From: Matthieu Bucchianeri <matthieu.bucchianeri@leostella.com>
To: qemu-devel@nongnu.org, qemu-ppc@nongnu.org
Cc: Matthieu Bucchianeri <matthieu.bucchianeri@leostella.com>,
david@gibson.dropbear.id.au
Subject: [PATCH] target/ppc: Fix SPE unavailable exception triggering
Date: Sat, 25 Jul 2020 12:14:36 -0700 [thread overview]
Message-ID: <20200725191436.31828-1-matthieu.bucchianeri@leostella.com> (raw)
When emulating certain floating point instructions or vector instructions on
PowerPC machines, QEMU did not properly generate the SPE/Embedded Floating-
Point Unavailable interrupt. See the buglink further below for references to
the relevant NXP documentation.
This patch fixes the behavior of some evfs* instructions that were
incorrectly emitting the interrupt.
More importantly, this patch fixes the behavior of several efd* and ev*
instructions that were not generating the interrupt. Triggering the
interrupt for these instructions fixes lazy FPU/vector context switching on
some operating systems like Linux.
Without this patch, the result of some double-precision arithmetic could be
corrupted due to the lack of proper saving and restoring of the upper
32-bit part of the general-purpose registers.
Buglink: https://bugs.launchpad.net/qemu/+bug/1888918
Buglink: https://bugs.launchpad.net/qemu/+bug/1611394
Signed-off-by: Matthieu Bucchianeri <matthieu.bucchianeri@leostella.com>
---
target/ppc/translate/spe-impl.inc.c | 101 ++++++++++++++++++----------
1 file changed, 66 insertions(+), 35 deletions(-)
diff --git a/target/ppc/translate/spe-impl.inc.c b/target/ppc/translate/spe-impl.inc.c
index 36b4d5654d..2e6e799a25 100644
--- a/target/ppc/translate/spe-impl.inc.c
+++ b/target/ppc/translate/spe-impl.inc.c
@@ -349,14 +349,24 @@ static inline void gen_evmergelohi(DisasContext *ctx)
}
static inline void gen_evsplati(DisasContext *ctx)
{
- uint64_t imm = ((int32_t)(rA(ctx->opcode) << 27)) >> 27;
+ uint64_t imm;
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
+ imm = ((int32_t)(rA(ctx->opcode) << 27)) >> 27;
tcg_gen_movi_tl(cpu_gpr[rD(ctx->opcode)], imm);
tcg_gen_movi_tl(cpu_gprh[rD(ctx->opcode)], imm);
}
static inline void gen_evsplatfi(DisasContext *ctx)
{
- uint64_t imm = rA(ctx->opcode) << 27;
+ uint64_t imm;
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
+ imm = rA(ctx->opcode) << 27;
tcg_gen_movi_tl(cpu_gpr[rD(ctx->opcode)], imm);
tcg_gen_movi_tl(cpu_gprh[rD(ctx->opcode)], imm);
@@ -389,21 +399,37 @@ static inline void gen_evsel(DisasContext *ctx)
static void gen_evsel0(DisasContext *ctx)
{
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
gen_evsel(ctx);
}
static void gen_evsel1(DisasContext *ctx)
{
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
gen_evsel(ctx);
}
static void gen_evsel2(DisasContext *ctx)
{
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
gen_evsel(ctx);
}
static void gen_evsel3(DisasContext *ctx)
{
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
gen_evsel(ctx);
}
@@ -518,6 +544,11 @@ static inline void gen_evmwsmia(DisasContext *ctx)
{
TCGv_i64 tmp;
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
+
gen_evmwsmi(ctx); /* rD := rA * rB */
tmp = tcg_temp_new_i64();
@@ -531,8 +562,13 @@ static inline void gen_evmwsmia(DisasContext *ctx)
static inline void gen_evmwsmiaa(DisasContext *ctx)
{
- TCGv_i64 acc = tcg_temp_new_i64();
- TCGv_i64 tmp = tcg_temp_new_i64();
+ TCGv_i64 acc;
+ TCGv_i64 tmp;
+
+ if (unlikely(!ctx->spe_enabled)) {
+ gen_exception(ctx, POWERPC_EXCP_SPEU);
+ return;
+ }
gen_evmwsmi(ctx); /* rD := rA * rB */
@@ -892,8 +928,14 @@ static inline void gen_##name(DisasContext *ctx) \
#define GEN_SPEFPUOP_CONV_32_64(name) \
static inline void gen_##name(DisasContext *ctx) \
{ \
- TCGv_i64 t0 = tcg_temp_new_i64(); \
- TCGv_i32 t1 = tcg_temp_new_i32(); \
