Signed-off-by: Jim Wilson <jimw@sifive.com>
---
 target/riscv/cpu.c     |  9 ++++++-
 target/riscv/gdbstub.c | 73 ++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 73 insertions(+), 9 deletions(-)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index a025a0a..b248e3e 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -305,6 +305,8 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    riscv_cpu_register_gdb_regs_for_features(cs);
+
     qemu_init_vcpu(cs);
     cpu_reset(cs);
 
@@ -345,7 +347,12 @@ static void riscv_cpu_class_init(ObjectClass *c, void *data)
     cc->synchronize_from_tb = riscv_cpu_synchronize_from_tb;
     cc->gdb_read_register = riscv_cpu_gdb_read_register;
     cc->gdb_write_register = riscv_cpu_gdb_write_register;
-    cc->gdb_num_core_regs = 65;
+    cc->gdb_num_core_regs = 33;
+#if defined(TARGET_RISCV32)
+    cc->gdb_core_xml_file = "riscv-32bit-cpu.xml";
+#elif defined(TARGET_RISCV64)
+    cc->gdb_core_xml_file = "riscv-64bit-cpu.xml";
+#endif
     cc->gdb_stop_before_watchpoint = true;
     cc->disas_set_info = riscv_cpu_disas_set_info;
 #ifdef CONFIG_USER_ONLY
diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
index b06f0fa..9558d80 100644
--- a/target/riscv/gdbstub.c
+++ b/target/riscv/gdbstub.c
@@ -31,10 +31,6 @@ int riscv_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
         return gdb_get_regl(mem_buf, env->gpr[n]);
     } else if (n == 32) {
         return gdb_get_regl(mem_buf, env->pc);
-    } else if (n < 65) {
-        return gdb_get_reg64(mem_buf, env->fpr[n - 33]);
-    } else if (n < 4096 + 65) {
-        return gdb_get_regl(mem_buf, csr_read_helper(env, n - 65, true));
     }
     return 0;
 }
@@ -53,11 +49,72 @@ int riscv_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
     } else if (n == 32) {
         env->pc = ldtul_p(mem_buf);
         return sizeof(target_ulong);
-    } else if (n < 65) {
-        env->fpr[n - 33] = ldq_p(mem_buf); /* always 64-bit */
+    }
+    return 0;
+}
+
+static int riscv_gdb_get_fpu(CPURISCVState *env, uint8_t *mem_buf, int n)
+{
+    if (n < 32) {
+        return gdb_get_reg64(mem_buf, env->fpr[n]);
+    } else if (n < 35) {
+        /*
+         * CSR_FFLAGS is 0x001, and gdb says it is FP register 32, so we
+         * subtract 31 to map the gdb FP register number to the CSR number.
+         * This also works for CSR_FRM and CSR_FCSR.
+         */
+        return gdb_get_regl(mem_buf, csr_read_helper(env, n - 31, true));
+    }
+    return 0;
+}
+
+static int riscv_gdb_set_fpu(CPURISCVState *env, uint8_t *mem_buf, int n)
+{
+    if (n < 32) {
+        env->fpr[n] = ldq_p(mem_buf); /* always 64-bit */
         return sizeof(uint64_t);
-    } else if (n < 4096 + 65) {
-        csr_write_helper(env, ldtul_p(mem_buf), n - 65, true);
+    } else if (n < 35) {
+        /*
+         * CSR_FFLAGS is 0x001, and gdb says it is FP register 32, so we
+         * subtract 31 to map the gdb FP register number to the CSR number.
+         * This also works for CSR_FRM and CSR_FCSR.
+         */
+        csr_write_helper(env, ldtul_p(mem_buf), n - 31, true);
     }
     return 0;
 }
+
+static int riscv_gdb_get_csr(CPURISCVState *env, uint8_t *mem_buf, int n)
+{
+    if (n < ARRAY_SIZE(csr_register_map)) {
+        return gdb_get_regl(mem_buf, csr_read_helper(env, csr_register_map[n],
+                                                     true));
+    }
+    return 0;
+}
+
+static int riscv_gdb_set_csr(CPURISCVState *env, uint8_t *mem_buf, int n)
+{
+    if (n < ARRAY_SIZE(csr_register_map)) {
+        csr_write_helper(env, ldtul_p(mem_buf), csr_register_map[n], true);
+    }
+    return 0;
+}
+
+void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
+{
+    /* ??? Assume all targets have FPU regs for now.  */
+#if defined(TARGET_RISCV32)
+    gdb_register_coprocessor(cs, riscv_gdb_get_fpu, riscv_gdb_set_fpu,
+                             35, "riscv-32bit-fpu.xml", 0);
+
+    gdb_register_coprocessor(cs, riscv_gdb_get_csr, riscv_gdb_set_csr,
+                             4096, "riscv-32bit-csr.xml", 0);
+#elif defined(TARGET_RISCV64)
+    gdb_register_coprocessor(cs, riscv_gdb_get_fpu, riscv_gdb_set_fpu,
+                             35, "riscv-64bit-fpu.xml", 0);
+
+    gdb_register_coprocessor(cs, riscv_gdb_get_csr, riscv_gdb_set_csr,
+                             4096, "riscv-64bit-csr.xml", 0);
+#endif
+}
-- 
2.7.4

