Re: [PATCH 01/11 v2] target/riscv: Add CLIC CSR mintstatus

[Alistair Francis <alistair23@gmail.com>]

On Fri, Sep 6, 2024 at 12:44 PM Alistair Francis <alistair23@gmail.com> wrote:
>
> On Tue, Aug 20, 2024 at 2:11 AM Ian Brockbank <Ian.Brockbank@cirrus.com> wrote:
> >
> > From: Ian Brockbank <ian.brockbank@cirrus.com>
> >
> > CSR mintstatus holds the active interrupt level for each supported
> > privilege mode. sintstatus, and user, uintstatus, provide restricted
> > views of mintstatus.
> >
> > Signed-off-by: Ian Brockbank <ian.brockbank@cirrus.com>
> > Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Whoops! Scratch that

>
> > ---
> >  target/riscv/cpu.h      |  3 +++
> >  target/riscv/cpu_bits.h | 11 +++++++++++
> >  target/riscv/csr.c      | 31 +++++++++++++++++++++++++++++++
> >  3 files changed, 45 insertions(+)
> >
> > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> > index 1619c3acb6..95303f50d3 100644
> > --- a/target/riscv/cpu.h
> > +++ b/target/riscv/cpu.h
> > @@ -259,6 +259,7 @@ struct CPUArchState {
> >      bool software_seip;
> >
> >      uint64_t miclaim;
> > +    uint64_t mintstatus; /* clic-spec */
> >
> >      uint64_t mie;
> >      uint64_t mideleg;
> > @@ -461,6 +462,8 @@ struct CPUArchState {
> >      QEMUTimer *vstimer; /* Internal timer for VS-mode interrupt */
> >      bool vstime_irq;
> >
> > +    void *clic;       /* clic interrupt controller */
> > +
> >      hwaddr kernel_addr;
> >      hwaddr fdt_addr;
> >
> > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> > index 32b068f18a..2e65495b54 100644
> > --- a/target/riscv/cpu_bits.h
> > +++ b/target/riscv/cpu_bits.h
> > @@ -165,6 +165,7 @@
> >  #define CSR_MCAUSE          0x342
> >  #define CSR_MTVAL           0x343
> >  #define CSR_MIP             0x344
> > +#define CSR_MINTSTATUS      0xfb1 /* clic-spec-draft */
> >
> >  /* Machine-Level Window to Indirectly Accessed Registers (AIA) */
> >  #define CSR_MISELECT        0x350
> > @@ -206,6 +207,7 @@
> >  #define CSR_SCAUSE          0x142
> >  #define CSR_STVAL           0x143
> >  #define CSR_SIP             0x144
> > +#define CSR_SINTSTATUS      0xdb1 /* clic-spec-draft */
> >
> >  /* Sstc supervisor CSRs */
> >  #define CSR_STIMECMP        0x14D
> > @@ -733,6 +735,15 @@ typedef enum RISCVException {
> >  #define SIP_SEIP                           MIP_SEIP
> >  #define SIP_LCOFIP                         MIP_LCOFIP
> >
> > +/* mintstatus */
> > +#define MINTSTATUS_MIL                     0xff000000 /* mil[31:24] */
> > +#define MINTSTATUS_SIL                     0x0000ff00 /* sil[15:8] */
> > +#define MINTSTATUS_UIL                     0x000000ff /* uil[7:0] */
> > +
> > +/* sintstatus */
> > +#define SINTSTATUS_SIL                     0x0000ff00 /* sil[15:8] */
> > +#define SINTSTATUS_UIL                     0x000000ff /* uil[7:0] */
> > +
> >  /* MIE masks */
> >  #define MIE_SEIE                           (1 << IRQ_S_EXT)
> >  #define MIE_UEIE                           (1 << IRQ_U_EXT)
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index ea3560342c..f9ed7b9079 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -578,6 +578,16 @@ static RISCVException debug(CPURISCVState *env, int csrno)
> >
> >      return RISCV_EXCP_ILLEGAL_INST;
> >  }
> > +
> > +static int clic(CPURISCVState *env, int csrno)
> > +{
> > +    if (env->clic) {

This isn't enough. There are smclic (M-mode) and ssclic (S-mode)
extensions that need to be checked against here to access the CSRs.

At the end of the series they can then be exposed as CPU properties
(which the virt machine can enable when required)

Alistair