From 057b6e370b0947613b0e829c0bb0ddf960003d15 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sat, 23 Mar 2019 00:46:23 -0700 Subject: [PATCH] tcg/arm: Use LDRD to load tlb mask+table This changes the code generation for the tlb from e.g. ldr ip, [r6, #-0x10] ldr r2, [r6, #-0xc] and ip, ip, r4, lsr #8 ldrd r0, r1, [r2, ip]! ldr r2, [r2, #0x18] to ldrd r0, r1, [r6, #-0x10] and r0, r0, r4, lsr #8 ldrd r2, r3, [r1, r0]! ldr r1, [r1, #0x18] for armv7 hosts. Rearranging the register allocation in order to avoid overlap between the two ldrd pairs causes the patch to be larger than it ordinarily would be. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- tcg/arm/tcg-target.inc.c | 92 +++++++++++++++++++++++----------------- 1 file changed, 53 insertions(+), 39 deletions(-) diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c index b066e30f0e..276e843627 100644 --- a/tcg/arm/tcg-target.inc.c +++ b/tcg/arm/tcg-target.inc.c @@ -267,6 +267,7 @@ static const char *target_parse_constraint(TCGArgConstraint *ct, tcg_regset_reset_reg(ct->u.regs, TCG_REG_R0); tcg_regset_reset_reg(ct->u.regs, TCG_REG_R1); tcg_regset_reset_reg(ct->u.regs, TCG_REG_R2); + tcg_regset_reset_reg(ct->u.regs, TCG_REG_R3); tcg_regset_reset_reg(ct->u.regs, TCG_REG_R14); #endif break; @@ -1224,6 +1225,10 @@ static TCGReg tcg_out_arg_reg64(TCGContext *s, TCGReg argreg, QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) > 0); QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) < -256); +/* These offsets are built into the LDRD below. */ +QEMU_BUILD_BUG_ON(offsetof(CPUTLBDescFast, mask) != 0); +QEMU_BUILD_BUG_ON(offsetof(CPUTLBDescFast, table) != 4); + /* Load and compare a TLB entry, leaving the flags set. Returns the register containing the addend of the tlb entry. Clobbers R0, R1, R2, TMP. */ @@ -1238,47 +1243,54 @@ static TCGReg tcg_out_tlb_read(TCGContext *s, TCGReg addrlo, TCGReg addrhi, unsigned s_bits = opc & MO_SIZE; unsigned a_bits = get_alignment_bits(opc); - /* Load tlb_mask[mmu_idx] and tlb_table[mmu_idx]. */ - tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_TMP, TCG_AREG0, mask_off); - tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_R2, TCG_AREG0, table_off); - - /* Extract the tlb index from the address into TMP. */ - tcg_out_dat_reg(s, COND_AL, ARITH_AND, TCG_REG_TMP, TCG_REG_TMP, addrlo, - SHIFT_IMM_LSR(TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS)); - /* - * Add the tlb_table pointer, creating the CPUTLBEntry address in R2. - * Load the tlb comparator into R0/R1 and the fast path addend into R2. + * We don't support inline unaligned acceses, but we can easily + * support overalignment checks. */ - if (cmp_off == 0) { - if (use_armv6_instructions && TARGET_LONG_BITS == 64) { - tcg_out_ldrd_rwb(s, COND_AL, TCG_REG_R0, TCG_REG_R2, TCG_REG_TMP); - } else { - tcg_out_ld32_rwb(s, COND_AL, TCG_REG_R0, TCG_REG_R2, TCG_REG_TMP); - } - } else { - tcg_out_dat_reg(s, COND_AL, ARITH_ADD, - TCG_REG_R2, TCG_REG_R2, TCG_REG_TMP, 0); - if (use_armv6_instructions && TARGET_LONG_BITS == 64) { - tcg_out_ldrd_8(s, COND_AL, TCG_REG_R0, TCG_REG_R2, cmp_off); - } else { - tcg_out_ld32_12(s, COND_AL, TCG_REG_R0, TCG_REG_R2, cmp_off); - } - } - if (!use_armv6_instructions && TARGET_LONG_BITS == 64) { - tcg_out_ld32_12(s, COND_AL, TCG_REG_R1, TCG_REG_R2, cmp_off + 4); - } - - /* Load the tlb addend. */ - tcg_out_ld32_12(s, COND_AL, TCG_REG_R2, TCG_REG_R2, - offsetof(CPUTLBEntry, addend)); - - /* Check alignment. We don't support inline unaligned acceses, - but we can easily support overalignment checks. */ if (a_bits < s_bits) { a_bits = s_bits; } + /* Load env_tlb(env)->f[mmu_idx].{mask,table} into {r0,r1}. */ + if (use_armv6_instructions) { + tcg_out_ldrd_8(s, COND_AL, TCG_REG_R0, TCG_AREG0, fast_off); + } else { + tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_R0, TCG_AREG0, mask_off); + tcg_out_ld(s, TCG_TYPE_I32, TCG_REG_R1, TCG_AREG0, table_off); + } + + /* Extract the tlb index from the address into R0. */ + tcg_out_dat_reg(s, COND_AL, ARITH_AND, TCG_REG_R0, TCG_REG_R0, addrlo, + SHIFT_IMM_LSR(TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS)); + + /* + * Add the tlb_table pointer, creating the CPUTLBEntry address in R1. + * Load the tlb comparator into R2/R3 and the fast path addend into R1. + */ + if (cmp_off == 0) { + if (use_armv6_instructions && TARGET_LONG_BITS == 64) { + tcg_out_ldrd_rwb(s, COND_AL, TCG_REG_R2, TCG_REG_R1, TCG_REG_R0); + } else { + tcg_out_ld32_rwb(s, COND_AL, TCG_REG_R2, TCG_REG_R1, TCG_REG_R0); + } + } else { + tcg_out_dat_reg(s, COND_AL, ARITH_ADD, + TCG_REG_R1, TCG_REG_R1, TCG_REG_R0, 0); + if (use_armv6_instructions && TARGET_LONG_BITS == 64) { + tcg_out_ldrd_8(s, COND_AL, TCG_REG_R2, TCG_REG_R1, cmp_off); + } else { + tcg_out_ld32_12(s, COND_AL, TCG_REG_R2, TCG_REG_R1, cmp_off); + } + } + if (!use_armv6_instructions && TARGET_LONG_BITS == 64) { + tcg_out_ld32_12(s, COND_AL, TCG_REG_R3, TCG_REG_R1, cmp_off + 4); + } + + /* Load the tlb addend. */ + tcg_out_ld32_12(s, COND_AL, TCG_REG_R1, TCG_REG_R1, + offsetof(CPUTLBEntry, addend)); + + /* Check alignment, check comparators. */ if (use_armv7_instructions) { tcg_target_ulong mask = ~(TARGET_PAGE_MASK | ((1 << a_bits) - 1)); int rot = encode_imm(mask); @@ -1291,22 +1303,24 @@ static TCGReg tcg_out_tlb_read(TCGContext *s, TCGReg addrlo, TCGReg addrhi, tcg_out_dat_reg(s, COND_AL, ARITH_BIC, TCG_REG_TMP, addrlo, TCG_REG_TMP, 0); } - tcg_out_dat_reg(s, COND_AL, ARITH_CMP, 0, TCG_REG_R0, TCG_REG_TMP, 0); + tcg_out_dat_reg(s, COND_AL, ARITH_CMP, 0, TCG_REG_R2, TCG_REG_TMP, 0); } else { if (a_bits) { tcg_out_dat_imm(s, COND_AL, ARITH_TST, 0, addrlo, (1 << a_bits) - 1); } + tcg_out_dat_reg(s, COND_AL, ARITH_MOV, TCG_REG_TMP, 0, addrlo, + SHIFT_IMM_LSR(TARGET_PAGE_BITS)); tcg_out_dat_reg(s, (a_bits ? COND_EQ : COND_AL), ARITH_CMP, - 0, TCG_REG_R0, TCG_REG_TMP, + 0, TCG_REG_R2, TCG_REG_TMP, SHIFT_IMM_LSL(TARGET_PAGE_BITS)); } if (TARGET_LONG_BITS == 64) { - tcg_out_dat_reg(s, COND_EQ, ARITH_CMP, 0, TCG_REG_R1, addrhi, 0); + tcg_out_dat_reg(s, COND_EQ, ARITH_CMP, 0, TCG_REG_R3, addrhi, 0); } - return TCG_REG_R2; + return TCG_REG_R1; } /* Record the context of a call to the out of line helper code for the slow