Re: [Qemu-devel] [PATCH v5 21/30] target-ppc: Add POWER8's FSCR SPR

[Tom Musta <tommusta@gmail.com>]

On 6/4/2014 7:50 AM, Alexey Kardashevskiy wrote:
> This adds an FSCR (Facility Status and Control Register) SPR. This defines
> names for FSCR bits.
> 
> This defines new exception type - POWERPC_EXCP_FU - "facility unavailable" (FU).
> This registers an interrupt vector for it at 0xF60 as PowerISA defines.
> 
> This adds a TCG helper_fscr_facility_check() helper to raise an exception
> if the facility is not enabled. It updates the interrupt cause field
> in FSCR. This adds a TCG translation block generation code. The helper
> may be used for HFSCR too as it has the same format.
> 
> The helper raising FU exceptions is not used by this patch but will be
> in the next ones.
> 
> This adds gen_update_current_nip() to update NIP in DisasContext.
> This helper is not used now and will be called before checking for
> a condition for throwing an FU exception.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> Changes:
> v4:
> * added gen_update_current_nip()
> * it is gen_spr_power8_fscr() now instead of gen_spr_power8_common()
> * added "facility unavailable" exception vector at 0xF60
> ---
>  target-ppc/cpu.h            | 16 ++++++++++++++++
>  target-ppc/excp_helper.c    |  5 +++++
>  target-ppc/helper.h         |  1 +
>  target-ppc/misc_helper.c    | 27 +++++++++++++++++++++++++++
>  target-ppc/translate.c      |  7 +++++++
>  target-ppc/translate_init.c | 10 ++++++++++
>  6 files changed, 66 insertions(+)
> 
> diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
> index 3a578e6..7d566f3 100644
> --- a/target-ppc/cpu.h
> +++ b/target-ppc/cpu.h
> @@ -238,6 +238,7 @@ enum {
>      POWERPC_EXCP_DTLBE    = 93, /* Data TLB error                            */
>      /* VSX Unavailable (Power ISA 2.06 and later)                            */
>      POWERPC_EXCP_VSXU     = 94, /* VSX Unavailable                           */
> +    POWERPC_EXCP_FU       = 95, /* Facility Unavailable                      */
>      /* EOL                                                                   */
>      POWERPC_EXCP_NB       = 96,
>      /* QEMU exceptions: used internally during code translation              */
> @@ -516,6 +517,19 @@ struct ppc_slb_t {
>  #endif
>  #endif
>  
> +/* Facility Status and Control (FSCR) bits */
> +#define FSCR_EBB        (63 - 56) /* Event-Based Branch Facility */
> +#define FSCR_TAR        (63 - 55) /* Target Address Register */
> +/* Interrupt cause mask and position in FSCR. HFSCR has the same format */
> +#define FSCR_IC_MASK    (0xFFULL)
> +#define FSCR_IC_POS     (63 - 7)
> +#define FSCR_IC_DSCR_SPR3   2
> +#define FSCR_IC_PMU         3
> +#define FSCR_IC_BHRB        4
> +#define FSCR_IC_TM          5
> +#define FSCR_IC_EBB         7
> +#define FSCR_IC_TAR         8
> +
>  /* Exception state register bits definition                                  */
>  #define ESR_PIL   (1 << (63 - 36)) /* Illegal Instruction                    */
>  #define ESR_PPR   (1 << (63 - 37)) /* Privileged Instruction                 */
> @@ -1104,6 +1118,7 @@ do {                                            \
>  /*****************************************************************************/
>  PowerPCCPU *cpu_ppc_init(const char *cpu_model);
>  void ppc_translate_init(void);
> +void gen_update_current_nip(void *opaque);
>  int cpu_ppc_exec (CPUPPCState *s);
>  /* you can call this signal handler from your SIGBUS and SIGSEGV
>     signal handlers to inform the virtual CPU of exceptions. non zero
> @@ -1272,6 +1287,7 @@ static inline int cpu_mmu_index (CPUPPCState *env)
>  #define SPR_CTRL              (0x098)
>  #define SPR_MPC_CMPE          (0x098)
>  #define SPR_MPC_CMPF          (0x099)
> +#define SPR_FSCR              (0x099)
>  #define SPR_MPC_CMPG          (0x09A)
>  #define SPR_MPC_CMPH          (0x09B)
>  #define SPR_MPC_LCTRL1        (0x09C)
> diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
> index a0c9fdc..4b9e8fc 100644
> --- a/target-ppc/excp_helper.c
> +++ b/target-ppc/excp_helper.c
> @@ -398,6 +398,11 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>              new_msr |= (target_ulong)MSR_HVB;
