Commit 1a8e80d7 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg-arm: Avoid ldrd/strd for user-only emulation 



The arm ldrd/strd insns must cause alignment traps, whereas
at least for armv7 ldr/str must handle unaligned operations.

While this is hardly the only problem facing user-only emu,
this solves one problem for i386 on armv7 emulation.

Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reported-by: default avatarHuw Davies <huw@codeweavers.com>
Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent 9c5793c5

tcg/arm/tcg-target.c

+17 −4
Original line number Diff line number Diff line
@@ -60,6 +60,13 @@ static int arm_arch = __ARM_ARCH; 
bool use_idiv_instructions;

#endif



/* ??? Ought to think about changing CONFIG_SOFTMMU to always defined.  */

#ifdef CONFIG_SOFTMMU

# define USING_SOFTMMU 1

#else

# define USING_SOFTMMU 0

#endif



#ifndef NDEBUG

static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {

    "%r0",
@@ -1404,7 +1411,9 @@ static inline void tcg_out_qemu_ld_index(TCGContext *s, TCGMemOp opc, 
            TCGReg dl = (bswap ? datahi : datalo);

            TCGReg dh = (bswap ? datalo : datahi);



            if (use_armv6_instructions && (dl & 1) == 0 && dh == dl + 1) {

            /* Avoid ldrd for user-only emulation, to handle unaligned.  */

            if (USING_SOFTMMU && use_armv6_instructions

                && (dl & 1) == 0 && dh == dl + 1) {

                tcg_out_ldrd_r(s, COND_AL, dl, addrlo, addend);

            } else if (dl != addend) {

                tcg_out_ld32_rwb(s, COND_AL, dl, addend, addrlo);
@@ -1463,7 +1472,9 @@ static inline void tcg_out_qemu_ld_direct(TCGContext *s, TCGMemOp opc, 
            TCGReg dl = (bswap ? datahi : datalo);

            TCGReg dh = (bswap ? datalo : datahi);



            if (use_armv6_instructions && (dl & 1) == 0 && dh == dl + 1) {

            /* Avoid ldrd for user-only emulation, to handle unaligned.  */

            if (USING_SOFTMMU && use_armv6_instructions

                && (dl & 1) == 0 && dh == dl + 1) {

                tcg_out_ldrd_8(s, COND_AL, dl, addrlo, 0);

            } else if (dl == addrlo) {

                tcg_out_ld32_12(s, COND_AL, dh, addrlo, bswap ? 0 : 4);
@@ -1548,12 +1559,13 @@ static inline void tcg_out_qemu_st_index(TCGContext *s, int cond, TCGMemOp opc, 
        }

        break;

    case MO_64:

        /* Avoid strd for user-only emulation, to handle unaligned.  */

        if (bswap) {

            tcg_out_bswap32(s, cond, TCG_REG_R0, datahi);

            tcg_out_st32_rwb(s, cond, TCG_REG_R0, addend, addrlo);

            tcg_out_bswap32(s, cond, TCG_REG_R0, datalo);

            tcg_out_st32_12(s, cond, TCG_REG_R0, addend, 4);

        } else if (use_armv6_instructions

        } else if (USING_SOFTMMU && use_armv6_instructions

                   && (datalo & 1) == 0 && datahi == datalo + 1) {

            tcg_out_strd_r(s, cond, datalo, addrlo, addend);

        } else {
@@ -1592,12 +1604,13 @@ static inline void tcg_out_qemu_st_direct(TCGContext *s, TCGMemOp opc, 
        }

        break;

    case MO_64:

        /* Avoid strd for user-only emulation, to handle unaligned.  */

        if (bswap) {

            tcg_out_bswap32(s, COND_AL, TCG_REG_R0, datahi);

            tcg_out_st32_12(s, COND_AL, TCG_REG_R0, addrlo, 0);

            tcg_out_bswap32(s, COND_AL, TCG_REG_R0, datalo);

            tcg_out_st32_12(s, COND_AL, TCG_REG_R0, addrlo, 4);

        } else if (use_armv6_instructions

        } else if (USING_SOFTMMU && use_armv6_instructions

                   && (datalo & 1) == 0 && datahi == datalo + 1) {

            tcg_out_strd_8(s, COND_AL, datalo, addrlo, 0);

        } else {