+ TCGv_i64 t0; \
+ TCGv_i32 t1; \
+ if (unlikely(!ctx->spe_enabled)) { \
+ gen_exception(ctx, POWERPC_EXCP_SPEU); \
+ return; \
+ } \
+ t0 = tcg_temp_new_i64(); \
+ t1 = tcg_temp_new_i32(); \
gen_load_gpr64(t0, rB(ctx->opcode)); \
gen_helper_##name(t1, cpu_env, t0); \
tcg_gen_extu_i32_tl(cpu_gpr[rD(ctx->opcode)], t1); \
@@ -903,8 +945,14 @@ static inline void gen_##name(DisasContext *ctx) \
#define GEN_SPEFPUOP_CONV_64_32(name) \
static inline void gen_##name(DisasContext *ctx) \
{ \
- TCGv_i64 t0 = tcg_temp_new_i64(); \
- TCGv_i32 t1 = tcg_temp_new_i32(); \
+ TCGv_i64 t0; \
+ TCGv_i32 t1; \
+ if (unlikely(!ctx->spe_enabled)) { \
+ gen_exception(ctx, POWERPC_EXCP_SPEU); \
+ return; \
+ } \
+ t0 = tcg_temp_new_i64(); \
+ t1 = tcg_temp_new_i32(); \
tcg_gen_trunc_tl_i32(t1, cpu_gpr[rB(ctx->opcode)]); \
gen_helper_##name(t0, cpu_env, t1); \
gen_store_gpr64(rD(ctx->opcode), t0); \
@@ -914,7 +962,12 @@ static inline void gen_##name(DisasContext *ctx) \
#define GEN_SPEFPUOP_CONV_64_64(name) \
static inline void gen_##name(DisasContext *ctx) \
{ \
- TCGv_i64 t0 = tcg_temp_new_i64(); \
+ TCGv_i64 t0; \
+ if (unlikely(!ctx->spe_enabled)) { \
+ gen_exception(ctx, POWERPC_EXCP_SPEU); \
+ return; \
+ } \
+ t0 = tcg_temp_new_i64(); \
gen_load_gpr64(t0, rB(ctx->opcode)); \
gen_helper_##name(t0, cpu_env, t0); \
gen_store_gpr64(rD(ctx->opcode), t0); \
@@ -923,13 +976,8 @@ static inline void gen_##name(DisasContext *ctx) \
#define GEN_SPEFPUOP_ARITH2_32_32(name) \
static inline void gen_##name(DisasContext *ctx) \
{ \
- TCGv_i32 t0, t1; \
- if (unlikely(!ctx->spe_enabled)) { \
- gen_exception(ctx, POWERPC_EXCP_SPEU); \
- return; \
- } \
- t0 = tcg_temp_new_i32(); \
- t1 = tcg_temp_new_i32(); \
+ TCGv_i32 t0 = tcg_temp_new_i32(); \
+ TCGv_i32 t1 = tcg_temp_new_i32(); \
tcg_gen_trunc_tl_i32(t0, cpu_gpr[rA(ctx->opcode)]); \
tcg_gen_trunc_tl_i32(t1, cpu_gpr[rB(ctx->opcode)]); \
gen_helper_##name(t0, cpu_env, t0, t1); \
@@ -958,13 +1006,8 @@ static inline void gen_##name(DisasContext *ctx) \
#define GEN_SPEFPUOP_COMP_32(name) \
static inline void gen_##name(DisasContext *ctx) \
{ \
- TCGv_i32 t0, t1; \
- if (unlikely(!ctx->spe_enabled)) { \
- gen_exception(ctx, POWERPC_EXCP_SPEU); \
- return; \
- } \
- t0 = tcg_temp_new_i32(); \
- t1 = tcg_temp_new_i32(); \
+ TCGv_i32 t0 = tcg_temp_new_i32(); \
+ TCGv_i32 t1 = tcg_temp_new_i32(); \
\
tcg_gen_trunc_tl_i32(t0, cpu_gpr[rA(ctx->opcode)]); \
tcg_gen_trunc_tl_i32(t1, cpu_gpr[rB(ctx->opcode)]); \
@@ -1074,28 +1117,16 @@ GEN_SPEFPUOP_ARITH2_32_32(efsmul);
GEN_SPEFPUOP_ARITH2_32_32(efsdiv);
static inline void gen_efsabs(DisasContext *ctx)
{
- if (unlikely(!ctx->spe_enabled)) {
- gen_exception(ctx, POWERPC_EXCP_SPEU);
- return;
- }
tcg_gen_andi_tl(cpu_gpr[rD(ctx->opcode)], cpu_gpr[rA(ctx->opcode)],
(target_long)~0x80000000LL);
}
static inline void gen_efsnabs(DisasContext *ctx)
{
- if (unlikely(!ctx->spe_enabled)) {
- gen_exception(ctx, POWERPC_EXCP_SPEU);
- return;
- }
tcg_gen_ori_tl(cpu_gpr[rD(ctx->opcode)], cpu_gpr[rA(ctx->opcode)],
0x80000000);
}
static inline void gen_efsneg(DisasContext *ctx)
{
- if (unlikely(!ctx->spe_enabled)) {
- gen_exception(ctx, POWERPC_EXCP_SPEU);
- return;
- }
tcg_gen_xori_tl(cpu_gpr[rD(ctx->opcode)], cpu_gpr[rA(ctx->opcode)],
0x80000000);
}
--
2.17.1
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next reply other threads:[~2020-07-25 20:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-25 19:14 Matthieu Bucchianeri [this message]
2020-07-25 21:04 ` [PATCH] target/ppc: Fix SPE unavailable exception triggering no-reply
2020-07-25 21:04 ` no-reply
2020-07-26 4:07 ` Matthieu Bucchianeri
2020-07-26 10:04 ` BALATON Zoltan
2020-07-26 16:59 ` Matthieu Bucchianeri
2020-07-27 3:29 ` david
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