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target/arm: Convert load/store exclusive and ordered to decodetree 
Convert the instructions in the load/store exclusive (STXR,
STLXR, LDXR, LDAXR) and load/store ordered (STLR, STLLR,
LDAR, LDLAR) to decodetree.

Note that for STLR, STLLR, LDAR, LDLAR this fixes an under-decoding
in the legacy decoder where we were not checking that the RES1 bits
in the Rs and Rt2 fields were set.

The new function ldst_iss_sf() is equivalent to the existing
disas_ldst_compute_iss_sf(), but it takes the pre-decoded 'ext' field
rather than taking an undecoded two-bit opc field and extracting
'ext' from it. Once all the loads and stores have been converted
to decodetree disas_ldst_compute_iss_sf() will be unused and
can be deleted.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230602155223.2040685-9-peter.maydell@linaro.org
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pm215 committed Jun 19, 2023
1 parent a97d3c1 commit 84693e6
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Showing 2 changed files with 103 additions and 62 deletions.
11 changes: 11 additions & 0 deletions target/arm/tcg/a64.decode
View file
Expand Up @@ -230,3 +230,14 @@ HLT 1101 0100 010 ................ 000 00 @i16
# DCPS1 1101 0100 101 ................ 000 01 @i16
# DCPS2 1101 0100 101 ................ 000 10 @i16
# DCPS3 1101 0100 101 ................ 000 11 @i16

# Loads and stores

&stxr rn rt rt2 rs sz lasr
&stlr rn rt sz lasr
@stxr sz:2 ...... ... rs:5 lasr:1 rt2:5 rn:5 rt:5 &stxr
@stlr sz:2 ...... ... ..... lasr:1 ..... rn:5 rt:5 &stlr
STXR .. 001000 000 ..... . ..... ..... ..... @stxr # inc STLXR
LDXR .. 001000 010 ..... . ..... ..... ..... @stxr # inc LDAXR
STLR .. 001000 100 11111 . 11111 ..... ..... @stlr # inc STLLR
LDAR .. 001000 110 11111 . 11111 ..... ..... @stlr # inc LDLAR
154 changes: 92 additions & 62 deletions target/arm/tcg/translate-a64.c
View file
Expand Up @@ -2652,6 +2652,95 @@ static bool disas_ldst_compute_iss_sf(int size, bool is_signed, int opc)
return regsize == 64;
}

static bool ldst_iss_sf(int size, bool sign, bool ext)
{

if (sign) {
/*
* Signed loads are 64 bit results if we are not going to
* do a zero-extend from 32 to 64 after the load.
* (For a store, sign and ext are always false.)
*/
return !ext;
} else {
/* Unsigned loads/stores work at the specified size */
return size == MO_64;
}
}

static bool trans_STXR(DisasContext *s, arg_stxr *a)
{
if (a->rn == 31) {
gen_check_sp_alignment(s);
}
if (a->lasr) {
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_STRL);
}
gen_store_exclusive(s, a->rs, a->rt, a->rt2, a->rn, a->sz, false);
return true;
}

static bool trans_LDXR(DisasContext *s, arg_stxr *a)
{
if (a->rn == 31) {
gen_check_sp_alignment(s);
}
gen_load_exclusive(s, a->rt, a->rt2, a->rn, a->sz, false);
if (a->lasr) {
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_LDAQ);
}
return true;
}

static bool trans_STLR(DisasContext *s, arg_stlr *a)
{
TCGv_i64 clean_addr;
MemOp memop;
bool iss_sf = ldst_iss_sf(a->sz, false, false);

/*
* StoreLORelease is the same as Store-Release for QEMU, but
* needs the feature-test.
*/
if (!a->lasr && !dc_isar_feature(aa64_lor, s)) {
return false;
}
/* Generate ISS for non-exclusive accesses including LASR. */
if (a->rn == 31) {
gen_check_sp_alignment(s);
}
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_STRL);
memop = check_ordered_align(s, a->rn, 0, true, a->sz);
clean_addr = gen_mte_check1(s, cpu_reg_sp(s, a->rn),
true, a->rn != 31, memop);
do_gpr_st(s, cpu_reg(s, a->rt), clean_addr, memop, true, a->rt,
iss_sf, a->lasr);
return true;
}

static bool trans_LDAR(DisasContext *s, arg_stlr *a)
{
TCGv_i64 clean_addr;
MemOp memop;
bool iss_sf = ldst_iss_sf(a->sz, false, false);

