This consumes functionality exported in the previous patch. It does the
main job of printing with BTF data. This is used in the following patch
to provide a more readable output of a map's dump. It relies on
json_writer to do json printing. Below is sample output where map keys
are ints and values are of type struct A:
typedef int int_type;
enum E {
E0,
E1,
};
struct B {
int x;
int y;
};
struct A {
int m;
unsigned long long n;
char o;
int p[8];
int q[4][8];
enum E r;
void *s;
struct B t;
const int u;
int_type v;
unsigned int w1: 3;
unsigned int w2: 3;
};
$ sudo bpftool map dump id 14
[{
"key": 0,
"value": {
"m": 1,
"n": 2,
"o": "c",
"p": [15,16,17,18,15,16,17,18
],
"q": [[25,26,27,28,25,26,27,28
],[35,36,37,38,35,36,37,38
],[45,46,47,48,45,46,47,48
],[55,56,57,58,55,56,57,58
]
],
"r": 1,
"s": 0x7ffd80531cf8,
"t": {
"x": 5,
"y": 10
},
"u": 100,
"v": 20,
"w1": 0x7,
"w2": 0x3
}
}
]
This patch uses json's {} and [] to imply struct/union and array. More
explicit information can be added later. For example, a command line
option can be introduced to print whether a key or value is struct
or union, name of a struct etc. This will however come at the expense
of duplicating info when, for example, printing an array of structs.
enums are printed as ints without their names.
Signed-off-by: Okash Khawaja <[email protected]>
---
tools/bpf/bpftool/btf_dumper.c | 248 +++++++++++++++++++++++++++++++++++++++++
tools/bpf/bpftool/main.h | 15 ++
2 files changed, 263 insertions(+)
--- /dev/null
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018 Facebook */
+
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <stdio.h> /* for (FILE *) used by json_writer */
+#include <linux/bitops.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "btf.h"
+#include "json_writer.h"
+#include "main.h"
+
+#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
+#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
+#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
+#define BITS_ROUNDUP_BYTES(bits) \
+ (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
+
+static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
+ __u8 bit_offset, const void *data);
+
+static void btf_dumper_ptr(const void *data, json_writer_t *jw,
+ bool is_plain_text)
+{
+ if (is_plain_text)
+ jsonw_printf(jw, "%p", *((unsigned long *)data));
+ else
+ jsonw_printf(jw, "%u", *((unsigned long *)data));
+}
+
+static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
+ const void *data)
+{
+ int actual_type_id;
+
+ actual_type_id = btf__resolve_type(d->btf, type_id);
+ if (actual_type_id < 0)
+ return actual_type_id;
+
+ return btf_dumper_do_type(d, actual_type_id, 0, data);
+}
+
+static void btf_dumper_enum(const void *data, json_writer_t *jw)
+{
+ jsonw_printf(jw, "%d", *(int *)data);
+}
+
+static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
+ const void *data)
+{
+ const struct btf_type *t = btf__type_by_id(d->btf, type_id);
+ struct btf_array *arr = (struct btf_array *)(t + 1);
+ long long elem_size;
+ int ret = 0;
+ __u32 i;
+
+ elem_size = btf__resolve_size(d->btf, arr->type);
+ if (elem_size < 0)
+ return elem_size;
+
+ jsonw_start_array(d->jw);
+ for (i = 0; i < arr->nelems; i++) {
+ ret = btf_dumper_do_type(d, arr->type, 0,
+ data + i * elem_size);
+ if (ret)
+ break;
+ }
+
+ jsonw_end_array(d->jw);
+ return ret;
+}
+
+static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
+ const void *data, json_writer_t *jw,
+ bool is_plain_text)
+{
+ int left_shift_bits, right_shift_bits;
+ int nr_bits = BTF_INT_BITS(int_type);
+ int total_bits_offset;
+ int bytes_to_copy;
+ int bits_to_copy;
+ __u64 print_num;
+
+ total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
