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tcg/arm: Use LDRD to load tlb mask+table

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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 <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2019-03-23 00:46:23 -07:00
parent 65b23204d6
commit 057b6e370b
1 changed files with 53 additions and 39 deletions
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92
tcg/arm/tcg-target.inc.c
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@ -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