50, Richard Henderson wrote: > Begin adding support for switching XLEN at runtime. Extract the > effective XLEN from MISA and MSTATUS and store for use during translation. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > v2: Force SXL and UXL to valid values. > --- > target/riscv/cpu.h | 2 ++ > target/riscv/cpu.c | 8 ++++++++ > target/riscv/cpu_helper.c | 33 +++++++++++++++++++++++++++++++++ > target/riscv/csr.c | 3 +++ > target/riscv/translate.c | 2 +- > 5 files changed, 47 insertions(+), 1 deletion(-) > > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h > index 87248b562a..445ba5b395 100644 > --- a/target/riscv/cpu.h > +++ b/target/riscv/cpu.h > @@ -395,6 +395,8 @@ FIELD(TB_FLAGS, VILL, 8, 1) > /* Is a Hypervisor instruction load/store allowed? */ > FIELD(TB_FLAGS, HLSX, 9, 1) > FIELD(TB_FLAGS, MSTATUS_HS_FS, 10, 2) > +/* The combination of MXL/SXL/UXL that applies to the current cpu mode. */ > +FIELD(TB_FLAGS, XL, 12, 2) > > #ifdef CONFIG_RISCV32 > #define riscv_cpu_mxl(env) MXL_RV32 > diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c > index 1857670a69..840edd66f8 100644 > --- a/target/riscv/cpu.c > +++ b/target/riscv/cpu.c > @@ -355,6 +355,14 @@ static void riscv_cpu_reset(DeviceState *dev) > env->misa_mxl = env->misa_mxl_max; > env->priv = PRV_M; > env->mstatus &= ~(MSTATUS_MIE | MSTATUS_MPRV); > + if (env->misa_mxl > MXL_RV32) { > + /* > + * The reset status of SXL/UXL is officially undefined, > + * but invalid settings would result in a tcg assert. > + */ > + env->mstatus = set_field(env->mstatus, MSTATUS64_SXL, env->misa_mxl); > + env->mstatus = set_field(env->mstatus, MSTATUS64_UXL, env->misa_mxl); > + } Can you give more explanation about the assert? As the cpu will always reset to M mode, I think we can omit the the setting of UXL or SXL. Thanks, Zhiwei > env->mcause = 0; > env->pc = env->resetvec; > env->two_stage_lookup = false; > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c > index 403f54171d..429afd1f48 100644 > --- a/target/riscv/cpu_helper.c > +++ b/target/riscv/cpu_helper.c > @@ -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; > } > > diff --git a/target/riscv/csr.c b/target/riscv/csr.c > index 9c0753bc8b..c4a479ddd2 100644 > --- a/target/riscv/csr.c > +++ b/target/riscv/csr.c > @@ -526,6 +526,9 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno, > mstatus = set_field(mstatus, MSTATUS32_SD, dirty); > } else { > mstatus = set_field(mstatus, MSTATUS64_SD, dirty); > + /* SXL and UXL fields are for now read only */ > + mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64); > + mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64); > } > env->mstatus = mstatus; > > diff --git a/target/riscv/translate.c b/target/riscv/translate.c > index 422f8ab8d0..7e7bb67d15 100644 > --- a/target/riscv/translate.c > +++ b/target/riscv/translate.c > @@ -539,7 +539,6 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) > #else > ctx->virt_enabled = false; > #endif > - ctx->xl = env->misa_mxl; > ctx->misa_ext = env->misa_ext; > ctx->frm = -1; /* unknown rounding mode */ > ctx->ext_ifencei = cpu->cfg.ext_ifencei; > @@ -551,6 +550,7 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) > ctx->lmul = FIELD_EX32(tb_flags, TB_FLAGS, LMUL); > ctx->mlen = 1 << (ctx->sew + 3 - ctx->lmul); > ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX); > + ctx->xl = FIELD_EX32(tb_flags, TB_FLAGS, XL); > ctx->cs = cs; > ctx->w = false; > ctx->ntemp = 0;
