Re: [PATCH 13/15] arm/cpu: Add infra to handle generated ID register definitions

[Eric Auger <eric.auger@redhat.com>]

Hi Connie,


On 2/7/25 12:02 PM, Cornelia Huck wrote:
> From: Eric Auger <eric.auger@redhat.com>
>
> The known ID regs are described in a new initialization function
> dubbed initialize_cpu_sysreg_properties(). That code will be
> automatically generated from linux arch/arm64/tools/sysreg. For the
> time being let's just describe a single id reg, CTR_EL0. In this
> description we only care about non RES/RAZ fields, ie. named fields.
>
> The registers are populated in an array indexed by ARMIDRegisterIdx
> and their fields are added in a sorted list.

I don't think we need all the infra related to properties in this
prerequisite series. I would postpone it until the main CPU model series.

You can just keep scripts/gen-cpu-sysregs-header.awk to generate the
sysreg definitions
>
> [CH: adapted to reworked register storage]
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
>  target/arm/cpu-custom.h            | 55 ++++++++++++++++++++++++++++++
>  target/arm/cpu-sysreg-properties.c | 41 ++++++++++++++++++++++
>  target/arm/cpu64.c                 |  2 ++
>  target/arm/meson.build             |  1 +
>  4 files changed, 99 insertions(+)
>  create mode 100644 target/arm/cpu-custom.h
>  create mode 100644 target/arm/cpu-sysreg-properties.c
>
> diff --git a/target/arm/cpu-custom.h b/target/arm/cpu-custom.h
by the custom we may get rid of the 'custom' terminology
> new file mode 100644
> index 000000000000..17533765dacd
> --- /dev/null
> +++ b/target/arm/cpu-custom.h
> @@ -0,0 +1,55 @@
> +#ifndef ARM_CPU_CUSTOM_H
> +#define ARM_CPU_CUSTOM_H
> +
> +#include "qemu/osdep.h"
> +#include "qemu/error-report.h"
> +#include "cpu.h"
> +#include "cpu-sysregs.h"
> +
> +typedef struct ARM64SysRegField {
> +    const char *name; /* name of the field, for instance CTR_EL0_IDC */
> +    int index;
> +    int lower;
> +    int upper;
> +} ARM64SysRegField;
> +
> +typedef struct ARM64SysReg {
> +    const char *name;   /* name of the sysreg, for instance CTR_EL0 */
> +    ARMSysRegs sysreg;
> +    int index;
> +    GList *fields; /* list of named fields, excluding RES* */
> +} ARM64SysReg;
> +
> +void initialize_cpu_sysreg_properties(void);
> +
> +/*
> + * List of exposed ID regs (automatically populated from linux
> + * arch/arm64/tools/sysreg)
> + */
> +extern ARM64SysReg arm64_id_regs[NUM_ID_IDX];
> +
> +/* Allocate a new field and insert it at the head of the @reg list */
> +static inline GList *arm64_sysreg_add_field(ARM64SysReg *reg, const char *name,
> +                                     uint8_t min, uint8_t max) {
> +
> +     ARM64SysRegField *field = g_new0(ARM64SysRegField, 1);
> +
> +     field->name = name;
> +     field->lower = min;
> +     field->upper = max;
> +     field->index = reg->index;
> +
> +     reg->fields = g_list_append(reg->fields, field);
> +     return reg->fields;
> +}
> +
> +static inline ARM64SysReg *arm64_sysreg_get(ARMIDRegisterIdx index)
> +{
> +        ARM64SysReg *reg = &arm64_id_regs[index];
> +
> +        reg->index = index;
> +        reg->sysreg = id_register_sysreg[index];
> +        return reg;
> +}
> +
> +#endif
> diff --git a/target/arm/cpu-sysreg-properties.c b/target/arm/cpu-sysreg-properties.c
> new file mode 100644
> index 000000000000..8b7ef5badfb9
> --- /dev/null
> +++ b/target/arm/cpu-sysreg-properties.c
> @@ -0,0 +1,41 @@
> +/*
> + * QEMU ARM CPU SYSREG PROPERTIES
> + * to be generated from linux sysreg
> + *
> + * Copyright (c) Red Hat, Inc. 2024
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, see
> + * <http://www.gnu.org/licenses/gpl-2.0.html>
> + */
> +
> +#include "cpu-custom.h"
> +
> +ARM64SysReg arm64_id_regs[NUM_ID_IDX];
> +
> +void initialize_cpu_sysreg_properties(void)
> +{
> +    memset(arm64_id_regs, 0, sizeof(ARM64SysReg) * NUM_ID_IDX);
> +    /* CTR_EL0 */
> +    ARM64SysReg *CTR_EL0 = arm64_sysreg_get(CTR_EL0_IDX);
> +    CTR_EL0->name = "CTR_EL0";
> +    arm64_sysreg_add_field(CTR_EL0, "TminLine", 32, 37);
> +    arm64_sysreg_add_field(CTR_EL0, "DIC", 29, 29);
> +    arm64_sysreg_add_field(CTR_EL0, "IDC", 28, 28);
> +    arm64_sysreg_add_field(CTR_EL0, "CWG", 24, 27);
> +    arm64_sysreg_add_field(CTR_EL0, "ERG", 20, 23);
> +    arm64_sysreg_add_field(CTR_EL0, "DminLine", 16, 19);
> +    arm64_sysreg_add_field(CTR_EL0, "L1Ip", 14, 15);
> +    arm64_sysreg_add_field(CTR_EL0, "IminLine", 0, 3);
> +}
> +
> diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> index beba1733c99f..8371aabce5f4 100644
> --- a/target/arm/cpu64.c
> +++ b/target/arm/cpu64.c
> @@ -35,6 +35,7 @@
>  #include "internals.h"
>  #include "cpu-features.h"
>  #include "cpregs.h"
> +#include "cpu-custom.h"
>  
>  void arm_cpu_sve_finalize(ARMCPU *cpu, Error **errp)
>  {
> @@ -894,6 +895,7 @@ static void aarch64_cpu_register_types(void)
>  {
>      size_t i;
>  
> +    initialize_cpu_sysreg_properties();
>      type_register_static(&aarch64_cpu_type_info);
>  
>      for (i = 0; i < ARRAY_SIZE(aarch64_cpus); ++i) {
> diff --git a/target/arm/meson.build b/target/arm/meson.build
> index 2e10464dbb6b..9c7a04ee1b26 100644
> --- a/target/arm/meson.build
> +++ b/target/arm/meson.build
> @@ -14,6 +14,7 @@ arm_ss.add(when: 'CONFIG_HVF', if_true: files('hyp_gdbstub.c'))
>  arm_ss.add(when: 'TARGET_AARCH64', if_true: files(
>    'cpu64.c',
>    'gdbstub64.c',
> +  'cpu-sysreg-properties.c',
>  ))
>  
>  arm_system_ss = ss.source_set()
Thanks

Eric