[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[RFC PATCH] target/i386: avoid copying junk to extended ZMMReg fields
|
From: |
Alex Bennée |
|
Subject: |
[RFC PATCH] target/i386: avoid copying junk to extended ZMMReg fields |
|
Date: |
Mon, 11 Apr 2022 15:56:09 +0100 |
When change b7711471f5 was made to alias XMMReg to ZMMReg for the
purposes of easing the handling of AVX512 registers we unwittingly
broke the SSE helpers which construct a temporary value on the stack
before copying them out. To avoid this lets encode REG_WIDTH based on
shift and convert the pointer indirection with an explicit memcpy.
An incomplete sampling of the affected instructions seems to indicate
the default behaviour for legacy SSE is "the upper bits (MAXVL-1:128)
of the corresponding YMM register destination are unmodified."
Fixes: b7711471f5 ("target-i386: make xmm_regs 512-bit wide")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/420
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
target/i386/ops_sse.h | 71 ++++++++++++++++++++++++-------------------
1 file changed, 40 insertions(+), 31 deletions(-)
diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h
index 6f1fc174b3..adfb498a71 100644
--- a/target/i386/ops_sse.h
+++ b/target/i386/ops_sse.h
@@ -28,6 +28,7 @@
#define L(n) MMX_L(n)
#define Q(n) MMX_Q(n)
#define SUFFIX _mmx
+#define REG_WIDTH 8
#else
#define Reg ZMMReg
#define XMM_ONLY(...) __VA_ARGS__
@@ -36,6 +37,7 @@
#define L(n) ZMM_L(n)
#define Q(n) ZMM_Q(n)
#define SUFFIX _xmm
+#define REG_WIDTH 16
#endif
void glue(helper_psrlw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -516,7 +518,7 @@ void glue(helper_pshufw, SUFFIX)(Reg *d, Reg *s, int order)
r.W(1) = s->W((order >> 2) & 3);
r.W(2) = s->W((order >> 4) & 3);
r.W(3) = s->W((order >> 6) & 3);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
#else
void helper_shufps(Reg *d, Reg *s, int order)
@@ -527,7 +529,7 @@ void helper_shufps(Reg *d, Reg *s, int order)
r.L(1) = d->L((order >> 2) & 3);
r.L(2) = s->L((order >> 4) & 3);
r.L(3) = s->L((order >> 6) & 3);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_shufpd(Reg *d, Reg *s, int order)
@@ -536,7 +538,7 @@ void helper_shufpd(Reg *d, Reg *s, int order)
r.Q(0) = d->Q(order & 1);
r.Q(1) = s->Q((order >> 1) & 1);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_pshufd, SUFFIX)(Reg *d, Reg *s, int order)
@@ -547,7 +549,7 @@ void glue(helper_pshufd, SUFFIX)(Reg *d, Reg *s, int order)
r.L(1) = s->L((order >> 2) & 3);
r.L(2) = s->L((order >> 4) & 3);
r.L(3) = s->L((order >> 6) & 3);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_pshuflw, SUFFIX)(Reg *d, Reg *s, int order)
@@ -559,7 +561,7 @@ void glue(helper_pshuflw, SUFFIX)(Reg *d, Reg *s, int order)
r.W(2) = s->W((order >> 4) & 3);
r.W(3) = s->W((order >> 6) & 3);
r.Q(1) = s->Q(1);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_pshufhw, SUFFIX)(Reg *d, Reg *s, int order)
@@ -571,7 +573,7 @@ void glue(helper_pshufhw, SUFFIX)(Reg *d, Reg *s, int order)
r.W(5) = s->W(4 + ((order >> 2) & 3));
r.W(6) = s->W(4 + ((order >> 4) & 3));
r.W(7) = s->W(4 + ((order >> 6) & 3));
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
#endif
@@ -937,7 +939,7 @@ void helper_haddps(CPUX86State *env, ZMMReg *d, ZMMReg *s)
r.ZMM_S(1) = float32_add(d->ZMM_S(2), d->ZMM_S(3), &env->sse_status);
r.ZMM_S(2) = float32_add(s->ZMM_S(0), s->ZMM_S(1), &env->sse_status);