+ data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
+ bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
+ bits_to_copy = bit_offset + nr_bits;
+ bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
+
+ print_num = 0;
+ memcpy(&print_num, data, bytes_to_copy);
+#ifdef __BIG_ENDIAN_BITFIELD
+ left_shift_bits = bit_offset;
+#else
+ left_shift_bits = 64 - bits_to_copy;
+#endif
+ right_shift_bits = 64 - nr_bits;
+
+ print_num <<= left_shift_bits;
+ print_num >>= right_shift_bits;
+ if (is_plain_text)
+ jsonw_printf(jw, "0x%llx", print_num);
+ else
+ jsonw_printf(jw, "%llu", print_num);
+}
+
+static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
+ const void *data, json_writer_t *jw,
+ bool is_plain_text)
+{
+ __u32 *int_type;
+ __u32 nr_bits;
+
+ int_type = (__u32 *)(t + 1);
+ nr_bits = BTF_INT_BITS(*int_type);
+ /* if this is bit field */
+ if (bit_offset || BTF_INT_OFFSET(*int_type) ||
+ BITS_PER_BYTE_MASKED(nr_bits)) {
+ btf_dumper_int_bits(*int_type, bit_offset, data, jw,
+ is_plain_text);
+ return 0;
+ }
+
+ switch (BTF_INT_ENCODING(*int_type)) {
+ case 0:
+ if (BTF_INT_BITS(*int_type) == 64)
+ jsonw_printf(jw, "%lu", *(__u64 *)data);
+ else if (BTF_INT_BITS(*int_type) == 32)
+ jsonw_printf(jw, "%u", *(__u32 *)data);
+ else if (BTF_INT_BITS(*int_type) == 16)
+ jsonw_printf(jw, "%hu", *(__u16 *)data);
+ else if (BTF_INT_BITS(*int_type) == 8)
+ jsonw_printf(jw, "%hhu", *(__u8 *)data);
+ else
+ btf_dumper_int_bits(*int_type, bit_offset, data, jw,
+ is_plain_text);
+ break;
+ case BTF_INT_SIGNED:
+ if (BTF_INT_BITS(*int_type) == 64)
+ jsonw_printf(jw, "%ld", *(long long *)data);
+ else if (BTF_INT_BITS(*int_type) == 32)
+ jsonw_printf(jw, "%d", *(int *)data);
+ else if (BTF_INT_BITS(*int_type) == 16)
+ jsonw_printf(jw, "%hd", *(short *)data);
+ else if (BTF_INT_BITS(*int_type) == 8)
+ jsonw_printf(jw, "%hhd", *(char *)data);
+ else
+ btf_dumper_int_bits(*int_type, bit_offset, data, jw,
+ is_plain_text);
+ break;
+ case BTF_INT_CHAR:
+ if (isprint(*(char *)data))
+ jsonw_printf(jw, "\"%c\"", *(char *)data);
+ else
+ if (is_plain_text)
+ jsonw_printf(jw, "0x%hhx", *(char *)data);
+ else
+ jsonw_printf(jw, "\"\\u00%02hhx\"",
+ *(char *)data);
+ break;
+ case BTF_INT_BOOL:
+ jsonw_bool(jw, *(int *)data);
+ break;
+ default:
+ /* shouldn't happen */
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
+ const void *data)
+{
+ const struct btf_type *t;
+ struct btf_member *m;
+ const void *data_off;
+ int ret = 0;
+ int i, vlen;
+
+ t = btf__type_by_id(d->btf, type_id);
+ if (!t)
+ return -EINVAL;
+
+ vlen = BTF_INFO_VLEN(t->info);
+ jsonw_start_object(d->jw);
+ m = (struct btf_member *)(t + 1);
+
+ for (i = 0; i < vlen; i++) {
+ data_off = data + BITS_ROUNDDOWN_BYTES(m[i].offset);
+ jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
+ ret = btf_dumper_do_type(d, m[i].type,
+ BITS_PER_BYTE_MASKED(m[i].offset),
+ data_off);
+ if (ret)
+ break;
+ }
+
+ jsonw_end_object(d->jw);
+
+ return ret;
+}
+
+static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
+ __u8 bit_offset, const void *data)
+{
+ const struct btf_type *t = btf__type_by_id(d->btf, type_id);
+
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_INT:
+ return btf_dumper_int(t, bit_offset, data, d->jw,
+ d->is_plain_text);
+ case BTF_KIND_STRUCT:
+ case BTF_KIND_UNION:
+ return btf_dumper_struct(d, type_id, data);
+ case BTF_KIND_ARRAY:
+ return btf_dumper_array(d, type_id, data);
+ case BTF_KIND_ENUM:
+ btf_dumper_enum(data, d->jw);
+ return 0;
+ case BTF_KIND_PTR:
+ btf_dumper_ptr(data, d->jw, d->is_plain_text);
+ return 0;
+ case BTF_KIND_UNKN:
+ jsonw_printf(d->jw, "(unknown)");
+ return 0;
+ case BTF_KIND_FWD:
+ /* map key or value can't be forward */
+ jsonw_printf(d->jw, "(fwd-kind-invalid)");