On Fri, Dec 28, 2018 at 2:20 PM Jim Wilson <jimw@sifive.com> wrote:
>
> Signed-off-by: Jim Wilson <jimw@sifive.com>
> ---
>  target/riscv/cpu.c     |  9 ++++++-
>  target/riscv/gdbstub.c | 73 ++++++++++++++++++++++++++++++++++++++++++++------
>  2 files changed, 73 insertions(+), 9 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index a025a0a..b248e3e 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -305,6 +305,8 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
>          return;
>      }
>
> +    riscv_cpu_register_gdb_regs_for_features(cs);
> +
>      qemu_init_vcpu(cs);
>      cpu_reset(cs);
>
> @@ -345,7 +347,12 @@ static void riscv_cpu_class_init(ObjectClass *c, void *data)
>      cc->synchronize_from_tb = riscv_cpu_synchronize_from_tb;
>      cc->gdb_read_register = riscv_cpu_gdb_read_register;
>      cc->gdb_write_register = riscv_cpu_gdb_write_register;
> -    cc->gdb_num_core_regs = 65;
> +    cc->gdb_num_core_regs = 33;
> +#if defined(TARGET_RISCV32)
> +    cc->gdb_core_xml_file = "riscv-32bit-cpu.xml";
> +#elif defined(TARGET_RISCV64)
> +    cc->gdb_core_xml_file = "riscv-64bit-cpu.xml";
> +#endif
>      cc->gdb_stop_before_watchpoint = true;
>      cc->disas_set_info = riscv_cpu_disas_set_info;
>  #ifdef CONFIG_USER_ONLY
> diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
> index b06f0fa..9558d80 100644
> --- a/target/riscv/gdbstub.c
> +++ b/target/riscv/gdbstub.c
> @@ -31,10 +31,6 @@ int riscv_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
>          return gdb_get_regl(mem_buf, env->gpr[n]);
>      } else if (n == 32) {
>          return gdb_get_regl(mem_buf, env->pc);
> -    } else if (n < 65) {
> -        return gdb_get_reg64(mem_buf, env->fpr[n - 33]);
> -    } else if (n < 4096 + 65) {
> -        return gdb_get_regl(mem_buf, csr_read_helper(env, n - 65, true));
>      }
>      return 0;
>  }
> @@ -53,11 +49,72 @@ int riscv_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
>      } else if (n == 32) {
>          env->pc = ldtul_p(mem_buf);
>          return sizeof(target_ulong);
> -    } else if (n < 65) {
> -        env->fpr[n - 33] = ldq_p(mem_buf); /* always 64-bit */
> +    }
> +    return 0;
> +}
> +
> +static int riscv_gdb_get_fpu(CPURISCVState *env, uint8_t *mem_buf, int n)
> +{
> +    if (n < 32) {
> +        return gdb_get_reg64(mem_buf, env->fpr[n]);
> +    } else if (n < 35) {
> +        /*
> +         * CSR_FFLAGS is 0x001, and gdb says it is FP register 32, so we
> +         * subtract 31 to map the gdb FP register number to the CSR number.
> +         * This also works for CSR_FRM and CSR_FCSR.
> +         */
> +        return gdb_get_regl(mem_buf, csr_read_helper(env, n - 31, true));
> +    }
> +    return 0;
> +}
> +
> +static int riscv_gdb_set_fpu(CPURISCVState *env, uint8_t *mem_buf, int n)
> +{
> +    if (n < 32) {
> +        env->fpr[n] = ldq_p(mem_buf); /* always 64-bit */
>          return sizeof(uint64_t);
> -    } else if (n < 4096 + 65) {
> -        csr_write_helper(env, ldtul_p(mem_buf), n - 65, true);
> +    } else if (n < 35) {
> +        /*
> +         * CSR_FFLAGS is 0x001, and gdb says it is FP register 32, so we
> +         * subtract 31 to map the gdb FP register number to the CSR number.
> +         * This also works for CSR_FRM and CSR_FCSR.
> +         */
> +        csr_write_helper(env, ldtul_p(mem_buf), n - 31, true);
>      }
>      return 0;
>  }
> +
> +static int riscv_gdb_get_csr(CPURISCVState *env, uint8_t *mem_buf, int n)
> +{
> +    if (n < ARRAY_SIZE(csr_register_map)) {
> +        return gdb_get_regl(mem_buf, csr_read_helper(env, csr_register_map[n],
> +                                                     true));
> +    }
> +    return 0;
> +}
> +
> +static int riscv_gdb_set_csr(CPURISCVState *env, uint8_t *mem_buf, int n)
> +{
> +    if (n < ARRAY_SIZE(csr_register_map)) {
> +        csr_write_helper(env, ldtul_p(mem_buf), csr_register_map[n], true);
> +    }
> +    return 0;
> +}
> +
> +void riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
> +{
> +    /* ??? Assume all targets have FPU regs for now.  */