>          }
>          goto store_current;
> +    case POWERPC_EXCP_FU:         /* Facility unavailable exception          */
> +        if (lpes1 == 0) {
> +            new_msr |= (target_ulong)MSR_HVB;
> +        }
> +        goto store_current;
>      case POWERPC_EXCP_PIT:       /* Programmable interval timer interrupt    */
>          LOG_EXCP("PIT exception\n");
>          goto store_next;
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index 5ee4706..c1417ea 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -577,6 +577,7 @@ DEF_HELPER_3(store_dcr, void, env, tl, tl)
>  
>  DEF_HELPER_2(load_dump_spr, void, env, i32)
>  DEF_HELPER_2(store_dump_spr, void, env, i32)
> +DEF_HELPER_4(fscr_facility_check, void, env, i32, i32, i32)
>  DEF_HELPER_1(load_tbl, tl, env)
>  DEF_HELPER_1(load_tbu, tl, env)
>  DEF_HELPER_1(load_atbl, tl, env)
> diff --git a/target-ppc/misc_helper.c b/target-ppc/misc_helper.c
> index 7331b1b..554831f 100644
> --- a/target-ppc/misc_helper.c
> +++ b/target-ppc/misc_helper.c
> @@ -34,6 +34,33 @@ void helper_store_dump_spr(CPUPPCState *env, uint32_t sprn)
>      qemu_log("Write SPR %d %03x <= " TARGET_FMT_lx "\n", sprn, sprn,
>               env->spr[sprn]);
>  }
> +
> +#ifdef TARGET_PPC64
> +static void raise_fu_exception(CPUPPCState *env, uint32_t bit,
> +                               uint32_t sprn, uint32_t cause)
> +{
> +    qemu_log("Facility SPR %d is unavailable (SPR FSCR:%d)\n", sprn, bit);
> +
> +    env->spr[SPR_FSCR] &= ~((target_ulong)FSCR_IC_MASK << FSCR_IC_POS);
> +    cause &= FSCR_IC_MASK;
> +    env->spr[SPR_FSCR] |= (target_ulong)cause << FSCR_IC_POS;
> +
> +    helper_raise_exception_err(env, POWERPC_EXCP_FU, 0);
> +}
> +#endif
> +
> +void helper_fscr_facility_check(CPUPPCState *env, uint32_t bit,
> +                                uint32_t sprn, uint32_t cause)
> +{
> +#ifdef TARGET_PPC64
> +    if (env->spr[SPR_FSCR] & (1ULL << bit)) {
> +        /* Facility is enabled, continue */
> +        return;
> +    }
> +    raise_fu_exception(env, bit, sprn, cause);
> +#endif
> +}
> +
>  #if !defined(CONFIG_USER_ONLY)
>  
>  void helper_store_sdr1(CPUPPCState *env, target_ulong val)
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index 5407300..2de362c 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -289,6 +289,13 @@ static inline void gen_update_nip(DisasContext *ctx, target_ulong nip)
>      tcg_gen_movi_tl(cpu_nip, nip);
>  }
>  
> +void gen_update_current_nip(void *opaque)
> +{
> +    DisasContext *ctx = opaque;
> +
> +    tcg_gen_movi_tl(cpu_nip, ctx->nip);
> +}
> +
>  static inline void gen_exception_err(DisasContext *ctx, uint32_t excp, uint32_t error)
>  {
>      TCGv_i32 t0, t1;
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index 1df69e0..4e139b4 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -3080,6 +3080,7 @@ static void init_excp_POWER7 (CPUPPCState *env)
>      env->excp_vectors[POWERPC_EXCP_PERFM]    = 0x00000F00;
>      env->excp_vectors[POWERPC_EXCP_VPU]      = 0x00000F20;
>      env->excp_vectors[POWERPC_EXCP_VSXU]     = 0x00000F40;
> +    env->excp_vectors[POWERPC_EXCP_FU]       = 0x00000F60;
>      env->excp_vectors[POWERPC_EXCP_IABR]     = 0x00001300;
>      env->excp_vectors[POWERPC_EXCP_MAINT]    = 0x00001600;
>      env->excp_vectors[POWERPC_EXCP_VPUA]     = 0x00001700;
> @@ -7586,6 +7587,14 @@ static void gen_spr_power8_tce_address_control(CPUPPCState *env)
>                   0x00000000);
>  }
>  
> +static void gen_spr_power8_fscr(CPUPPCState *env)
> +{
> +    spr_register_kvm(env, SPR_FSCR, "FSCR",
> +                     SPR_NOACCESS, SPR_NOACCESS,
> +                     &spr_read_generic, &spr_write_generic,
> +                     KVM_REG_PPC_FSCR, 0x00000000);
> +}
> +
>  static void init_proc_book3s_64(CPUPPCState *env, int version)
>  {
>      gen_spr_ne_601(env);
> @@ -7631,6 +7640,7 @@ static void init_proc_book3s_64(CPUPPCState *env, int version)
>      if (version >= BOOK3S_CPU_POWER8) {
>          gen_spr_power8_tce_address_control(env);
>          gen_spr_power8_ids(env);
> +        gen_spr_power8_fscr(env);
>      }
>  #if !defined(CONFIG_USER_ONLY)
>      switch (version) {
> 
Reviewed-by: Tom Musta <tommusta@gmail.com>