r.ZMM_S(3) = float32_add(s->ZMM_S(2), s->ZMM_S(3), &env->sse_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_haddpd(CPUX86State *env, ZMMReg *d, ZMMReg *s)
@@ -946,7 +948,7 @@ void helper_haddpd(CPUX86State *env, ZMMReg *d, ZMMReg *s)
r.ZMM_D(0) = float64_add(d->ZMM_D(0), d->ZMM_D(1), &env->sse_status);
r.ZMM_D(1) = float64_add(s->ZMM_D(0), s->ZMM_D(1), &env->sse_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_hsubps(CPUX86State *env, ZMMReg *d, ZMMReg *s)
@@ -957,7 +959,7 @@ void helper_hsubps(CPUX86State *env, ZMMReg *d, ZMMReg *s)
r.ZMM_S(1) = float32_sub(d->ZMM_S(2), d->ZMM_S(3), &env->sse_status);
r.ZMM_S(2) = float32_sub(s->ZMM_S(0), s->ZMM_S(1), &env->sse_status);
r.ZMM_S(3) = float32_sub(s->ZMM_S(2), s->ZMM_S(3), &env->sse_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_hsubpd(CPUX86State *env, ZMMReg *d, ZMMReg *s)
@@ -966,7 +968,7 @@ void helper_hsubpd(CPUX86State *env, ZMMReg *d, ZMMReg *s)
r.ZMM_D(0) = float64_sub(d->ZMM_D(0), d->ZMM_D(1), &env->sse_status);
r.ZMM_D(1) = float64_sub(s->ZMM_D(0), s->ZMM_D(1), &env->sse_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_addsubps(CPUX86State *env, ZMMReg *d, ZMMReg *s)
@@ -1153,7 +1155,7 @@ void glue(helper_packsswb, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.B(14) = satsb((int16_t)s->W(6));
r.B(15) = satsb((int16_t)s->W(7));
#endif
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_packuswb, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -1180,7 +1182,7 @@ void glue(helper_packuswb, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.B(14) = satub((int16_t)s->W(6));
r.B(15) = satub((int16_t)s->W(7));
#endif
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_packssdw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -1199,7 +1201,7 @@ void glue(helper_packssdw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.W(6) = satsw(s->L(2));
r.W(7) = satsw(s->L(3));
#endif
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
#define UNPCK_OP(base_name, base) \
@@ -1226,8 +1228,8 @@ void glue(helper_packssdw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.B(13) = s->B((base << (SHIFT + 2)) + 6); \
r.B(14) = d->B((base << (SHIFT + 2)) + 7); \
r.B(15) = s->B((base << (SHIFT + 2)) + 7); \
- ) \
- *d = r; \
+ ) \
+ memcpy(d, &r, REG_WIDTH); \
} \
\
void glue(helper_punpck ## base_name ## wd, SUFFIX)(CPUX86State *env,\
@@ -1245,7 +1247,7 @@ void glue(helper_packssdw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.W(6) = d->W((base << (SHIFT + 1)) + 3); \
r.W(7) = s->W((base << (SHIFT + 1)) + 3); \
) \
- *d = r; \
+ memcpy(d, &r, REG_WIDTH); \
} \
\
void glue(helper_punpck ## base_name ## dq, SUFFIX)(CPUX86State *env,\
@@ -1259,7 +1261,7 @@ void glue(helper_packssdw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.L(2) = d->L((base << SHIFT) + 1); \
r.L(3) = s->L((base << SHIFT) + 1); \
) \
- *d = r; \
+ memcpy(d, &r, REG_WIDTH); \
} \
\
XMM_ONLY( \
@@ -1272,7 +1274,7 @@ void glue(helper_packssdw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
\
r.Q(0) = d->Q(base); \
r.Q(1) = s->Q(base); \
- *d = r; \
+ memcpy(d, &r, REG_WIDTH); \
} \
)
@@ -1313,7 +1315,7 @@ void helper_pfacc(CPUX86State *env, MMXReg *d, MMXReg *s)
r.MMX_S(0) = float32_add(d->MMX_S(0), d->MMX_S(1), &env->mmx_status);
r.MMX_S(1) = float32_add(s->MMX_S(0), s->MMX_S(1), &env->mmx_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_pfadd(CPUX86State *env, MMXReg *d, MMXReg *s)
