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tcg/aarch64: Simplify constraints on qemu_ld/st 
Adjust the softmmu tlb to use TMP[0-2], not any of the normally available
registers.  Since we handle overlap betwen inputs and helper arguments,
we can allow any allocatable reg.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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@rth7680
rth7680 committed May 30, 2023
1 parent da4d0d9 commit 285a691
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Showing 3 changed files with 19 additions and 29 deletions.
2 changes: 0 additions & 2 deletions tcg/aarch64/tcg-target-con-set.h
View file
Expand Up @@ -10,11 +10,9 @@
* tcg-target-con-str.h; the constraint combination is inclusive or.
*/
C_O0_I1(r)
C_O0_I2(lZ, l)
C_O0_I2(r, rA)
C_O0_I2(rZ, r)
C_O0_I2(w, r)
C_O1_I1(r, l)
C_O1_I1(r, r)
C_O1_I1(w, r)
C_O1_I1(w, w)
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1 change: 0 additions & 1 deletion tcg/aarch64/tcg-target-con-str.h
View file
Expand Up @@ -9,7 +9,6 @@
* REGS(letter, register_mask)
*/
REGS('r', ALL_GENERAL_REGS)
REGS('l', ALL_QLDST_REGS)
REGS('w', ALL_VECTOR_REGS)

/*
Expand Down
45 changes: 19 additions & 26 deletions tcg/aarch64/tcg-target.c.inc
View file
Expand Up @@ -132,14 +132,6 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
#define ALL_GENERAL_REGS 0xffffffffu
#define ALL_VECTOR_REGS 0xffffffff00000000ull

#ifdef CONFIG_SOFTMMU
#define ALL_QLDST_REGS \
(ALL_GENERAL_REGS & ~((1 << TCG_REG_X0) | (1 << TCG_REG_X1) | \
(1 << TCG_REG_X2) | (1 << TCG_REG_X3)))
#else
#define ALL_QLDST_REGS ALL_GENERAL_REGS
#endif

/* Match a constant valid for addition (12-bit, optionally shifted). */
static inline bool is_aimm(uint64_t val)
{
Expand Down Expand Up @@ -1648,7 +1640,7 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
unsigned s_bits = opc & MO_SIZE;
unsigned s_mask = (1u << s_bits) - 1;
unsigned mem_index = get_mmuidx(oi);
TCGReg x3;
TCGReg addr_adj;
TCGType mask_type;
uint64_t compare_mask;

Expand All @@ -1660,27 +1652,27 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
mask_type = (s->page_bits + s->tlb_dyn_max_bits > 32
? TCG_TYPE_I64 : TCG_TYPE_I32);

/* Load env_tlb(env)->f[mmu_idx].{mask,table} into {x0,x1}. */
/* Load env_tlb(env)->f[mmu_idx].{mask,table} into {tmp0,tmp1}. */
QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) > 0);
QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) < -512);
QEMU_BUILD_BUG_ON(offsetof(CPUTLBDescFast, mask) != 0);
QEMU_BUILD_BUG_ON(offsetof(CPUTLBDescFast, table) != 8);
tcg_out_insn(s, 3314, LDP, TCG_REG_X0, TCG_REG_X1, TCG_AREG0,
tcg_out_insn(s, 3314, LDP, TCG_REG_TMP0, TCG_REG_TMP1, TCG_AREG0,
TLB_MASK_TABLE_OFS(mem_index), 1, 0);

/* Extract the TLB index from the address into X0. */
tcg_out_insn(s, 3502S, AND_LSR, mask_type == TCG_TYPE_I64,
TCG_REG_X0, TCG_REG_X0, addr_reg,
TCG_REG_TMP0, TCG_REG_TMP0, addr_reg,
s->page_bits - CPU_TLB_ENTRY_BITS);

/* Add the tlb_table pointer, creating the CPUTLBEntry address into X1. */
tcg_out_insn(s, 3502, ADD, 1, TCG_REG_X1, TCG_REG_X1, TCG_REG_X0);
/* Add the tlb_table pointer, forming the CPUTLBEntry address in TMP1. */
tcg_out_insn(s, 3502, ADD, 1, TCG_REG_TMP1, TCG_REG_TMP1, TCG_REG_TMP0);

/* Load the tlb comparator into X0, and the fast path addend into X1. */
tcg_out_ld(s, addr_type, TCG_REG_X0, TCG_REG_X1,
/* Load the tlb comparator into TMP0, and the fast path addend into TMP1. */
tcg_out_ld(s, addr_type, TCG_REG_TMP0, TCG_REG_TMP1,
is_ld ? offsetof(CPUTLBEntry, addr_read)
: offsetof(CPUTLBEntry, addr_write));
tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_X1, TCG_REG_X1,
tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_TMP1, TCG_REG_TMP1,
offsetof(CPUTLBEntry, addend));

/*
Expand All @@ -1689,25 +1681,26 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
* cross pages using the address of the last byte of the access.
*/
if (a_mask >= s_mask) {
x3 = addr_reg;
addr_adj = addr_reg;
} else {
addr_adj = TCG_REG_TMP2;
tcg_out_insn(s, 3401, ADDI, addr_type,
TCG_REG_X3, addr_reg, s_mask - a_mask);
x3 = TCG_REG_X3;
addr_adj, addr_reg, s_mask - a_mask);
}
compare_mask = (uint64_t)s->page_mask | a_mask;

/* Store the page mask part of the address into X3. */
tcg_out_logicali(s, I3404_ANDI, addr_type, TCG_REG_X3, x3, compare_mask);
/* Store the page mask part of the address into TMP2. */
tcg_out_logicali(s, I3404_ANDI, addr_type, TCG_REG_TMP2,
addr_adj, compare_mask);

/* Perform the address comparison. */
tcg_out_cmp(s, addr_type, TCG_REG_X0, TCG_REG_X3, 0);
tcg_out_cmp(s, addr_type, TCG_REG_TMP0, TCG_REG_TMP2, 0);

/* If not equal, we jump to the slow path. */
ldst->label_ptr[0] = s->code_ptr;
tcg_out_insn(s, 3202, B_C, TCG_COND_NE, 0);

h->base = TCG_REG_X1,
h->base = TCG_REG_TMP1;
h->index = addr_reg;
h->index_ext = addr_type;
#else
Expand Down Expand Up @@ -2802,12 +2795,12 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
case INDEX_op_qemu_ld_a64_i32:
case INDEX_op_qemu_ld_a32_i64:
case INDEX_op_qemu_ld_a64_i64:
return C_O1_I1(r, l);
return C_O1_I1(r, r);
case INDEX_op_qemu_st_a32_i32:
case INDEX_op_qemu_st_a64_i32:
case INDEX_op_qemu_st_a32_i64:
case INDEX_op_qemu_st_a64_i64:
return C_O0_I2(lZ, l);
return C_O0_I2(rZ, r);

case INDEX_op_deposit_i32:
case INDEX_op_deposit_i64:
Expand Down

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