target/ppc: Add support for scv and rfscv instructions

POWER9 adds scv and rfscv instructions and the system call vectored
interrupt. Linux does not support this instruction yet but it has
been tested with a modified kernel that runs on real hardware.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
This was tested with out-of-tree Linux patches and seems to work fine.

This fixes the linux-user compile error that David reported last time,
by disabling everything for CONFIG_USER_ONLY. I have the user
implementation which is pretty simple, but we don't have an official
user ABI yet so I'll wait until we get support merged in the kernel.

Thanks,
Nick

 linux-user/ppc/cpu_loop.c       |  1 +
 target/ppc/cpu.h                |  7 ++-
 target/ppc/excp_helper.c        | 98 ++++++++++++++++++++++++---------
 target/ppc/helper.h             |  1 +
 target/ppc/translate.c          | 52 ++++++++++++++++-
 target/ppc/translate_init.inc.c |  3 +-
 6 files changed, 132 insertions(+), 30 deletions(-)

On Thu, May 07, 2020 at 09:53:28PM +1000, Nicholas Piggin wrote:
> POWER9 adds scv and rfscv instructions and the system call vectored
> interrupt. Linux does not support this instruction yet but it has
> been tested with a modified kernel that runs on real hardware.
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Applied to ppc-for-5.1.

> ---
> This was tested with out-of-tree Linux patches and seems to work fine.
> 
> This fixes the linux-user compile error that David reported last time,
> by disabling everything for CONFIG_USER_ONLY. I have the user
> implementation which is pretty simple, but we don't have an official
> user ABI yet so I'll wait until we get support merged in the kernel.
> 
> Thanks,
> Nick
> 
>  linux-user/ppc/cpu_loop.c       |  1 +
>  target/ppc/cpu.h                |  7 ++-
>  target/ppc/excp_helper.c        | 98 ++++++++++++++++++++++++---------
>  target/ppc/helper.h             |  1 +
>  target/ppc/translate.c          | 52 ++++++++++++++++-
>  target/ppc/translate_init.inc.c |  3 +-
>  6 files changed, 132 insertions(+), 30 deletions(-)
> 
> diff --git a/linux-user/ppc/cpu_loop.c b/linux-user/ppc/cpu_loop.c
> index 5b27f8603e..df71e15a25 100644
> --- a/linux-user/ppc/cpu_loop.c
> +++ b/linux-user/ppc/cpu_loop.c
> @@ -267,6 +267,7 @@ void cpu_loop(CPUPPCState *env)
>              queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
>              break;
>          case POWERPC_EXCP_SYSCALL:  /* System call exception                 */
> +        case POWERPC_EXCP_SYSCALL_VECTORED:
>              cpu_abort(cs, "Syscall exception while in user mode. "
>                        "Aborting\n");
>              break;
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index 6b6dd7e483..df5c30160d 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -127,8 +127,9 @@ enum {
>      POWERPC_EXCP_SDOOR_HV = 100,
>      /* ISA 3.00 additions */
>      POWERPC_EXCP_HVIRT    = 101,
> +    POWERPC_EXCP_SYSCALL_VECTORED = 102, /* scv exception                     */
>      /* EOL                                                                   */
> -    POWERPC_EXCP_NB       = 102,
> +    POWERPC_EXCP_NB       = 103,
>      /* QEMU exceptions: used internally during code translation              */
>      POWERPC_EXCP_STOP         = 0x200, /* stop translation                   */
>      POWERPC_EXCP_BRANCH       = 0x201, /* branch instruction                 */
> @@ -478,6 +479,7 @@ typedef struct ppc_v3_pate_t {
>  /* Facility Status and Control (FSCR) bits */
>  #define FSCR_EBB        (63 - 56) /* Event-Based Branch Facility */
>  #define FSCR_TAR        (63 - 55) /* Target Address Register */
> +#define FSCR_SCV        (63 - 51) /* System call vectored */
>  /* Interrupt cause mask and position in FSCR. HFSCR has the same format */
>  #define FSCR_IC_MASK    (0xFFULL)
