[Qemu-devel] [PATCH 1/5] tcg-aarch64: Update to helper_ret_*_mmu routines

[Claudio Fontana]

Hello
Richard,

> A minimal update to use the new helpers with the return address argument.
>
> Cc: Claudio Fontana <address@hidden>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  include/exec/exec-all.h  | 18 ------------------
>  tcg/aarch64/tcg-target.c | 28 ++++++++++++++++------------
>  2 files changed, 16 insertions(+), 30 deletions(-)
>
> diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
> index 8dd1594..3ce80d1 100644
> --- a/include/exec/exec-all.h
> +++ b/include/exec/exec-all.h
> @@ -320,24 +320,6 @@ extern uintptr_t tci_tb_ptr;
>  
>  #define GETPC()  (GETRA() - GETPC_ADJ)
>  
> -/* The LDST optimizations splits code generation into fast and slow path.
> -   In some implementations, we pass the "logical" return address manually;
> -   in others, we must infer the logical return from the true return.  */
> -#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
> -# if defined(__aarch64__)
> -#  define GETRA_LDST(RA)  tcg_getra_ldst(RA)
> -static inline uintptr_t tcg_getra_ldst(uintptr_t ra)
> -{
> -    int32_t b;
> -    ra += 4;                    /* skip one instruction */
> -    b = *(int32_t *)ra;         /* load the branch insn */
> -    b = (b << 6) >> (6 - 2);    /* extract the displacement */
> -    ra += b;                    /* apply the displacement  */
> -    return ra;
> -}
> -# endif
> -#endif /* CONFIG_QEMU_LDST_OPTIMIZATION */
> -
>  /* ??? Delete these once they are no longer used.  */
>  bool is_tcg_gen_code(uintptr_t pc_ptr);
>  #ifdef GETRA_LDST
> diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
> index 6379df1..78e1443 100644
> --- a/tcg/aarch64/tcg-target.c
> +++ b/tcg/aarch64/tcg-target.c
> @@ -778,22 +778,24 @@ static inline void tcg_out_nop(TCGContext *s)
>  }
>  
>  #ifdef CONFIG_SOFTMMU
> -/* helper signature: helper_ld_mmu(CPUState *env, target_ulong addr,
> -   int mmu_idx) */
> +/* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr,
> + *                                     int mmu_idx, uintptr_t ra)
> + */
>  static const void * const qemu_ld_helpers[4] = {
> -    helper_ldb_mmu,
> -    helper_ldw_mmu,
> -    helper_ldl_mmu,
> -    helper_ldq_mmu,
> +    helper_ret_ldub_mmu,
> +    helper_ret_lduw_mmu,
> +    helper_ret_ldul_mmu,
> +    helper_ret_ldq_mmu,
>  };
>  
> -/* helper signature: helper_st_mmu(CPUState *env, target_ulong addr,
> -   uintxx_t val, int mmu_idx) */
> +/* helper signature: helper_ret_st_mmu(CPUState *env, target_ulong addr,
> + *                                     uintxx_t val, int mmu_idx, uintptr_t 
> ra)
> + */
>  static const void * const qemu_st_helpers[4] = {
> -    helper_stb_mmu,
> -    helper_stw_mmu,
> -    helper_stl_mmu,
> -    helper_stq_mmu,
> +    helper_ret_stb_mmu,
> +    helper_ret_stw_mmu,
> +    helper_ret_stl_mmu,
> +    helper_ret_stq_mmu,
>  };
>  
>  static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
> @@ -802,6 +804,7 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, 
> TCGLabelQemuLdst *lb)
>      tcg_out_movr(s, 1, TCG_REG_X0, TCG_AREG0);
>      tcg_out_movr(s, (TARGET_LONG_BITS == 64), TCG_REG_X1, lb->addrlo_reg);
>      tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_X2, lb->mem_index);
> +    tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_X3, (tcg_target_long)lb->raddr);
>      tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP,
>                   (tcg_target_long)qemu_ld_helpers[lb->opc & 3]);
>      tcg_out_callr(s, TCG_REG_TMP);
> @@ -822,6 +825,7 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, 
> TCGLabelQemuLdst *lb)
>      tcg_out_movr(s, (TARGET_LONG_BITS == 64), TCG_REG_X1, lb->addrlo_reg);
>      tcg_out_movr(s, 1, TCG_REG_X2, lb->datalo_reg);
>      tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_X3, lb->mem_index);
> +    tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_X4, (tcg_target_long)lb->raddr);

At first
glance I
think we
should add
X4 to the
list of
restrictions
in
function
`target_parse_constraint':

tcg_regset_reset_reg(ct->u.regs,
TCG_REG_X4);

Otherwise
I am more
than happy
with the
intention
to remove
tcg_getra_ldst.

>      tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP,
>                   (tcg_target_long)qemu_st_helpers[lb->opc & 3]);
>      tcg_out_callr(s, TCG_REG_TMP);
> -- 
> 1.8.3.1
>

Claudio