Re: [Qemu-devel] [PATCH v2 2/2] target-arm: Add support for AArch32ARMv8 CRC32 instructionss

["Alex Bennée" <alex.bennee@linaro.org>]

will.newton@linaro.org writes:

> Add support for AArch32 CRC32 and CRC32C instructions added in ARMv8.
> The CRC32-C implementation used is the built-in qemu implementation
> and The CRC-32 implementation is from zlib. This requires adding zlib
> to LIBS to ensure it is linked for the linux-user binary.
>
> Signed-off-by: Will Newton <will.newton@linaro.org>
> ---
>  configure              |  2 +-
>  target-arm/helper.c    | 39 +++++++++++++++++++++++++++++++++++++++
>  target-arm/helper.h    |  3 +++
>  target-arm/translate.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 91 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 4648117..822842c 100755
> --- a/configure
> +++ b/configure
> @@ -1550,7 +1550,7 @@ EOF
>              "Make sure to have the zlib libs and headers installed."
>      fi
>  fi
> -libs_softmmu="$libs_softmmu -lz"
> +LIBS="$LIBS -lz"
>  
>  ##########################################
>  # libseccomp check
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 5ae08c9..294cfaf 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -5,6 +5,8 @@
>  #include "sysemu/arch_init.h"
>  #include "sysemu/sysemu.h"
>  #include "qemu/bitops.h"
> +#include "qemu/crc32c.h"
> +#include <zlib.h> /* For crc32 */
>  
>  #ifndef CONFIG_USER_ONLY
>  static inline int get_phys_addr(CPUARMState *env, uint32_t address,
> @@ -4468,3 +4470,40 @@ int arm_rmode_to_sf(int rmode)
>      }
>      return rmode;
>  }
> +
> +static void crc_init_buffer(uint8_t *buf, uint32_t val, uint32_t bytes)
> +{
> +    memset(buf, 0, 4);
> +
> +    if (bytes == 1) {
> +        buf[0] = val & 0xff;
> +    } else if (bytes == 2) {
> +        buf[0] = val & 0xff;
> +        buf[1] = (val >> 8) & 0xff;
> +    } else {
> +        buf[0] = val & 0xff;
> +        buf[1] = (val >> 8) & 0xff;
> +        buf[2] = (val >> 16) & 0xff;
> +        buf[3] = (val >> 24) & 0xff;
> +    }
> +}
> +
> +uint32_t HELPER(crc32)(uint32_t acc, uint32_t val, uint32_t bytes)
> +{
> +    uint8_t buf[4];
> +
> +    crc_init_buffer(buf, val, bytes);
> +
> +    /* zlib crc32 converts the accumulator and output to one's complement.  */
> +    return crc32(acc ^ 0xffffffff, buf, bytes) ^ 0xffffffff;
> +}
> +
> +uint32_t HELPER(crc32c)(uint32_t acc, uint32_t val, uint32_t bytes)
> +{
> +    uint8_t buf[4];
> +
> +    crc_init_buffer(buf, val, bytes);
> +
> +    /* Linux crc32c converts the output to one's complement.  */
> +    return crc32c(acc, buf, bytes) ^ 0xffffffff;
> +}
> diff --git a/target-arm/helper.h b/target-arm/helper.h
> index 951e6ad..fb92e53 100644
> --- a/target-arm/helper.h
> +++ b/target-arm/helper.h
> @@ -494,6 +494,9 @@ DEF_HELPER_3(neon_qzip32, void, env, i32, i32)
>  DEF_HELPER_4(crypto_aese, void, env, i32, i32, i32)
>  DEF_HELPER_4(crypto_aesmc, void, env, i32, i32, i32)
>  
> +DEF_HELPER_3(crc32, i32, i32, i32, i32)
> +DEF_HELPER_3(crc32c, i32, i32, i32, i32)
> +
>  #ifdef TARGET_AARCH64
>  #include "helper-a64.h"
>  #endif
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index 782aab8..9410b6a 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -7541,6 +7541,32 @@ static void disas_arm_insn(CPUARMState * env, DisasContext *s)
>              store_reg(s, 14, tmp2);
>              gen_bx(s, tmp);
>              break;
> +        case 0x4:
> +        {
> +            /* crc32/crc32c */
> +            uint32_t c = extract32(insn, 9, 1);
> +
> +            /* size == 64 is UNPREDICTABLE but handle as UNDEFINED.  */
> +            if (op1 == 0x3) {
> +                goto illegal_op;
> +            }
> +
> +            rn = (insn >> 16) & 0xf;
> +            rd = (insn >> 12) & 0xf;

use extract32?

> +
> +            tmp = load_reg(s, rn);
> +            tmp2 = load_reg(s, rm);
> +            tmp3 = tcg_const_i32(1 << op1);
> +            if (c) {
> +                gen_helper_crc32c(tmp, tmp, tmp2, tmp3);
> +            } else {
> +                gen_helper_crc32(tmp, tmp, tmp2, tmp3);
> +            }
> +            tcg_temp_free_i32(tmp2);
> +            tcg_temp_free_i32(tmp3);
> +            store_reg(s, rd, tmp);
> +            break;
> +        }
>          case 0x5: /* saturating add/subtract */
>              ARCH(5TE);
>              rd = (insn >> 12) & 0xf;
> @@ -9125,6 +9151,28 @@ static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
>                  case 0x18: /* clz */
>                      gen_helper_clz(tmp, tmp);
>                      break;
> +                case 0x20:
> +                case 0x21:
> +                case 0x22:
> +                case 0x28:
> +                case 0x29:
> +                case 0x2a:
> +                {
> +                    /* crc32/crc32c */
> +                    uint32_t sz = op & 0x3;
> +                    uint32_t c = op & 0x8;
> +
> +                    tmp2 = load_reg(s, rm);
> +                    tmp3 = tcg_const_i32(1 << sz);
> +                    if (c) {
> +                        gen_helper_crc32c(tmp, tmp, tmp2, tmp3);
> +                    } else {
> +                        gen_helper_crc32(tmp, tmp, tmp2, tmp3);
> +                    }
> +                    tcg_temp_free_i32(tmp2);
> +                    tcg_temp_free_i32(tmp3);
> +                    break;
> +                }
>                  default:
>                      goto illegal_op;
>                  }

-- 
Alex Bennée