>  #define FSCR_IC_POS     (63 - 7)
> @@ -487,6 +489,7 @@ typedef struct ppc_v3_pate_t {
>  #define FSCR_IC_TM          5
>  #define FSCR_IC_EBB         7
>  #define FSCR_IC_TAR         8
> +#define FSCR_IC_SCV        12
>  
>  /* Exception state register bits definition                                  */
>  #define ESR_PIL   PPC_BIT(36) /* Illegal Instruction                    */
> @@ -554,6 +557,8 @@ enum {
>      POWERPC_FLAG_VSX      = 0x00080000,
>      /* Has Transaction Memory (ISA 2.07)                                     */
>      POWERPC_FLAG_TM       = 0x00100000,
> +    /* Has SCV (ISA 3.00)                                                    */
> +    POWERPC_FLAG_SCV      = 0x00200000,
>  };
>  
>  /*****************************************************************************/
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index f052979664..170b3be4c4 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -67,6 +67,18 @@ static inline void dump_syscall(CPUPPCState *env)
>                    ppc_dump_gpr(env, 8), env->nip);
>  }
>  
> +static inline void dump_syscall_vectored(CPUPPCState *env)
> +{
> +    qemu_log_mask(CPU_LOG_INT, "syscall r0=%016" PRIx64
> +                  " r3=%016" PRIx64 " r4=%016" PRIx64 " r5=%016" PRIx64
> +                  " r6=%016" PRIx64 " r7=%016" PRIx64 " r8=%016" PRIx64
> +                  " nip=" TARGET_FMT_lx "\n",
> +                  ppc_dump_gpr(env, 0), ppc_dump_gpr(env, 3),
> +                  ppc_dump_gpr(env, 4), ppc_dump_gpr(env, 5),
> +                  ppc_dump_gpr(env, 6), ppc_dump_gpr(env, 7),
> +                  ppc_dump_gpr(env, 8), env->nip);
> +}
> +
>  static inline void dump_hcall(CPUPPCState *env)
>  {
>      qemu_log_mask(CPU_LOG_INT, "hypercall r3=%016" PRIx64
> @@ -185,7 +197,7 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>      CPUState *cs = CPU(cpu);
>      CPUPPCState *env = &cpu->env;
>      target_ulong msr, new_msr, vector;
> -    int srr0, srr1, asrr0, asrr1, lev, ail;
> +    int srr0, srr1, asrr0, asrr1, lev = -1, ail;
>      bool lpes0;
>  
>      qemu_log_mask(CPU_LOG_INT, "Raise exception at " TARGET_FMT_lx
> @@ -421,6 +433,13 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>              new_msr |= (target_ulong)MSR_HVB;
>          }
>          break;
> +    case POWERPC_EXCP_SYSCALL_VECTORED: /* scv exception                     */
> +        lev = env->error_code;
> +        dump_syscall_vectored(env);
> +        env->nip += 4;
> +        new_msr |= env->msr & ((target_ulong)1 << MSR_EE);
> +        new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
> +        break;
>      case POWERPC_EXCP_FPU:       /* Floating-point unavailable exception     */
>      case POWERPC_EXCP_APU:       /* Auxiliary processor unavailable          */
>      case POWERPC_EXCP_DECR:      /* Decrementer exception                    */
> @@ -724,12 +743,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>          break;
>      }
>  
> -    /* Save PC */
> -    env->spr[srr0] = env->nip;
> -
> -    /* Save MSR */
> -    env->spr[srr1] = msr;
> -
>      /* Sanity check */
>      if (!(env->msr_mask & MSR_HVB)) {
>          if (new_msr & MSR_HVB) {
> @@ -742,14 +755,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>          }
>      }
>  
> -    /* If any alternate SRR register are defined, duplicate saved values */
> -    if (asrr0 != -1) {
> -        env->spr[asrr0] = env->spr[srr0];
> -    }
> -    if (asrr1 != -1) {
> -        env->spr[asrr1] = env->spr[srr1];
> -    }
> -
>      /*
>       * Sort out endianness of interrupt, this differs depending on the
>       * CPU, the HV mode, etc...
> @@ -784,14 +789,6 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>      }
>  #endif
>  
> -    /* Jump to handler */
> -    vector = env->excp_vectors[excp];
> -    if (vector == (target_ulong)-1ULL) {
