* [PATCH v2 1/2] include/qemu/int128.h: define struct Int128 according to the host endianness
2021-08-26 14:14 [PATCH v2 0/2] target/ppc: Fix vextu[bhw][lr]x on big endian hosts matheus.ferst
@ 2021-08-26 14:14 ` matheus.ferst
2021-08-26 14:14 ` [PATCH v2 2/2] target/ppc: fix vextu[bhw][lr]x helpers matheus.ferst
2021-08-27 2:42 ` [PATCH v2 0/2] target/ppc: Fix vextu[bhw][lr]x on big endian hosts David Gibson
2 siblings, 0 replies; 4+ messages in thread
From: matheus.ferst @ 2021-08-26 14:14 UTC (permalink / raw)
To: qemu-devel, qemu-ppc
Cc: peter.maydell, richard.henderson, f4bug, groug, Matheus Ferst,
david
From: Matheus Ferst <matheus.ferst@eldorado.org.br>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
---
include/qemu/int128.h | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/include/qemu/int128.h b/include/qemu/int128.h
index 64500385e3..17436d851d 100644
--- a/include/qemu/int128.h
+++ b/include/qemu/int128.h
@@ -162,24 +162,37 @@ static inline Int128 bswap128(Int128 a)
typedef struct Int128 Int128;
+/*
+ * We guarantee that the in-memory byte representation of an
+ * Int128 is that of a host-endian-order 128-bit integer
+ * (whether using this struct or the __int128_t version of the type).
+ * Some code using this type relies on this (eg when copying it into
+ * guest memory or a gdb protocol buffer, or by using Int128 in
+ * a union with other integer types).
+ */
struct Int128 {
+#ifdef HOST_WORDS_BIGENDIAN
+ int64_t hi;
+ uint64_t lo;
+#else
uint64_t lo;
int64_t hi;
+#endif
};
static inline Int128 int128_make64(uint64_t a)
{
- return (Int128) { a, 0 };
+ return (Int128) { .lo = a, .hi = 0 };
}
static inline Int128 int128_makes64(int64_t a)
{
- return (Int128) { a, a >> 63 };
+ return (Int128) { .lo = a, .hi = a >> 63 };
}
static inline Int128 int128_make128(uint64_t lo, uint64_t hi)
{
- return (Int128) { lo, hi };
+ return (Int128) { .lo = lo, .hi = hi };
}
static inline uint64_t int128_get64(Int128 a)
@@ -210,22 +223,22 @@ static inline Int128 int128_one(void)
static inline Int128 int128_2_64(void)
{
- return (Int128) { 0, 1 };
+ return int128_make128(0, 1);
}
static inline Int128 int128_exts64(int64_t a)
{
- return (Int128) { .lo = a, .hi = (a < 0) ? -1 : 0 };
+ return int128_make128(a, (a < 0) ? -1 : 0);
}
static inline Int128 int128_and(Int128 a, Int128 b)
{
- return (Int128) { a.lo & b.lo, a.hi & b.hi };
+ return int128_make128(a.lo & b.lo, a.hi & b.hi);
}
static inline Int128 int128_or(Int128 a, Int128 b)
{
- return (Int128) { a.lo | b.lo, a.hi | b.hi };
+ return int128_make128(a.lo | b.lo, a.hi | b.hi);
}
static inline Int128 int128_rshift(Int128 a, int n)
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 2/2] target/ppc: fix vextu[bhw][lr]x helpers
2021-08-26 14:14 [PATCH v2 0/2] target/ppc: Fix vextu[bhw][lr]x on big endian hosts matheus.ferst
2021-08-26 14:14 ` [PATCH v2 1/2] include/qemu/int128.h: define struct Int128 according to the host endianness matheus.ferst
@ 2021-08-26 14:14 ` matheus.ferst
2021-08-27 2:42 ` [PATCH v2 0/2] target/ppc: Fix vextu[bhw][lr]x on big endian hosts David Gibson
2 siblings, 0 replies; 4+ messages in thread
From: matheus.ferst @ 2021-08-26 14:14 UTC (permalink / raw)
To: qemu-devel, qemu-ppc
Cc: peter.maydell, richard.henderson, f4bug, groug, Matheus Ferst,
david
From: Matheus Ferst <matheus.ferst@eldorado.org.br>
These helpers shouldn't depend on the host endianness, as they only use
shifts, ands, and int128_* methods.