On 10/14/21 1:20 AM, LIU Zhiwei wrote: > > On 2021/10/14 上午4:50, Richard Henderson wrote: >> Begin adding support for switching XLEN at runtime. Extract the >> effective XLEN from MISA and MSTATUS and store for use during translation. >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> --- >> v2: Force SXL and UXL to valid values. >> --- >> target/riscv/cpu.h | 2 ++ >> target/riscv/cpu.c | 8 ++++++++ >> target/riscv/cpu_helper.c | 33 +++++++++++++++++++++++++++++++++ >> target/riscv/csr.c | 3 +++ >> target/riscv/translate.c | 2 +- >> 5 files changed, 47 insertions(+), 1 deletion(-) >> >> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h >> index 87248b562a..445ba5b395 100644 >> --- a/target/riscv/cpu.h >> +++ b/target/riscv/cpu.h >> @@ -395,6 +395,8 @@ FIELD(TB_FLAGS, VILL, 8, 1) >> /* Is a Hypervisor instruction load/store allowed? */ >> FIELD(TB_FLAGS, HLSX, 9, 1) >> FIELD(TB_FLAGS, MSTATUS_HS_FS, 10, 2) >> +/* The combination of MXL/SXL/UXL that applies to the current cpu mode. */ >> +FIELD(TB_FLAGS, XL, 12, 2) >> #ifdef CONFIG_RISCV32 >> #define riscv_cpu_mxl(env) MXL_RV32 >> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c >> index 1857670a69..840edd66f8 100644 >> --- a/target/riscv/cpu.c >> +++ b/target/riscv/cpu.c >> @@ -355,6 +355,14 @@ static void riscv_cpu_reset(DeviceState *dev) >> env->misa_mxl = env->misa_mxl_max; >> env->priv = PRV_M; >> env->mstatus &= ~(MSTATUS_MIE | MSTATUS_MPRV); >> + if (env->misa_mxl > MXL_RV32) { >> + /* >> + * The reset status of SXL/UXL is officially undefined, >> + * but invalid settings would result in a tcg assert. >> + */ >> + env->mstatus = set_field(env->mstatus, MSTATUS64_SXL, env->misa_mxl); >> + env->mstatus = set_field(env->mstatus, MSTATUS64_UXL, env->misa_mxl); >> + } > > Can you give more explanation about the assert? As the cpu will always reset to M mode, I > think we can omit the the setting of UXL or SXL. The mstatus csr is WARL, which means that we should always be able to read a valid value. On init, these fields will still be 0, which isn't right. I guess the assert that I was considering can't really happen, because we'd need to write to mstatus to exit M-mode, and write_mstatus will force these fields to the correct value (as found by Frederic). r~
On Thu, Oct 14, 2021 at 6:56 AM Richard Henderson <richard.henderson@linaro.org> wrote: > > Begin adding support for switching XLEN at runtime. Extract the > effective XLEN from MISA and MSTATUS and store for use during translation. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Alistair > --- > v2: Force SXL and UXL to valid values. > --- > target/riscv/cpu.h | 2 ++ > target/riscv/cpu.c | 8 ++++++++ > target/riscv/cpu_helper.c | 33 +++++++++++++++++++++++++++++++++ > target/riscv/csr.c | 3 +++ > target/riscv/translate.c | 2 +- > 5 files changed, 47 insertions(+), 1 deletion(-) > > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h > index 87248b562a..445ba5b395 100644 > --- a/target/riscv/cpu.h > +++ b/target/riscv/cpu.h > @@ -395,6 +395,8 @@ FIELD(TB_FLAGS, VILL, 8, 1) > /* Is a Hypervisor instruction load/store allowed? */ > FIELD(TB_FLAGS, HLSX, 9, 1) > FIELD(TB_FLAGS, MSTATUS_HS_FS, 10, 2) > +/* The combination of MXL/SXL/UXL that applies to the current cpu mode. */ > +FIELD(TB_FLAGS, XL, 12, 2) > > #ifdef CONFIG_RISCV32 > #define riscv_cpu_mxl(env) MXL_RV32 > diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c > index 1857670a69..840edd66f8 100644 > --- a/target/riscv/cpu.c > +++ b/target/riscv/cpu.c > @@ -355,6 +355,14 @@ static void riscv_cpu_reset(DeviceState *dev) > env->misa_mxl = env->misa_mxl_max; > env->priv = PRV_M; > env->mstatus &= ~(MSTATUS_MIE | MSTATUS_MPRV); > + if (env->misa_mxl > MXL_RV32) { > + /* > + * The reset status of SXL/UXL is officially undefined, > + * but invalid settings would result in a tcg assert. > + */ > + env->mstatus = set_field(env->mstatus, MSTATUS64_SXL, env->misa_mxl); > + env->mstatus = set_field(env->mstatus, MSTATUS64_UXL, env->misa_mxl); > + } > env->mcause = 0; > env->pc = env->resetvec; > env->two_stage_lookup = false; > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c > index 403f54171d..429afd1f48 100644 > --- a/target/riscv/cpu_helper.c > +++ b/target/riscv/cpu_helper.c > @@ -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; > } > > diff --git a/target/riscv/csr.c b/target/riscv/csr.c > index 9c0753bc8b..c4a479ddd2 100644 > --- a/target/riscv/csr.c > +++ b/target/riscv/csr.c > @@ -526,6 +526,9 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno, > mstatus = set_field(mstatus, MSTATUS32_SD, dirty); > } else { > mstatus = set_field(mstatus, MSTATUS64_SD, dirty); > + /* SXL