/* LoadLOAcquire is the same as Load-Acquire for QEMU. */
if (!a->lasr && !dc_isar_feature(aa64_lor, s)) {
return false;
}
/* Generate ISS for non-exclusive accesses including LASR. */
if (a->rn == 31) {
gen_check_sp_alignment(s);
}
memop = check_ordered_align(s, a->rn, 0, false, a->sz);
clean_addr = gen_mte_check1(s, cpu_reg_sp(s, a->rn),
false, a->rn != 31, memop);
do_gpr_ld(s, cpu_reg(s, a->rt), clean_addr, memop, false, true,
a->rt, iss_sf, a->lasr);
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_LDAQ);
return true;
}

/* Load/store exclusive
*
* 31 30 29 24 23 22 21 20 16 15 14 10 9 5 4 0
Expand All @@ -2674,70 +2763,8 @@ static void disas_ldst_excl(DisasContext *s, uint32_t insn)
int is_lasr = extract32(insn, 15, 1);
int o2_L_o1_o0 = extract32(insn, 21, 3) * 2 | is_lasr;
int size = extract32(insn, 30, 2);
TCGv_i64 clean_addr;
MemOp memop;

switch (o2_L_o1_o0) {
case 0x0: /* STXR */
case 0x1: /* STLXR */
if (rn == 31) {
gen_check_sp_alignment(s);
}
if (is_lasr) {
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_STRL);
}
gen_store_exclusive(s, rs, rt, rt2, rn, size, false);
return;

case 0x4: /* LDXR */
case 0x5: /* LDAXR */
if (rn == 31) {
gen_check_sp_alignment(s);
}
gen_load_exclusive(s, rt, rt2, rn, size, false);
if (is_lasr) {
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_LDAQ);
}
return;

case 0x8: /* STLLR */
if (!dc_isar_feature(aa64_lor, s)) {
break;
}
/* StoreLORelease is the same as Store-Release for QEMU. */
/* fall through */
case 0x9: /* STLR */
/* Generate ISS for non-exclusive accesses including LASR. */
if (rn == 31) {
gen_check_sp_alignment(s);
}
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_STRL);
memop = check_ordered_align(s, rn, 0, true, size);
clean_addr = gen_mte_check1(s, cpu_reg_sp(s, rn),
true, rn != 31, memop);
do_gpr_st(s, cpu_reg(s, rt), clean_addr, memop, true, rt,
disas_ldst_compute_iss_sf(size, false, 0), is_lasr);
return;

case 0xc: /* LDLAR */
if (!dc_isar_feature(aa64_lor, s)) {
break;
}
/* LoadLOAcquire is the same as Load-Acquire for QEMU. */
/* fall through */
case 0xd: /* LDAR */
/* Generate ISS for non-exclusive accesses including LASR. */
if (rn == 31) {
gen_check_sp_alignment(s);
}
memop = check_ordered_align(s, rn, 0, false, size);
clean_addr = gen_mte_check1(s, cpu_reg_sp(s, rn),
false, rn != 31, memop);
do_gpr_ld(s, cpu_reg(s, rt), clean_addr, memop, false, true,
rt, disas_ldst_compute_iss_sf(size, false, 0), is_lasr);
tcg_gen_mb(TCG_MO_ALL | TCG_BAR_LDAQ);
return;

case 0x2: case 0x3: /* CASP / STXP */
if (size & 2) { /* STXP / STLXP */
if (rn == 31) {
Expand Down Expand Up @@ -2787,6 +2814,9 @@ static void disas_ldst_excl(DisasContext *s, uint32_t insn)
return;
}
break;
default:
/* Handled in decodetree */
break;
}
unallocated_encoding(s);
}
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