Re: [Qemu-devel] [PATCH v4 22/32] target-xtensa: implement unaligned exception option

[Blue Swirl <blauwirbel@gmail.com>]

On Thu, Sep 1, 2011 at 8:45 PM, Max Filippov <jcmvbkbc@gmail.com> wrote:
> See ISA, 4.4.4 for details.
>
> Correct (aligned as per ISA) address for unaligned access is generated
> in case this option is not enabled.
>
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
>  target-xtensa/helper.c    |    4 ++-
>  target-xtensa/op_helper.c |   26 ++++++++++++++++++++++++
>  target-xtensa/translate.c |   47 ++++++++++++++++++++++++++++++++++++++++++--
>  3 files changed, 73 insertions(+), 4 deletions(-)
>
> diff --git a/target-xtensa/helper.c b/target-xtensa/helper.c
> index 074207f..bcd6c77 100644
> --- a/target-xtensa/helper.c
> +++ b/target-xtensa/helper.c
> @@ -45,7 +45,9 @@ void cpu_reset(CPUXtensaState *env)
>  static const XtensaConfig core_config[] = {
>     {
>         .name = "sample-xtensa-core",
> -        .options = -1,
> +        .options = -1 ^
> +            (XTENSA_OPTION_BIT(XTENSA_OPTION_HW_ALIGNMENT) |
> +             XTENSA_OPTION_BIT(XTENSA_OPTION_MMU)),
>         .nareg = 64,
>         .ndepc = 1,
>         .excm_level = 16,
> diff --git a/target-xtensa/op_helper.c b/target-xtensa/op_helper.c
> index 26d2d2e..8577f5d 100644
> --- a/target-xtensa/op_helper.c
> +++ b/target-xtensa/op_helper.c
> @@ -30,6 +30,10 @@
>  #include "helpers.h"
>  #include "host-utils.h"
>
> +static void do_unaligned_access(target_ulong addr, int is_write, int is_user,
> +        void *retaddr);
> +
> +#define ALIGNED_ONLY
>  #define MMUSUFFIX _mmu
>
>  #define SHIFT 0
> @@ -44,6 +48,28 @@
>  #define SHIFT 3
>  #include "softmmu_template.h"
>
> +static void do_restore_state(void *pc_ptr)
> +{
> +    TranslationBlock *tb;
> +    uint32_t pc = (uint32_t)(intptr_t)pc_ptr;
> +
> +    tb = tb_find_pc(pc);
> +    if (tb) {
> +        cpu_restore_state(tb, env, pc);
> +    }
> +}
> +
> +static void do_unaligned_access(target_ulong addr, int is_write, int is_user,
> +        void *retaddr)
> +{
> +    if (xtensa_option_enabled(env->config, XTENSA_OPTION_UNALIGNED_EXCEPTION) &&
> +            !xtensa_option_enabled(env->config, XTENSA_OPTION_HW_ALIGNMENT)) {
> +        do_restore_state(retaddr);
> +        HELPER(exception_cause_vaddr)(
> +                env->pc, LOAD_STORE_ALIGNMENT_CAUSE, addr);
> +    }
> +}
> +
>  void tlb_fill(target_ulong addr, int is_write, int mmu_idx, void *retaddr)
>  {
>     tlb_set_page(cpu_single_env,
> diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
> index 7bcbe4f..ad2b699 100644
> --- a/target-xtensa/translate.c
> +++ b/target-xtensa/translate.c
> @@ -203,6 +203,16 @@ static void gen_exception_cause(DisasContext *dc, uint32_t cause)
>     tcg_temp_free(_cause);
>  }
>
> +static void gen_exception_cause_vaddr(DisasContext *dc, uint32_t cause,
> +        TCGv_i32 vaddr)
> +{
> +    TCGv_i32 _pc = tcg_const_i32(dc->pc);
> +    TCGv_i32 _cause = tcg_const_i32(cause);

Underscores.

