* [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
@ 2020-08-12 14:39 ` Jean-Philippe Brucker
0 siblings, 0 replies; 6+ messages in thread
From: Jean-Philippe Brucker @ 2020-08-12 14:39 UTC (permalink / raw)
To: ast, daniel
Cc: kafai, songliubraving, yhs, andriin, john.fastabend, kpsingh,
bpf, linux-arm-kernel, Jean-Philippe Brucker, Jakov Petrina
When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
DWARF information using a base type "__Poly8_t", which is internal to
GCC and not recognized by Clang. This causes build failures when
building with Clang a vmlinux.h generated from an arm64 kernel that was
built with GCC.
vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
typedef __Poly8_t poly8x16_t[16];
^~~~~~~~~
The polyX_t types are defined as unsigned integers in the "Arm C
Language Extension" document (101028_Q220_00_en). Emit typedefs based on
standard integer types for the GCC internal types, similar to those
emitted by Clang.
Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
max(), causing a build bug due to different types, hence the seemingly
unrelated change.
Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
v2:
* Tried to clarify the commit message a bit.
* Made __Poly64_t an unsigned long long, for portability.
* Improve names.
---
tools/lib/bpf/btf_dump.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index cf711168d34a..ac81f3f8957a 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -13,6 +13,7 @@
#include <errno.h>
#include <linux/err.h>
#include <linux/btf.h>
+#include <linux/kernel.h>
#include "btf.h"
#include "hashmap.h"
#include "libbpf.h"
@@ -549,6 +550,9 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
}
}
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+ const struct btf_type *t);
+
static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
const struct btf_type *t);
static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id,
@@ -671,6 +675,9 @@ static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
switch (kind) {
case BTF_KIND_INT:
+ /* Emit type alias definitions if necessary */
+ btf_dump_emit_missing_aliases(d, id, t);
+
tstate->emit_state = EMITTED;
break;
case BTF_KIND_ENUM:
@@ -870,7 +877,7 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
btf_dump_printf(d, ": %d", m_sz);
off = m_off + m_sz;
} else {
- m_sz = max(0, btf__resolve_size(d->btf, m->type));
+ m_sz = max(0LL, btf__resolve_size(d->btf, m->type));
off = m_off + m_sz * 8;
}
btf_dump_printf(d, ";");
@@ -890,6 +897,32 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
btf_dump_printf(d, " __attribute__((packed))");
}
+static const char *missing_base_types[][2] = {
+ /*
+ * GCC emits typedefs to its internal __PolyX_t types when compiling Arm
+ * SIMD intrinsics. Alias them to standard base types.
+ */
+ { "__Poly8_t", "unsigned char" },
+ { "__Poly16_t", "unsigned short" },
+ { "__Poly64_t", "unsigned long long" },
+ { "__Poly128_t", "unsigned __int128" },
+};
+
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+ const struct btf_type *t)
+{
+ const char *name = btf_dump_type_name(d, id);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) {
+ if (strcmp(name, missing_base_types[i][0]) == 0) {
+ btf_dump_printf(d, "typedef %s %s;\n\n",
+ missing_base_types[i][1], name);
+ break;
+ }
+ }
+}
+
static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
const struct btf_type *t)
{
--
2.27.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
@ 2020-08-12 14:39 ` Jean-Philippe Brucker
0 siblings, 0 replies; 6+ messages in thread
From: Jean-Philippe Brucker @ 2020-08-12 14:39 UTC (permalink / raw)
To: ast, daniel
Cc: Jean-Philippe Brucker, songliubraving, Jakov Petrina,
john.fastabend, kpsingh, yhs, bpf, andriin, kafai,
linux-arm-kernel
When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
DWARF information using a base type "__Poly8_t", which is internal to
GCC and not recognized by Clang. This causes build failures when
building with Clang a vmlinux.h generated from an arm64 kernel that was
built with GCC.
vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
typedef __Poly8_t poly8x16_t[16];
^~~~~~~~~
The polyX_t types are defined as unsigned integers in the "Arm C
Language Extension" document (101028_Q220_00_en). Emit typedefs based on
standard integer types for the GCC internal types, similar to those
emitted by Clang.
Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
max(), causing a build bug due to different types, hence the seemingly
unrelated change.
Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
v2:
* Tried to clarify the commit message a bit.
* Made __Poly64_t an unsigned long long, for portability.
* Improve names.
---
tools/lib/bpf/btf_dump.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index cf711168d34a..ac81f3f8957a 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -13,6 +13,7 @@
#include <errno.h>
#include <linux/err.h>
#include <linux/btf.h>
+#include <linux/kernel.h>
#include "btf.h"
#include "hashmap.h"
#include "libbpf.h"
@@ -549,6 +550,9 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr)
}
}
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+ const struct btf_type *t);
+
static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
const struct btf_type *t);
static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id,
@@ -671,6 +675,9 @@ static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
switch (kind) {
case BTF_KIND_INT:
+ /* Emit type alias definitions if necessary */
+ btf_dump_emit_missing_aliases(d, id, t);
+
tstate->emit_state = EMITTED;
break;
case BTF_KIND_ENUM:
@@ -870,7 +877,7 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
btf_dump_printf(d, ": %d", m_sz);
off = m_off + m_sz;
} else {
- m_sz = max(0, btf__resolve_size(d->btf, m->type));
+ m_sz = max(0LL, btf__resolve_size(d->btf, m->type));
off = m_off + m_sz * 8;
}
btf_dump_printf(d, ";");
@@ -890,6 +897,32 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
btf_dump_printf(d, " __attribute__((packed))");
}
+static const char *missing_base_types[][2] = {
+ /*
+ * GCC emits typedefs to its internal __PolyX_t types when compiling Arm
+ * SIMD intrinsics. Alias them to standard base types.
+ */
+ { "__Poly8_t", "unsigned char" },
+ { "__Poly16_t", "unsigned short" },
+ { "__Poly64_t", "unsigned long long" },
+ { "__Poly128_t", "unsigned __int128" },
+};
+
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id,
+ const struct btf_type *t)
+{
+ const char *name = btf_dump_type_name(d, id);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) {
+ if (strcmp(name, missing_base_types[i][0]) == 0) {
+ btf_dump_printf(d, "typedef %s %s;\n\n",
+ missing_base_types[i][1], name);
+ break;
+ }
+ }
+}
+
static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id,
const struct btf_type *t)
{
--
2.27.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
2020-08-12 14:39 ` Jean-Philippe Brucker
@ 2020-08-12 17:35 ` Andrii Nakryiko
-1 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2020-08-12 17:35 UTC (permalink / raw)
To: Jean-Philippe Brucker
Cc: Alexei Starovoitov, Daniel Borkmann, Martin Lau, Song Liu,
Yonghong Song, Andrii Nakryiko, john fastabend, KP Singh, bpf,
linux-arm-kernel, Jakov Petrina
On Wed, Aug 12, 2020 at 7:42 AM Jean-Philippe Brucker
<jean-philippe@linaro.org> wrote:
>
> When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
> DWARF information using a base type "__Poly8_t", which is internal to
> GCC and not recognized by Clang. This causes build failures when
> building with Clang a vmlinux.h generated from an arm64 kernel that was
> built with GCC.
>
> vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
> typedef __Poly8_t poly8x16_t[16];
> ^~~~~~~~~
>
> The polyX_t types are defined as unsigned integers in the "Arm C
> Language Extension" document (101028_Q220_00_en). Emit typedefs based on
> standard integer types for the GCC internal types, similar to those
> emitted by Clang.
>
> Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
> max(), causing a build bug due to different types, hence the seemingly
> unrelated change.
>
> Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
LGTM.
Acked-by: Andrii Nakryiko <andriin@fb.com>
[...]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
@ 2020-08-12 17:35 ` Andrii Nakryiko
0 siblings, 0 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2020-08-12 17:35 UTC (permalink / raw)
To: Jean-Philippe Brucker
Cc: Song Liu, Daniel Borkmann, Jakov Petrina, john fastabend,
Alexei Starovoitov, KP Singh, Yonghong Song, bpf,
Andrii Nakryiko, Martin Lau, linux-arm-kernel
On Wed, Aug 12, 2020 at 7:42 AM Jean-Philippe Brucker
<jean-philippe@linaro.org> wrote:
>
> When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
> DWARF information using a base type "__Poly8_t", which is internal to
> GCC and not recognized by Clang. This causes build failures when
> building with Clang a vmlinux.h generated from an arm64 kernel that was
> built with GCC.