Fixes: 60caf2216bf0 ("target-ppc: add vextu[bhw][lr]x instructions")
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
---
target/ppc/int_helper.c | 38 ++++++++++----------------------------
1 file changed, 10 insertions(+), 28 deletions(-)
diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c
index efa833ef64..c2d3248d1e 100644
--- a/target/ppc/int_helper.c
+++ b/target/ppc/int_helper.c
@@ -1492,34 +1492,16 @@ void helper_vlogefp(CPUPPCState *env, ppc_avr_t *r, ppc_avr_t *b)
}
}
-#if defined(HOST_WORDS_BIGENDIAN)
-#define VEXTU_X_DO(name, size, left) \
- target_ulong glue(helper_, name)(target_ulong a, ppc_avr_t *b) \
- { \
- int index; \
- if (left) { \
- index = (a & 0xf) * 8; \
- } else { \
- index = ((15 - (a & 0xf) + 1) * 8) - size; \
- } \
- return int128_getlo(int128_rshift(b->s128, index)) & \
- MAKE_64BIT_MASK(0, size); \
- }
-#else
-#define VEXTU_X_DO(name, size, left) \
- target_ulong glue(helper_, name)(target_ulong a, ppc_avr_t *b) \
- { \
- int index; \
- if (left) { \
- index = ((15 - (a & 0xf) + 1) * 8) - size; \
- } else { \
- index = (a & 0xf) * 8; \
- } \
- return int128_getlo(int128_rshift(b->s128, index)) & \
- MAKE_64BIT_MASK(0, size); \
- }
-#endif
-
+#define VEXTU_X_DO(name, size, left) \
+target_ulong glue(helper_, name)(target_ulong a, ppc_avr_t *b) \
+{ \
+ int index = (a & 0xf) * 8; \
+ if (left) { \
+ index = 128 - index - size; \
+ } \
+ return int128_getlo(int128_rshift(b->s128, index)) & \
+ MAKE_64BIT_MASK(0, size); \
+}
VEXTU_X_DO(vextublx, 8, 1)
VEXTU_X_DO(vextuhlx, 16, 1)
VEXTU_X_DO(vextuwlx, 32, 1)
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2 0/2] target/ppc: Fix vextu[bhw][lr]x on big endian hosts
2021-08-26 14:14 [PATCH v2 0/2] target/ppc: Fix vextu[bhw][lr]x on big endian hosts matheus.ferst
2021-08-26 14:14 ` [PATCH v2 1/2] include/qemu/int128.h: define struct Int128 according to the host endianness matheus.ferst
2021-08-26 14:14 ` [PATCH v2 2/2] target/ppc: fix vextu[bhw][lr]x helpers matheus.ferst
@ 2021-08-27 2:42 ` David Gibson
2 siblings, 0 replies; 4+ messages in thread
From: David Gibson @ 2021-08-27 2:42 UTC (permalink / raw)
To: matheus.ferst
Cc: peter.maydell, richard.henderson, f4bug, qemu-devel, groug,
qemu-ppc
[-- Attachment #1: Type: text/plain, Size: 1404 bytes --]
On Thu, Aug 26, 2021 at 11:14:44AM -0300, matheus.ferst@eldorado.org.br wrote:
> From: Matheus Ferst <matheus.ferst@eldorado.org.br>
>
> The definition of struct Int128 is currently independent of the host
> endianness, causing different results when using the member s128 of
> union ppc_vsr_t in big-endian builds with CONFIG_INT128 or
> !CONFIG_INT128.
>
> The only PPC instructions that seem to be affected by this issue are the
> "Vector Extract Unsigned Byte/Halfword/Word to GPR using GPR-specified
> Left/Right-Index." Even on builds with Int128 support, however, their
> helpers give the wrong result on big-endian hosts.
>
> The first patch in this series changes the definition of struct Int128
> to allow its use in the ppc_vsr_t union. The second patch fixes the
> helper definition.
Applied to ppc-for-6.2, thanks.
>
> Matheus Ferst (2):
> include/qemu/int128.h: define struct Int128 according to the host
> endianness
> target/ppc: fix vextu[bhw][lr]x helpers
>
> include/qemu/int128.h | 27 ++++++++++++++++++++-------
> target/ppc/int_helper.c | 38 ++++++++++----------------------------
> 2 files changed, 30 insertions(+), 35 deletions(-)
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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^ permalink raw reply [flat|nested] 4+ messages in thread