You can get env and then check for floating point support:

CPURISCVState *env = &cs->env;
if (env->misa_mask & RVF) {
...

Alistair

> +#if defined(TARGET_RISCV32)
> +    gdb_register_coprocessor(cs, riscv_gdb_get_fpu, riscv_gdb_set_fpu,
> +                             35, "riscv-32bit-fpu.xml", 0);
> +
> +    gdb_register_coprocessor(cs, riscv_gdb_get_csr, riscv_gdb_set_csr,
> +                             4096, "riscv-32bit-csr.xml", 0);
> +#elif defined(TARGET_RISCV64)
> +    gdb_register_coprocessor(cs, riscv_gdb_get_fpu, riscv_gdb_set_fpu,
> +                             35, "riscv-64bit-fpu.xml", 0);
> +
> +    gdb_register_coprocessor(cs, riscv_gdb_get_csr, riscv_gdb_set_csr,
> +                             4096, "riscv-64bit-csr.xml", 0);
> +#endif
> +}
> --
> 2.7.4
>
>

On Tue, Jan 22, 2019 at 1:52 PM Alistair Francis <alistair23@gmail.com> wrote:
> You can get env and then check for floating point support:
>
> CPURISCVState *env = &cs->env;
> if (env->misa_mask & RVF) {
> ...

I needed this which wasn't hard to figure out.
    RISCVCPU *cpu = RISCV_CPU(cs);
    CPURISCVState *env = &cpu->env;
    if (env->misa & RVF) {

The tricky bit was figuring out how to test it, because I wasn't sure
if making registers conditional would actually work.  I figured out
that using -machine sifive_e gives me a target with no fpu, and
playing with that a bit I get the expected result, which is that the
FP regs don't print anymore.  The FP related CSRs still do, but that
would require gdb fixes I think, because gdb knows that they are both
FP regs and CSR, and tries to print them both ways.  That leads to a
more general problem of figuring out exactly which CSRs a particular
target implements, which is a bigger problem than I have time to fix
at the moment, and should be handled as a separate problem.

Since my patch set is now a month old, I'll rebase onto current master
and post a version 3 patch set.

Jim

On Mon, 28 Jan 2019 19:11:58 PST (-0800), Jim Wilson wrote:
> On Tue, Jan 22, 2019 at 1:52 PM Alistair Francis <alistair23@gmail.com> wrote:
>> You can get env and then check for floating point support:
>>
>> CPURISCVState *env = &cs->env;
>> if (env->misa_mask & RVF) {
>> ...
>
> I needed this which wasn't hard to figure out.
>     RISCVCPU *cpu = RISCV_CPU(cs);
>     CPURISCVState *env = &cpu->env;
>     if (env->misa & RVF) {
>
> The tricky bit was figuring out how to test it, because I wasn't sure
> if making registers conditional would actually work.  I figured out
> that using -machine sifive_e gives me a target with no fpu, and
> playing with that a bit I get the expected result, which is that the
> FP regs don't print anymore.  The FP related CSRs still do, but that
> would require gdb fixes I think, because gdb knows that they are both
> FP regs and CSR, and tries to print them both ways.  That leads to a
> more general problem of figuring out exactly which CSRs a particular
> target implements, which is a bigger problem than I have time to fix
> at the moment, and should be handled as a separate problem.
>
> Since my patch set is now a month old, I'll rebase onto current master
> and post a version 3 patch set.

Thanks!