>
> vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
> typedef __Poly8_t poly8x16_t[16];
> ^~~~~~~~~
>
> The polyX_t types are defined as unsigned integers in the "Arm C
> Language Extension" document (101028_Q220_00_en). Emit typedefs based on
> standard integer types for the GCC internal types, similar to those
> emitted by Clang.
>
> Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
> max(), causing a build bug due to different types, hence the seemingly
> unrelated change.
>
> Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
LGTM.
Acked-by: Andrii Nakryiko <andriin@fb.com>
[...]
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
2020-08-12 17:35 ` Andrii Nakryiko
@ 2020-08-13 1:12 ` Alexei Starovoitov
-1 siblings, 0 replies; 6+ messages in thread
From: Alexei Starovoitov @ 2020-08-13 1:12 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Jean-Philippe Brucker, Alexei Starovoitov, Daniel Borkmann,
Martin Lau, Song Liu, Yonghong Song, Andrii Nakryiko,
john fastabend, KP Singh, bpf, linux-arm-kernel, Jakov Petrina
On Wed, Aug 12, 2020 at 10:35 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Aug 12, 2020 at 7:42 AM Jean-Philippe Brucker
> <jean-philippe@linaro.org> wrote:
> >
> > When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
> > DWARF information using a base type "__Poly8_t", which is internal to
> > GCC and not recognized by Clang. This causes build failures when
> > building with Clang a vmlinux.h generated from an arm64 kernel that was
> > built with GCC.
> >
> > vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
> > typedef __Poly8_t poly8x16_t[16];
> > ^~~~~~~~~
> >
> > The polyX_t types are defined as unsigned integers in the "Arm C
> > Language Extension" document (101028_Q220_00_en). Emit typedefs based on
> > standard integer types for the GCC internal types, similar to those
> > emitted by Clang.
> >
> > Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
> > max(), causing a build bug due to different types, hence the seemingly
> > unrelated change.
> >
> > Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
>
> LGTM.
>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
Applied. Thanks
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
@ 2020-08-13 1:12 ` Alexei Starovoitov
0 siblings, 0 replies; 6+ messages in thread
From: Alexei Starovoitov @ 2020-08-13 1:12 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Jean-Philippe Brucker, Song Liu, Daniel Borkmann, Jakov Petrina,
john fastabend, Alexei Starovoitov, KP Singh, Yonghong Song, bpf,
Andrii Nakryiko, Martin Lau, linux-arm-kernel
On Wed, Aug 12, 2020 at 10:35 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Aug 12, 2020 at 7:42 AM Jean-Philippe Brucker
> <jean-philippe@linaro.org> wrote:
> >
> > When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
> > DWARF information using a base type "__Poly8_t", which is internal to
> > GCC and not recognized by Clang. This causes build failures when
> > building with Clang a vmlinux.h generated from an arm64 kernel that was
> > built with GCC.
> >
> > vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
> > typedef __Poly8_t poly8x16_t[16];
> > ^~~~~~~~~
> >
> > The polyX_t types are defined as unsigned integers in the "Arm C
> > Language Extension" document (101028_Q220_00_en). Emit typedefs based on
> > standard integer types for the GCC internal types, similar to those
> > emitted by Clang.
> >
> > Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
> > max(), causing a build bug due to different types, hence the seemingly
> > unrelated change.
> >
> > Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
>
> LGTM.
>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
Applied. Thanks
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-08-13 1:15 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2020-08-12 14:39 [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON Jean-Philippe Brucker
2020-08-12 14:39 ` Jean-Philippe Brucker
2020-08-12 17:35 ` Andrii Nakryiko
2020-08-12 17:35 ` Andrii Nakryiko
2020-08-13 1:12 ` Alexei Starovoitov
2020-08-13 1:12 ` Alexei Starovoitov
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