| Message ID | b9cb270c4356301ca15d6fec3f651da64beb57d3.1560821342.git.alistair.francis@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Update the RISC-V specification versions | expand |
On Mon, 17 Jun 2019 18:31:08 PDT (-0700), Alistair Francis wrote: > Add a comment for the new mcountinhibit which conflicts with the > CSR_MUCOUNTEREN from version 1.09.1. This can be updated when we remove > 1.09.1. > > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > --- > target/riscv/cpu_bits.h | 1 + > target/riscv/csr.c | 6 ++++-- > 2 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h > index 47450a3cdb..11f971ad5d 100644 > --- a/target/riscv/cpu_bits.h > +++ b/target/riscv/cpu_bits.h > @@ -136,6 +136,7 @@ > #define CSR_MCOUNTEREN 0x306 > > /* Legacy Counter Setup (priv v1.9.1) */ > +/* Update to #define CSR_MCOUNTINHIBIT 0x320 for 1.11.0 */ > #define CSR_MUCOUNTEREN 0x320 > #define CSR_MSCOUNTEREN 0x321 > #define CSR_MHCOUNTEREN 0x322 > diff --git a/target/riscv/csr.c b/target/riscv/csr.c > index c67d29e206..437387fd28 100644 > --- a/target/riscv/csr.c > +++ b/target/riscv/csr.c > @@ -461,18 +461,20 @@ static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val) > return 0; > } > > +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ > static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val) > { > - if (env->priv_ver > PRIV_VERSION_1_09_1) { > + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { > return -1; > } > *val = env->mcounteren; > return 0; > } > > +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ > static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val) > { > - if (env->priv_ver > PRIV_VERSION_1_09_1) { > + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { > return -1; > } > env->mcounteren = val; I don't think this one is right: this should be unsupported on 1.11, as the semantics of this bit are slightly different. It shouldn't be that hard to just emulate it fully for both 1.09.1 and 1.11: for 1.09 this disables access to the counters (which still tick), while for 1.11 it disables ticking the counters (which can still be accessed). Since we don't do anything with the counters in QEMU, I think this should do it LMK if you're OK with me replacing the patch with this commit e9169ccd5ca97a036de41dad23f37f6724712b90 Author: Alistair Francis <alistair.francis@wdc.com> Date: Mon Jun 17 18:31:08 2019 -0700 target/riscv: Add the mcountinhibit CSR 1.11 defines mcountinhibit, which has the same numeric CSR value as mucounteren from 1.09.1 but has different semantics. This patch enables the CSR for 1.11-based targets, which is trivial to implement because the counters in QEMU never tick (legal according to the spec). Signed-off-by: Alistair Francis <alistair.francis@wdc.com> [Palmer: Fix counter access semantics, change commit message to indicate the behavior is fully emulated.] Reviewed-by: Palmer Dabbelt <palmer@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h index 47450a3cdb75..11f971ad5df0 100644 --- a/target/riscv/cpu_bits.h +++ b/target/riscv/cpu_bits.h @@ -136,6 +136,7 @@ #define CSR_MCOUNTEREN 0x306 /* Legacy Counter Setup (priv v1.9.1) */ +/* Update to #define CSR_MCOUNTINHIBIT 0x320 for 1.11.0 */ #define CSR_MUCOUNTEREN 0x320 #define CSR_MSCOUNTEREN 0x321 #define CSR_MHCOUNTEREN 0x322 diff --git a/target/riscv/csr.c b/target/riscv/csr.c index c67d29e20618..2622b2e05474 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -56,6 +56,14 @@ static int fs(CPURISCVState *env, int csrno) static int ctr(CPURISCVState *env, int csrno) { #if !defined(CONFIG_USER_ONLY) + /* + * The counters are always enabled on newer priv specs, as the CSR has + * changed from controlling that the counters can be read to controlling + * that the counters increment. + */ + if (env->priv_ver > PRIV_VERSION_1_09_1) + return 0; + uint32_t ctr_en = ~0u; if (env->priv < PRV_M) { @@ -461,18 +469,20 @@ static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val) return 0; } +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val) { - if (env->priv_ver > PRIV_VERSION_1_09_1) { + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { return -1; } *val = env->mcounteren; return 0; } +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val) { - if (env->priv_ver > PRIV_VERSION_1_09_1) { + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { return -1; } env->mcounteren = val;
On Mon, Jun 24, 2019 at 2:31 AM Palmer Dabbelt <palmer@sifive.com> wrote: > > On Mon, 17 Jun 2019 18:31:08 PDT (-0700), Alistair Francis wrote: > > Add a comment for the new mcountinhibit which conflicts with the > > CSR_MUCOUNTEREN from version 1.09.1. This can be updated when we remove > > 1.09.1. > > > > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > > --- > > target/riscv/cpu_bits.h | 1 + > > target/riscv/csr.c | 6 ++++-- > > 2 files changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h > > index 47450a3cdb..11f971ad5d 100644 > > --- a/target/riscv/cpu_bits.h > > +++ b/target/riscv/cpu_bits.h > > @@ -136,6 +136,7 @@ > > #define CSR_MCOUNTEREN 0x306 > > > > /* Legacy Counter Setup (priv v1.9.1) */ > > +/* Update to #define CSR_MCOUNTINHIBIT 0x320 for 1.11.0 */ > > #define CSR_MUCOUNTEREN 0x320 > > #define CSR_MSCOUNTEREN 0x321 > > #define CSR_MHCOUNTEREN 0x322 > > diff --git a/target/riscv/csr.c b/target/riscv/csr.c > > index