> -        cpu_abort(cs, "Raised an exception without defined vector %d\n",
> -                  excp);
> -    }
> -    vector |= env->excp_prefix;
> -
>      /*
>       * AIL only works if there is no HV transition and we are running
>       * with translations enabled
> @@ -800,10 +797,21 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>          ((new_msr & MSR_HVB) && !(msr & MSR_HVB))) {
>          ail = 0;
>      }
> -    /* Handle AIL */
> -    if (ail) {
> -        new_msr |= (1 << MSR_IR) | (1 << MSR_DR);
> -        vector |= ppc_excp_vector_offset(cs, ail);
> +
> +    vector = env->excp_vectors[excp];
> +    if (vector == (target_ulong)-1ULL) {
> +        cpu_abort(cs, "Raised an exception without defined vector %d\n",
> +                  excp);
> +    }
> +
> +    vector |= env->excp_prefix;
> +
> +    /* If any alternate SRR register are defined, duplicate saved values */
> +    if (asrr0 != -1) {
> +        env->spr[asrr0] = env->nip;
> +    }
> +    if (asrr1 != -1) {
> +        env->spr[asrr1] = msr;
>      }
>  
>  #if defined(TARGET_PPC64)
> @@ -823,6 +831,37 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>      }
>  #endif
>  
> +    if (excp != POWERPC_EXCP_SYSCALL_VECTORED) {
> +        /* Save PC */
> +        env->spr[srr0] = env->nip;
> +
> +        /* Save MSR */
> +        env->spr[srr1] = msr;
> +
> +        /* Handle AIL */
> +        if (ail) {
> +            new_msr |= (1 << MSR_IR) | (1 << MSR_DR);
> +            vector |= ppc_excp_vector_offset(cs, ail);
> +        }
> +
> +#if defined(TARGET_PPC64)
> +    } else {
> +        /* scv AIL is a little different */
> +        if (ail) {
> +            new_msr |= (1 << MSR_IR) | (1 << MSR_DR);
> +        }
> +        if (ail == AIL_C000_0000_0000_4000) {
> +            vector |= 0xc000000000003000ull;
> +        } else {
> +            vector |= 0x0000000000017000ull;
> +        }
> +        vector += lev * 0x20;
> +
> +        env->lr = env->nip;
> +        env->ctr = msr;
> +#endif
> +    }
> +
>      powerpc_set_excp_state(cpu, vector, new_msr);
>  }
>  
> @@ -1160,6 +1199,11 @@ void helper_rfid(CPUPPCState *env)
>      do_rfi(env, env->spr[SPR_SRR0], env->spr[SPR_SRR1]);
>  }
>  
> +void helper_rfscv(CPUPPCState *env)
> +{
> +    do_rfi(env, env->lr, env->ctr);
> +}
> +
>  void helper_hrfid(CPUPPCState *env)
>  {
>      do_rfi(env, env->spr[SPR_HSRR0], env->spr[SPR_HSRR1]);
> diff --git a/target/ppc/helper.h b/target/ppc/helper.h
> index a95c010391..2dfa1c6942 100644
> --- a/target/ppc/helper.h
> +++ b/target/ppc/helper.h
> @@ -15,6 +15,7 @@ DEF_HELPER_1(rfmci, void, env)
>  #if defined(TARGET_PPC64)
>  DEF_HELPER_2(pminsn, void, env, i32)
>  DEF_HELPER_1(rfid, void, env)
> +DEF_HELPER_1(rfscv, void, env)
>  DEF_HELPER_1(hrfid, void, env)
>  DEF_HELPER_2(store_lpcr, void, env, tl)
>  DEF_HELPER_2(store_pcr, void, env, tl)
> diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> index 807d14faaa..9a7ae9a160 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -173,6 +173,7 @@ struct DisasContext {
>      bool vsx_enabled;
>      bool spe_enabled;
>      bool tm_enabled;
> +    bool scv_enabled;
>      bool gtse;
>      ppc_spr_t *spr_cb; /* Needed to check rights for mfspr/mtspr */
>      int singlestep_enabled;
> @@ -4012,6 +4013,24 @@ static void gen_rfid(DisasContext *ctx)
>  #endif
>  }
>  
> +#if !defined(CONFIG_USER_ONLY)
> +static void gen_rfscv(DisasContext *ctx)
> +{
> +#if defined(CONFIG_USER_ONLY)
> +    GEN_PRIV;
> +#else
> +    /* Restore CPU state */
> +    CHK_SV;
> +    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> +        gen_io_start();
> +    }
> +    gen_update_cfar(ctx, ctx->base.pc_next - 4);
> +    gen_helper_rfscv(cpu_env);
> +    gen_sync_exception(ctx);
> +#endif
> +}
> +#endif
> +
>  static void gen_hrfid(DisasContext *ctx)
>  {
>  #if defined(CONFIG_USER_ONLY)
