On 2023/5/24 13:35, Tommy Wu wrote:
Hi WeiWei Li,
When the CPU is realizing, it will call `riscv_gen_dynamic_csr_xml`
for the first time with the correct `base_reg` value.
code flow :
riscv_cpu_realize
→ riscv_cpu_register_gdb_regs_for_features
→ riscv_gen_dynamic_csr_xml
The functionality of `cpu->dyn_csr_base_reg` is to record the
`base_reg` from
`riscv_cpu_register_gdb_regs_for_features`.
When we try to refresh the dynamic CSRs xml, we will call the function
`riscv_gen_dynamic_csr_xml`
for the second time, and then we can give the correct `base_reg` value
to the function
`riscv_gen_dynamic_csr_xml`, because we've record this value in the
`cpu->dyn_csr_base_reg`.
Oh. Sorry, I stuck.
Reviewed-by: Weiwei Li <liwei...@iscas.ac.cn>
Weiwei Li
Best Regards,
Tommy
On Wed, May 24, 2023 at 10:10 AM Weiwei Li <liwei...@iscas.ac.cn> wrote:
On 2023/5/24 09:59, Tommy Wu wrote:
> Hi Weiwei Li,
>
> `dyn_csr_base_reg` will be used in `riscv_refresh_dynamic_csr_xml`
> We can initialize this variable when the cpu is realized.
I didn't find this initialization in following code.
> And used this variable in `riscv_refresh_dynamic_csr_xml`.
That's my question. In riscv_refresh_dynamic_csr_xml() ,
cpu->dyn_csr_base_reg is passed to riscv_gen_dynamic_csr_xml() as
base_reg.
And then base_reg is assigned to cpu->dyn_csr_base_reg again in
it. So
it's unchanged in this progress.
Another question is dyn_csr_base_reg seems have no additional
function
currently.
Regards,
Weiwei Li
>
> Best regards,
> Tommy
>
>
> On Tue, May 23, 2023 at 10:38 PM Weiwei Li
<liwei...@iscas.ac.cn> wrote:
>
>
> On 2023/5/23 19:44, Tommy Wu wrote:
> > When we change the cpu extension state after the cpu is
> > realized, we cannot print the value of some CSRs in the remote
> > gdb debugger. The root cause is that the dynamic CSR xml is
> > generated when the cpu is realized.
> >
> > This patch add a function to refresh the dynamic CSR xml after
> > the cpu is realized.
> >
> > Signed-off-by: Tommy Wu <tommy...@sifive.com>
> > Reviewed-by: Frank Chang <frank.ch...@sifive.com>
> > ---
> > target/riscv/cpu.h | 2 ++
> > target/riscv/gdbstub.c | 12 ++++++++++++
> > 2 files changed, 14 insertions(+)
> >
> > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> > index de7e43126a..dc8e592275 100644
> > --- a/target/riscv/cpu.h
> > +++ b/target/riscv/cpu.h
> > @@ -494,6 +494,7 @@ struct ArchCPU {
> > CPUNegativeOffsetState neg;
> > CPURISCVState env;
> >
> > + int dyn_csr_base_reg;
>
> dyn_csr_base_reg seems have no additional effect on the
function.
>
> And It remains unmodified in following
> riscv_refresh_dynamic_csr_xml().
>
> Regards,
>
> Weiwei Li
>
> > char *dyn_csr_xml;
> > char *dyn_vreg_xml;
> >
> > @@ -781,6 +782,7 @@ void riscv_get_csr_ops(int csrno,
> riscv_csr_operations *ops);
> > void riscv_set_csr_ops(int csrno, riscv_csr_operations
*ops);
> >
> > void riscv_cpu_register_gdb_regs_for_features(CPUState *cs);
> > +void riscv_refresh_dynamic_csr_xml(CPUState *cs);
> >
> > uint8_t satp_mode_max_from_map(uint32_t map);
> > const char *satp_mode_str(uint8_t satp_mode, bool
is_32_bit);
> > diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
> > index 524bede865..9e97ee2c35 100644
> > --- a/target/riscv/gdbstub.c
> > +++ b/target/riscv/gdbstub.c
> > @@ -230,6 +230,8 @@ static int
> riscv_gen_dynamic_csr_xml(CPUState *cs, int base_reg)
> > bitsize = 64;
> > }
> >
> > + cpu->dyn_csr_base_reg = base_reg;
> > +
> > g_string_printf(s, "<?xml version=\"1.0\"?>");
> > g_string_append_printf(s, "<!DOCTYPE feature SYSTEM
> \"gdb-target.dtd\">");
> > g_string_append_printf(s, "<feature
> name=\"org.gnu.gdb.riscv.csr\">");
> > @@ -349,3 +351,13 @@ void
> riscv_cpu_register_gdb_regs_for_features(CPUState *cs)
> > "riscv-csr.xml", 0);
> > }
> > }
> > +
> > +void riscv_refresh_dynamic_csr_xml(CPUState *cs)
> > +{
> > + RISCVCPU *cpu = RISCV_CPU(cs);
> > + if (!cpu->dyn_csr_xml) {
> > + g_assert_not_reached();
> > + }
> > + g_free(cpu->dyn_csr_xml);
> > + riscv_gen_dynamic_csr_xml(cs, cpu->dyn_csr_base_reg);
> > +}
>
