Re: [Qemu-devel] [qemu-s390x] [PATCH v3 08/16] s390-bios: Map low core memory

[Thomas Huth]

On 01/03/2019 19.59, Jason J. Herne wrote:
> Create a new header for basic architecture specific definitions and add a
> mapping of low core memory. This mapping will be used by the real dasd boot
> process.
> 
> Signed-off-by: Jason J. Herne <address@hidden>
> ---
>  pc-bios/s390-ccw/main.c      |   2 +
>  pc-bios/s390-ccw/s390-arch.h | 102 
> +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 104 insertions(+)
>  create mode 100644 pc-bios/s390-ccw/s390-arch.h
> 
> diff --git a/pc-bios/s390-ccw/main.c b/pc-bios/s390-ccw/main.c
> index 2d912cb..0670c14 100644
> --- a/pc-bios/s390-ccw/main.c
> +++ b/pc-bios/s390-ccw/main.c
> @@ -9,6 +9,7 @@
>   */
>  
>  #include "libc.h"
> +#include "s390-arch.h"
>  #include "s390-ccw.h"
>  #include "cio.h"
>  #include "virtio.h"
> @@ -19,6 +20,7 @@ static char loadparm_str[LOADPARM_LEN + 1] = { 0, 0, 0, 0, 
> 0, 0, 0, 0, 0 };
>  QemuIplParameters qipl;
>  IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
>  static bool have_iplb;
> +const LowCore *lowcore; /* Yes, this *is* a pointer to address 0 */

Shouldn't that rather be "LowCore const *lowcore" instead?

>  #define LOADPARM_PROMPT "PROMPT  "
>  #define LOADPARM_EMPTY  "        "
> diff --git a/pc-bios/s390-ccw/s390-arch.h b/pc-bios/s390-ccw/s390-arch.h
> new file mode 100644
> index 0000000..6facce0
> --- /dev/null
> +++ b/pc-bios/s390-ccw/s390-arch.h
> @@ -0,0 +1,102 @@
> +/*
> + * S390 Basic Architecture
> + *
> + * Copyright (c) 2019 Jason J. Herne <address@hidden>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or (at
> + * your option) any later version. See the COPYING file in the top-level
> + * directory.
> + */
> +
> +#ifndef S390_ARCH_H
> +#define S390_ARCH_H
> +
> +typedef struct PSW {
> +    uint64_t mask;
> +    uint64_t addr;
> +} __attribute__ ((aligned(8))) PSW;
> +_Static_assert(sizeof(struct PSW) == 16, "PSW size incorrect");
> +
> +/* Older PSW format used by LPSW instruction */
> +typedef struct PSWLegacy {
> +    uint32_t mask;
> +    uint32_t addr;
> +} __attribute__ ((aligned(8))) PSWLegacy;
> +_Static_assert(sizeof(struct PSWLegacy) == 8, "PSWLegacy size incorrect");
> +
> +/* s390 psw bit masks */
> +#define PSW_MASK_IOINT      0x0200000000000000ULL
> +#define PSW_MASK_WAIT       0x0002000000000000ULL
> +#define PSW_MASK_EAMODE     0x0000000100000000ULL
> +#define PSW_MASK_BAMODE     0x0000000080000000ULL
> +#define PSW_MASK_ZMODE      (PSW_MASK_EAMODE | PSW_MASK_BAMODE)
> +
> +/* Low core mapping */
> +typedef struct LowCore {
> +    /* prefix area: defined by architecture */
> +    PSWLegacy       ipl_psw;                  /* 0x000 */

Maybe remove some white space between the variable type and name
everywhere in this struct?