> @@ -4030,6 +4049,7 @@ static void gen_hrfid(DisasContext *ctx)
>  #define POWERPC_SYSCALL POWERPC_EXCP_SYSCALL_USER
>  #else
>  #define POWERPC_SYSCALL POWERPC_EXCP_SYSCALL
> +#define POWERPC_SYSCALL_VECTORED POWERPC_EXCP_SYSCALL_VECTORED
>  #endif
>  static void gen_sc(DisasContext *ctx)
>  {
> @@ -4039,6 +4059,23 @@ static void gen_sc(DisasContext *ctx)
>      gen_exception_err(ctx, POWERPC_SYSCALL, lev);
>  }
>  
> +#if defined(TARGET_PPC64)
> +#if !defined(CONFIG_USER_ONLY)
> +static void gen_scv(DisasContext *ctx)
> +{
> +    uint32_t lev;
> +
> +    if (unlikely(!ctx->scv_enabled)) {
> +        gen_exception_err(ctx, POWERPC_EXCP_FU, FSCR_IC_SCV);
> +        return;
> +    }
> +
> +    lev = (ctx->opcode >> 5) & 0x7F;
> +    gen_exception_err(ctx, POWERPC_SYSCALL_VECTORED, lev);
> +}
> +#endif
> +#endif
> +
>  /***                                Trap                                   ***/
>  
>  /* Check for unconditional traps (always or never) */
> @@ -7031,6 +7068,12 @@ GEN_HANDLER(mcrf, 0x13, 0x00, 0xFF, 0x00000001, PPC_INTEGER),
>  GEN_HANDLER(rfi, 0x13, 0x12, 0x01, 0x03FF8001, PPC_FLOW),
>  #if defined(TARGET_PPC64)
>  GEN_HANDLER(rfid, 0x13, 0x12, 0x00, 0x03FF8001, PPC_64B),
> +#if !defined(CONFIG_USER_ONLY)
> +/* Top bit of opc2 corresponds with low bit of LEV, so use two handlers */
> +GEN_HANDLER_E(scv, 0x11, 0x10, 0xFF, 0x03FFF01E, PPC_NONE, PPC2_ISA300),
> +GEN_HANDLER_E(scv, 0x11, 0x00, 0xFF, 0x03FFF01E, PPC_NONE, PPC2_ISA300),
> +GEN_HANDLER_E(rfscv, 0x13, 0x12, 0x02, 0x03FF8001, PPC_NONE, PPC2_ISA300),
> +#endif
>  GEN_HANDLER_E(stop, 0x13, 0x12, 0x0b, 0x03FFF801, PPC_NONE, PPC2_ISA300),
>  GEN_HANDLER_E(doze, 0x13, 0x12, 0x0c, 0x03FFF801, PPC_NONE, PPC2_PM_ISA206),
>  GEN_HANDLER_E(nap, 0x13, 0x12, 0x0d, 0x03FFF801, PPC_NONE, PPC2_PM_ISA206),
> @@ -7038,7 +7081,9 @@ GEN_HANDLER_E(sleep, 0x13, 0x12, 0x0e, 0x03FFF801, PPC_NONE, PPC2_PM_ISA206),
>  GEN_HANDLER_E(rvwinkle, 0x13, 0x12, 0x0f, 0x03FFF801, PPC_NONE, PPC2_PM_ISA206),
>  GEN_HANDLER(hrfid, 0x13, 0x12, 0x08, 0x03FF8001, PPC_64H),
>  #endif
> -GEN_HANDLER(sc, 0x11, 0xFF, 0xFF, 0x03FFF01D, PPC_FLOW),
> +/* Top bit of opc2 corresponds with low bit of LEV, so use two handlers */
> +GEN_HANDLER(sc, 0x11, 0x11, 0xFF, 0x03FFF01D, PPC_FLOW),
> +GEN_HANDLER(sc, 0x11, 0x01, 0xFF, 0x03FFF01D, PPC_FLOW),
>  GEN_HANDLER(tw, 0x1F, 0x04, 0x00, 0x00000001, PPC_FLOW),
>  GEN_HANDLER(twi, 0x03, 0xFF, 0xFF, 0x00000000, PPC_FLOW),
>  #if defined(TARGET_PPC64)
> @@ -7817,6 +7862,11 @@ static void ppc_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
>      } else {
>          ctx->vsx_enabled = false;
>      }
> +    if ((env->flags & POWERPC_FLAG_SCV) && (env->spr[SPR_FSCR] & (1ull << FSCR_SCV))) {
> +        ctx->scv_enabled = true;
> +    } else {
> +        ctx->scv_enabled = false;
> +    }
>  #if defined(TARGET_PPC64)
>      if ((env->flags & POWERPC_FLAG_TM) && msr_tm) {
>          ctx->tm_enabled = !!msr_tm;
> diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c
> index fd763e588e..18f275d4fa 100644
> --- a/target/ppc/translate_init.inc.c
> +++ b/target/ppc/translate_init.inc.c
> @@ -3382,6 +3382,7 @@ static void init_excp_POWER9(CPUPPCState *env)
>  
>  #if !defined(CONFIG_USER_ONLY)
>      env->excp_vectors[POWERPC_EXCP_HVIRT]    = 0x00000EA0;
> +    env->excp_vectors[POWERPC_EXCP_SYSCALL_VECTORED] = 0x00000000;
>  #endif
>  }
>  
> @@ -9030,7 +9031,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void *data)
>      pcc->flags = POWERPC_FLAG_VRE | POWERPC_FLAG_SE |
>                   POWERPC_FLAG_BE | POWERPC_FLAG_PMM |
>                   POWERPC_FLAG_BUS_CLK | POWERPC_FLAG_CFAR |
> -                 POWERPC_FLAG_VSX | POWERPC_FLAG_TM;
> +                 POWERPC_FLAG_VSX | POWERPC_FLAG_TM | POWERPC_FLAG_SCV;
>      pcc->l1_dcache_size = 0x8000;
>      pcc->l1_icache_size = 0x8000;
>      pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_lpcr;