@@ -1378,7 +1380,7 @@ void helper_pfnacc(CPUX86State *env, MMXReg *d, MMXReg *s)
r.MMX_S(0) = float32_sub(d->MMX_S(0), d->MMX_S(1), &env->mmx_status);
r.MMX_S(1) = float32_sub(s->MMX_S(0), s->MMX_S(1), &env->mmx_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_pfpnacc(CPUX86State *env, MMXReg *d, MMXReg *s)
@@ -1387,7 +1389,7 @@ void helper_pfpnacc(CPUX86State *env, MMXReg *d, MMXReg
*s)
r.MMX_S(0) = float32_sub(d->MMX_S(0), d->MMX_S(1), &env->mmx_status);
r.MMX_S(1) = float32_add(s->MMX_S(0), s->MMX_S(1), &env->mmx_status);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void helper_pfrcp(CPUX86State *env, MMXReg *d, MMXReg *s)
@@ -1424,21 +1426,27 @@ void helper_pswapd(CPUX86State *env, MMXReg *d, MMXReg
*s)
r.MMX_L(0) = s->MMX_L(1);
r.MMX_L(1) = s->MMX_L(0);
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
#endif
/* SSSE3 op helpers */
void glue(helper_pshufb, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
{
+ const uint8_t scm_mask = REG_WIDTH - 1;
int i;
Reg r;
- for (i = 0; i < (8 << SHIFT); i++) {
- r.B(i) = (s->B(i) & 0x80) ? 0 : (d->B(s->B(i) & ((8 << SHIFT) - 1)));
+ for (i = 0; i < REG_WIDTH; i++) {
+ uint8_t scm = s->B(i); /* shuffle control mask */
+ if (scm & 0x80) {
+ r.B(i) = 0;
+ } else {
+ r.B(i) = d->B(scm & scm_mask);
+ }
}
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_phaddw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -1455,7 +1463,7 @@ void glue(helper_phaddw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
XMM_ONLY(r.W(6) = (int16_t)s->W(4) + (int16_t)s->W(5));
XMM_ONLY(r.W(7) = (int16_t)s->W(6) + (int16_t)s->W(7));
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_phaddd, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -1467,7 +1475,7 @@ void glue(helper_phaddd, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.L((1 << SHIFT) + 0) = (int32_t)s->L(0) + (int32_t)s->L(1);
XMM_ONLY(r.L(3) = (int32_t)s->L(2) + (int32_t)s->L(3));
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_phaddsw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -1483,7 +1491,7 @@ void glue(helper_phaddsw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
XMM_ONLY(r.W(6) = satsw((int16_t)s->W(4) + (int16_t)s->W(5)));
XMM_ONLY(r.W(7) = satsw((int16_t)s->W(6) + (int16_t)s->W(7)));
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
void glue(helper_pmaddubsw, SUFFIX)(CPUX86State *env, Reg *d, Reg *s)
@@ -1585,7 +1593,7 @@ void glue(helper_palignr, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s,
#undef SHR
}
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
#define XMM0 (env->xmm_regs[0])
@@ -1718,7 +1726,7 @@ void glue(helper_packusdw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s)
r.W(5) = satuw((int32_t) s->L(1));
r.W(6) = satuw((int32_t) s->L(2));
r.W(7) = satuw((int32_t) s->L(3));
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
#define FMINSB(d, s) MIN((int8_t)d, (int8_t)s)
@@ -1984,7 +1992,7 @@ void glue(helper_mpsadbw, SUFFIX)(CPUX86State *env, Reg
*d, Reg *s,
r.W(i) += abs1(d->B(d0 + 3) - s->B(s0 + 3));
}
- *d = r;
+ memcpy(d, &r, REG_WIDTH);
}
/* SSE4.2 op helpers */
@@ -2324,3 +2332,4 @@ void glue(helper_aeskeygenassist, SUFFIX)(CPUX86State
*env, Reg *d, Reg *s,
#undef L
#undef Q
#undef SUFFIX
+#undef REG_WIDTH
--
2.30.2
- [RFC PATCH] target/i386: avoid copying junk to extended ZMMReg fields,
Alex Bennée <=