c67d29e206..437387fd28 100644 > > --- a/target/riscv/csr.c > > +++ b/target/riscv/csr.c > > @@ -461,18 +461,20 @@ static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val) > > return 0; > > } > > > > +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ > > static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val) > > { > > - if (env->priv_ver > PRIV_VERSION_1_09_1) { > > + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { > > return -1; > > } > > *val = env->mcounteren; > > return 0; > > } > > > > +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ > > static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val) > > { > > - if (env->priv_ver > PRIV_VERSION_1_09_1) { > > + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { > > return -1; > > } > > env->mcounteren = val; > > I don't think this one is right: this should be unsupported on 1.11, as the > semantics of this bit are slightly different. It shouldn't be that hard to > just emulate it fully for both 1.09.1 and 1.11: for 1.09 this disables access > to the counters (which still tick), while for 1.11 it disables ticking the > counters (which can still be accessed). Since we don't do anything with the > counters in QEMU, I think this should do it > > LMK if you're OK with me replacing the patch with this > > commit e9169ccd5ca97a036de41dad23f37f6724712b90 > Author: Alistair Francis <alistair.francis@wdc.com> > Date: Mon Jun 17 18:31:08 2019 -0700 > > target/riscv: Add the mcountinhibit CSR > > 1.11 defines mcountinhibit, which has the same numeric CSR value as > mucounteren from 1.09.1 but has different semantics. This patch enables > the CSR for 1.11-based targets, which is trivial to implement because > the counters in QEMU never tick (legal according to the spec). > > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > [Palmer: Fix counter access semantics, change commit message to indicate > the behavior is fully emulated.] > Reviewed-by: Palmer Dabbelt <palmer@sifive.com> > Signed-off-by: Palmer Dabbelt <palmer@sifive.com> Yep, looks good. Alistair > > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h > index 47450a3cdb75..11f971ad5df0 100644 > --- a/target/riscv/cpu_bits.h > +++ b/target/riscv/cpu_bits.h > @@ -136,6 +136,7 @@ > #define CSR_MCOUNTEREN 0x306 > > /* Legacy Counter Setup (priv v1.9.1) */ > +/* Update to #define CSR_MCOUNTINHIBIT 0x320 for 1.11.0 */ > #define CSR_MUCOUNTEREN 0x320 > #define CSR_MSCOUNTEREN 0x321 > #define CSR_MHCOUNTEREN 0x322 > diff --git a/target/riscv/csr.c b/target/riscv/csr.c > index c67d29e20618..2622b2e05474 100644 > --- a/target/riscv/csr.c > +++ b/target/riscv/csr.c > @@ -56,6 +56,14 @@ static int fs(CPURISCVState *env, int csrno) > static int ctr(CPURISCVState *env, int csrno) > { > #if !defined(CONFIG_USER_ONLY) > + /* > + * The counters are always enabled on newer priv specs, as the CSR has > + * changed from controlling that the counters can be read to controlling > + * that the counters increment. > + */ > + if (env->priv_ver > PRIV_VERSION_1_09_1) > + return 0; > + > uint32_t ctr_en = ~0u; > > if (env->priv < PRV_M) { > @@ -461,18 +469,20 @@ static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val) > return 0; > } > > +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ > static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val) > { > - if (env->priv_ver > PRIV_VERSION_1_09_1) { > + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { > return -1; > } > *val = env->mcounteren; > return 0; > } > > +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ > static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val) > { > - if (env->priv_ver > PRIV_VERSION_1_09_1) { > + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { > return -1; > } > env->mcounteren = val;
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h index 47450a3cdb..11f971ad5d 100644 --- a/target/riscv/cpu_bits.h +++ b/target/riscv/cpu_bits.h @@ -136,6 +136,7 @@ #define CSR_MCOUNTEREN 0x306 /* Legacy Counter Setup (priv v1.9.1) */ +/* Update to #define CSR_MCOUNTINHIBIT 0x320 for 1.11.0 */ #define CSR_MUCOUNTEREN 0x320 #define CSR_MSCOUNTEREN 0x321 #define CSR_MHCOUNTEREN 0x322 diff --git a/target/riscv/csr.c b/target/riscv/csr.c index c67d29e206..437387fd28 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -461,18 +461,20 @@ static int write_mcounteren(CPURISCVState *env, int csrno, target_ulong val) return 0; } +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ static int read_mscounteren(CPURISCVState *env, int csrno, target_ulong *val) { - if (env->priv_ver > PRIV_VERSION_1_09_1) { + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { return -1; } *val = env->mcounteren; return 0; } +/* This regiser is replaced with CSR_MCOUNTINHIBIT in 1.11.0 */ static int write_mscounteren(CPURISCVState *env, int csrno, target_ulong val) { - if (env->priv_ver > PRIV_VERSION_1_09_1) { + if (env->priv_ver > PRIV_VERSION_1_09_1 && env->priv_ver < PRIV_VERSION_1_11_0) { return -1; } env->mcounteren = val;
Add a comment for the new mcountinhibit which conflicts with the CSR_MUCOUNTEREN from version 1.09.1. This can be updated when we remove 1.09.1. Signed-off-by: Alistair Francis <alistair.francis@wdc.com> --- target/riscv/cpu_bits.h | 1 + target/riscv/csr.c | 6 ++++-- 2 files changed, 5 insertions(+), 2 deletions(-)