Re: [qemu-s390x] [Qemu-devel] [PATCH v1] linux-user: elf: ELF_HWCAP for s390x

[Laurent Vivier]

Le 04/06/2019 à 11:36, David Hildenbrand a écrit :
> Let's add all HWCAPs that we can support under TCG right now, when the
> respective CPU facilities are enabled.
> 
> Cc: Riku Voipio <address@hidden>
> Cc: Laurent Vivier <address@hidden>
> Cc: Cornelia Huck <address@hidden>
> Cc: Laurent Vivier <address@hidden>
> Cc: Richard Henderson <address@hidden>
> Signed-off-by: David Hildenbrand <address@hidden>
> ---
> 
> This patch is based on "[PATCH v2 00/22] s390x/tcg: Vector Instruction
> Support Part 4". I guess it is best if I just include it in my next
> pull request.
Based-on: <address@hidden>
          [PATCH v2 00/22] s390x/tcg: Vector Instruction Support Part 4

> 
> ---
>  include/elf.h        |  1 +
>  linux-user/elfload.c | 39 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/include/elf.h b/include/elf.h
> index ea7708a4ea..3501e0c8d0 100644
> --- a/include/elf.h
> +++ b/include/elf.h
> @@ -598,6 +598,7 @@ typedef struct {
>  #define HWCAP_S390_ETF3EH       256
>  #define HWCAP_S390_HIGH_GPRS    512
>  #define HWCAP_S390_TE           1024
> +#define HWCAP_S390_VXRS         2048
>  
>  /* M68K specific definitions. */
>  /* We use the top 24 bits to encode information about the
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index a57b7049dd..59b813066c 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -1308,6 +1308,45 @@ static inline void init_thread(struct target_pt_regs 
> *regs,
>  #define ELF_DATA     ELFDATA2MSB
>  #define ELF_ARCH     EM_S390
>  
> +#include "elf.h"
> +
> +#define ELF_HWCAP get_elf_hwcap()
> +
> +static uint32_t get_elf_hwcap(void)
> +{
> +    uint32_t hwcap = 0;
> +
> +    if (s390_has_feat(S390_FEAT_ESAN3)) {
> +        hwcap |= HWCAP_S390_ESAN3;
> +    }
> +    if (s390_has_feat(S390_FEAT_ZARCH)) {
> +        hwcap |= HWCAP_S390_ZARCH;
> +    }
> +    if (s390_has_feat(S390_FEAT_STFLE)) {
> +        hwcap |= HWCAP_S390_STFLE;
> +    }
> +    if (s390_has_feat(S390_FEAT_MSA)) {
> +        hwcap |= HWCAP_S390_MSA;
> +    }
> +    if (s390_has_feat(S390_FEAT_LONG_DISPLACEMENT)) {
> +        hwcap |= HWCAP_S390_LDISP;
> +    }
> +    if (s390_has_feat(S390_FEAT_EXTENDED_IMMEDIATE)) {
> +        hwcap |= HWCAP_S390_EIMM;
> +    }
> +    if (s390_has_feat(S390_FEAT_EXTENDED_TRANSLATION_3) &&
> +        s390_has_feat(S390_FEAT_ETF3_ENH)) {
> +        hwcap |= HWCAP_S390_ETF3EH;
> +    }
> +    /* 31-bit processes can use 64-bit registers */
> +    hwcap |= HWCAP_S390_HIGH_GPRS;
> +    if (s390_has_feat(S390_FEAT_VECTOR)) {
> +        hwcap |= HWCAP_S390_VXRS;
> +    }
> +
> +    return hwcap;
> +}
> +
>  static inline void init_thread(struct target_pt_regs *regs, struct 
> image_info *infop)
>  {
>      regs->psw.addr = infop->entry;
> 

Acked-by: Laurent Vivier <address@hidden>

You can also do like the other architectures that use shortcuts like this:

#define GET_FEATURE(feat, hwcap) \
    do { if (s390_has_feat(feat)) { hwcaps |= hwcap; } } while (0)
...
GET_FEATURE(S390_FEAT_VECTOR, HWCAP_S390_VXRS);
...


Thanks,
Laurent