> +    uint32_t        ccw1[2];                  /* 0x008 */
> +    uint32_t        ccw2[2];                  /* 0x010 */
> +    uint8_t         pad1[0x80 - 0x18];        /* 0x018 */
> +    uint32_t        ext_params;               /* 0x080 */
> +    uint16_t        cpu_addr;                 /* 0x084 */
> +    uint16_t        ext_int_code;             /* 0x086 */
> +    uint16_t        svc_ilen;                 /* 0x088 */
> +    uint16_t        svc_code;                 /* 0x08a */
> +    uint16_t        pgm_ilen;                 /* 0x08c */
> +    uint16_t        pgm_code;                 /* 0x08e */
> +    uint32_t        data_exc_code;            /* 0x090 */
> +    uint16_t        mon_class_num;            /* 0x094 */
> +    uint16_t        per_perc_atmid;           /* 0x096 */
> +    uint64_t        per_address;              /* 0x098 */
> +    uint8_t         exc_access_id;            /* 0x0a0 */
> +    uint8_t         per_access_id;            /* 0x0a1 */
> +    uint8_t         op_access_id;             /* 0x0a2 */
> +    uint8_t         ar_access_id;             /* 0x0a3 */
> +    uint8_t         pad2[0xA8 - 0xA4];        /* 0x0a4 */
> +    uint64_t        trans_exc_code;           /* 0x0a8 */
> +    uint64_t        monitor_code;             /* 0x0b0 */
> +    uint16_t        subchannel_id;            /* 0x0b8 */
> +    uint16_t        subchannel_nr;            /* 0x0ba */
> +    uint32_t        io_int_parm;              /* 0x0bc */
> +    uint32_t        io_int_word;              /* 0x0c0 */
> +    uint8_t         pad3[0xc8 - 0xc4];        /* 0x0c4 */
> +    uint32_t        stfl_fac_list;            /* 0x0c8 */
> +    uint8_t         pad4[0xe8 - 0xcc];        /* 0x0cc */
> +    uint64_t        mcic;                     /* 0x0e8 */
> +    uint8_t         pad5[0xf4 - 0xf0];        /* 0x0f0 */
> +    uint32_t        external_damage_code;     /* 0x0f4 */
> +    uint64_t        failing_storage_address;  /* 0x0f8 */
> +    uint8_t         pad6[0x110 - 0x100];      /* 0x100 */
> +    uint64_t        per_breaking_event_addr;  /* 0x110 */
> +    uint8_t         pad7[0x120 - 0x118];      /* 0x118 */
> +    PSW             restart_old_psw;          /* 0x120 */
> +    PSW             external_old_psw;         /* 0x130 */
> +    PSW             svc_old_psw;              /* 0x140 */
> +    PSW             program_old_psw;          /* 0x150 */
> +    PSW             mcck_old_psw;             /* 0x160 */
> +    PSW             io_old_psw;               /* 0x170 */
> +    uint8_t         pad8[0x1a0 - 0x180];      /* 0x180 */
> +    PSW             restart_new_psw;          /* 0x1a0 */
> +    PSW             external_new_psw;         /* 0x1b0 */
> +    PSW             svc_new_psw;              /* 0x1c0 */
> +    PSW             program_new_psw;          /* 0x1d0 */
> +    PSW             mcck_new_psw;             /* 0x1e0 */
> +    PSW             io_new_psw;               /* 0x1f0 */

So far so good ...

> +    PSW             return_psw;               /* 0x200 */
> +    uint8_t         irb[64];                  /* 0x210 */
> +    uint64_t        sync_enter_timer;         /* 0x250 */
> +    uint64_t        async_enter_timer;        /* 0x258 */
> +    uint64_t        exit_timer;               /* 0x260 */
> +    uint64_t        last_update_timer;        /* 0x268 */
> +    uint64_t        user_timer;               /* 0x270 */
> +    uint64_t        system_timer;             /* 0x278 */
> +    uint64_t        last_update_clock;        /* 0x280 */
> +    uint64_t        steal_clock;              /* 0x288 */
> +    PSW             return_mcck_psw;          /* 0x290 */

... but where do these entries between 0x200 and 0x2a0 come from? They
do not seem to be defined by the Principles of Operation?

> +    uint8_t         pad9[0xc00 - 0x2a0];      /* 0x2a0 */
> +} __attribute__((packed, aligned(8192))) LowCore;
> +
> +extern const LowCore *lowcore;

extern LowCore const *lowcore; ?

> +#endif
> 

 Thomas