> +    gen_helper_exception_cause_vaddr(_pc, _cause, vaddr);
> +    tcg_temp_free(_pc);
> +    tcg_temp_free(_cause);
> +}
> +
>  static void gen_check_privilege(DisasContext *dc)
>  {
>     if (dc->cring) {
> @@ -397,6 +407,23 @@ static void gen_wsr(DisasContext *dc, uint32_t sr, TCGv_i32 s)
>     }
>  }
>
> +static void gen_load_store_alignment(DisasContext *dc, int shift,
> +        TCGv_i32 addr, bool no_hw_alignment)
> +{
> +    if (!option_enabled(dc, XTENSA_OPTION_UNALIGNED_EXCEPTION)) {
> +        tcg_gen_andi_i32(addr, addr, ~0 << shift);
> +    } else if (option_enabled(dc, XTENSA_OPTION_HW_ALIGNMENT) &&
> +            no_hw_alignment) {
> +        int label = gen_new_label();
> +        TCGv_i32 tmp = tcg_temp_new_i32();
> +        tcg_gen_andi_i32(tmp, addr, ~(~0 << shift));
> +        tcg_gen_brcondi_i32(TCG_COND_EQ, tmp, 0, label);
> +        gen_exception_cause_vaddr(dc, LOAD_STORE_ALIGNMENT_CAUSE, addr);
> +        gen_set_label(label);
> +        tcg_temp_free(tmp);
> +    }
> +}
> +
>  static void disas_xtensa_insn(DisasContext *dc)
>  {
>  #define HAS_OPTION(opt) do { \
> @@ -1339,6 +1366,9 @@ static void disas_xtensa_insn(DisasContext *dc)
>  #define gen_load_store(type, shift) do { \
>             TCGv_i32 addr = tcg_temp_new_i32(); \
>             tcg_gen_addi_i32(addr, cpu_R[RRI8_S], RRI8_IMM8 << shift); \
> +            if (shift) { \
> +                gen_load_store_alignment(dc, shift, addr, false); \
> +            } \
>             tcg_gen_qemu_##type(cpu_R[RRI8_T], addr, dc->cring); \
>             tcg_temp_free(addr); \
>         } while (0)
> @@ -1468,6 +1498,7 @@ static void disas_xtensa_insn(DisasContext *dc)
>         case 9: /*L16SI*/
>             gen_load_store(ld16s, 1);
>             break;
> +#undef gen_load_store
>
>         case 10: /*MOVI*/
>             tcg_gen_movi_i32(cpu_R[RRI8_T],
> @@ -1475,9 +1506,17 @@ static void disas_xtensa_insn(DisasContext *dc)
>                     ((RRI8_S & 0x8) ? 0xfffff000 : 0));
>             break;
>
> +#define gen_load_store_no_hw_align(type) do { \
> +            TCGv_i32 addr = tcg_temp_local_new_i32(); \
> +            tcg_gen_addi_i32(addr, cpu_R[RRI8_S], RRI8_IMM8 << 2); \
> +            gen_load_store_alignment(dc, 2, addr, true); \
> +            tcg_gen_qemu_##type(cpu_R[RRI8_T], addr, dc->cring); \
> +            tcg_temp_free(addr); \
> +        } while (0)
> +
>         case 11: /*L32AIy*/
>             HAS_OPTION(XTENSA_OPTION_MP_SYNCHRO);
> -            gen_load_store(ld32u, 2); /*TODO acquire?*/
> +            gen_load_store_no_hw_align(ld32u); /*TODO acquire?*/
>             break;
>
>         case 12: /*ADDI*/
> @@ -1497,6 +1536,7 @@ static void disas_xtensa_insn(DisasContext *dc)
>
>                 tcg_gen_mov_i32(tmp, cpu_R[RRI8_T]);
>                 tcg_gen_addi_i32(addr, cpu_R[RRI8_S], RRI8_IMM8 << 2);
> +                gen_load_store_alignment(dc, 2, addr, true);
>                 tcg_gen_qemu_ld32u(cpu_R[RRI8_T], addr, dc->cring);
>                 tcg_gen_brcond_i32(TCG_COND_NE, cpu_R[RRI8_T],
>                         cpu_SR[SCOMPARE1], label);
> @@ -1511,15 +1551,15 @@ static void disas_xtensa_insn(DisasContext *dc)
>
>         case 15: /*S32RIy*/
>             HAS_OPTION(XTENSA_OPTION_MP_SYNCHRO);
> -            gen_load_store(st32, 2); /*TODO release?*/
> +            gen_load_store_no_hw_align(st32); /*TODO release?*/
>             break;
> +#undef gen_load_store_no_hw_align
>
>         default: /*reserved*/
>             RESERVED();
>             break;
>         }
>         break;
> -#undef gen_load_store
>
>     case 3: /*LSCIp*/
>         HAS_OPTION(XTENSA_OPTION_COPROCESSOR);
> @@ -1725,6 +1765,7 @@ static void disas_xtensa_insn(DisasContext *dc)
>  #define gen_narrow_load_store(type) do { \
>             TCGv_i32 addr = tcg_temp_new_i32(); \
>             tcg_gen_addi_i32(addr, cpu_R[RRRN_S], RRRN_R << 2); \
> +            gen_load_store_alignment(dc, 2, addr, false); \
>             tcg_gen_qemu_##type(cpu_R[RRRN_T], addr, dc->cring); \
>             tcg_temp_free(addr); \
>         } while (0)
> --
> 1.7.6
>
>
>