and UXL fields are for now read only */ > + mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64); > + mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64); > } > env->mstatus = mstatus; > > diff --git a/target/riscv/translate.c b/target/riscv/translate.c > index 422f8ab8d0..7e7bb67d15 100644 > --- a/target/riscv/translate.c > +++ b/target/riscv/translate.c > @@ -539,7 +539,6 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) > #else > ctx->virt_enabled = false; > #endif > - ctx->xl = env->misa_mxl; > ctx->misa_ext = env->misa_ext; > ctx->frm = -1; /* unknown rounding mode */ > ctx->ext_ifencei = cpu->cfg.ext_ifencei; > @@ -551,6 +550,7 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) > ctx->lmul = FIELD_EX32(tb_flags, TB_FLAGS, LMUL); > ctx->mlen = 1 << (ctx->sew + 3 - ctx->lmul); > ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX); > + ctx->xl = FIELD_EX32(tb_flags, TB_FLAGS, XL); > ctx->cs = cs; > ctx->w = false; > ctx->ntemp = 0; > -- > 2.25.1 > >
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 87248b562a..445ba5b395 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -395,6 +395,8 @@ FIELD(TB_FLAGS, VILL, 8, 1) /* Is a Hypervisor instruction load/store allowed? */ FIELD(TB_FLAGS, HLSX, 9, 1) FIELD(TB_FLAGS, MSTATUS_HS_FS, 10, 2) +/* The combination of MXL/SXL/UXL that applies to the current cpu mode. */ +FIELD(TB_FLAGS, XL, 12, 2) #ifdef CONFIG_RISCV32 #define riscv_cpu_mxl(env) MXL_RV32 diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 1857670a69..840edd66f8 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -355,6 +355,14 @@ static void riscv_cpu_reset(DeviceState *dev) env->misa_mxl = env->misa_mxl_max; env->priv = PRV_M; env->mstatus &= ~(MSTATUS_MIE | MSTATUS_MPRV); + if (env->misa_mxl > MXL_RV32) { + /* + * The reset status of SXL/UXL is officially undefined, + * but invalid settings would result in a tcg assert. + */ + env->mstatus = set_field(env->mstatus, MSTATUS64_SXL, env->misa_mxl); + env->mstatus = set_field(env->mstatus, MSTATUS64_UXL, env->misa_mxl); + } env->mcause = 0; env->pc = env->resetvec; env->two_stage_lookup = false; diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 403f54171d..429afd1f48 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -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; } diff --git a/target/riscv/csr.c b/target/riscv/csr.c index 9c0753bc8b..c4a479ddd2 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -526,6 +526,9 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno, mstatus = set_field(mstatus, MSTATUS32_SD, dirty); } else { mstatus = set_field(mstatus, MSTATUS64_SD, dirty); + /* SXL and UXL fields are for now read only */ + mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64); + mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64); } env->mstatus = mstatus; diff --git a/target/riscv/translate.c b/target/riscv/translate.c index 422f8ab8d0..7e7bb67d15 100644 --- a/target/riscv/translate.c +++ b/target/riscv/translate.c @@ -539,7 +539,6 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) #else ctx->virt_enabled = false; #endif - ctx->xl = env->misa_mxl; ctx->misa_ext = env->misa_ext; ctx->frm = -1; /* unknown rounding mode */ ctx->ext_ifencei = cpu->cfg.ext_ifencei; @@ -551,6 +550,7 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) ctx->lmul = FIELD_EX32(tb_flags, TB_FLAGS, LMUL); ctx->mlen = 1 << (ctx->sew + 3 - ctx->lmul); ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX); + ctx->xl = FIELD_EX32(tb_flags, TB_FLAGS, XL); ctx->cs = cs; ctx->w = false; ctx->ntemp = 0;
Begin adding support for switching XLEN at runtime. Extract the effective XLEN from MISA and MSTATUS and store for use during translation. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- v2: Force SXL and UXL to valid values. --- target/riscv/cpu.h | 2 ++ target/riscv/cpu.c | 8 ++++++++ target/riscv/cpu_helper.c | 33 +++++++++++++++++++++++++++++++++ target/riscv/csr.c | 3 +++ target/riscv/translate.c | 2 +- 5 files changed, 47 insertions(+), 1 deletion(-)