+ return -EINVAL;
+ case BTF_KIND_TYPEDEF:
+ case BTF_KIND_VOLATILE:
+ case BTF_KIND_CONST:
+ case BTF_KIND_RESTRICT:
+ return btf_dumper_modifier(d, type_id, data);
+ default:
+ jsonw_printf(d->jw, "(unsupported-kind");
+ return -EINVAL;
+ }
+}
+
+int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
+ const void *data)
+{
+ return btf_dumper_do_type(d, type_id, 0, data);
+}
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -131,4 +131,19 @@ unsigned int get_page_size(void);
unsigned int get_possible_cpus(void);
const char *ifindex_to_bfd_name_ns(__u32 ifindex, __u64 ns_dev, __u64 ns_ino);
+struct btf_dumper {
+ const struct btf *btf;
+ json_writer_t *jw;
+ bool is_plain_text;
+};
+
+/* btf_dumper_type - print data along with type information
+ * @d: an instance containing context for dumping types
+ * @type_id: index in btf->types array. this points to the type to be dumped
+ * @data: pointer the actual data, i.e. the values to be printed
+ *
+ * Returns zero on success and negative error code otherwise
+ */
+int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
+ const void *data);
#endif
Thank you for all the changes made so far.
On Tue, 10 Jul 2018 20:21:10 -0700, Okash Khawaja wrote:
> --- /dev/null
> +++ b/tools/bpf/bpftool/btf_dumper.c
> @@ -0,0 +1,248 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2018 Facebook */
> +
> +#include <linux/btf.h>
> +#include <linux/err.h>
> +#include <stdio.h> /* for (FILE *) used by json_writer */
> +#include <linux/bitops.h>
> +#include <string.h>
> +#include <ctype.h>
Again, please sort the headers the way I suggested. Otherwise as the
list of includes grows it's hard to know what's already there.
> +#include "btf.h"
> +#include "json_writer.h"
> +#include "main.h"
> +
> +#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
> +#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
> +#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
> +#define BITS_ROUNDUP_BYTES(bits) \
> + (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
> +
> +static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
> + __u8 bit_offset, const void *data);
> +
> +static void btf_dumper_ptr(const void *data, json_writer_t *jw,
> + bool is_plain_text)
> +{
> + if (is_plain_text)
> + jsonw_printf(jw, "%p", *((unsigned long *)data));
> + else
> + jsonw_printf(jw, "%u", *((unsigned long *)data));
Again, please drop the extraneous parens.
> +}
> +
> +static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
> + const void *data, json_writer_t *jw,
> + bool is_plain_text)
> +{
> + int left_shift_bits, right_shift_bits;
> + int nr_bits = BTF_INT_BITS(int_type);
> + int total_bits_offset;
> + int bytes_to_copy;
> + int bits_to_copy;
> + __u64 print_num;
> +
> + total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
> + data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
> + bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
> + bits_to_copy = bit_offset + nr_bits;
> + bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
> +
> + print_num = 0;
> + memcpy(&print_num, data, bytes_to_copy);
> +#ifdef __BIG_ENDIAN_BITFIELD
> + left_shift_bits = bit_offset;
> +#else
> + left_shift_bits = 64 - bits_to_copy;
> +#endif
> + right_shift_bits = 64 - nr_bits;
Please include <asm/byteorder.h> as I suggested to you previously.
This is dead code right now, look:
$ git diff
diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index c64465094b92..045add07b721 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -91,7 +91,8 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
print_num = 0;
memcpy(&print_num, data, bytes_to_copy);
-#ifdef __BIG_ENDIAN_BITFIELD
+#ifndef __LITTLE_ENDIAN_BITFIELD
+#error "abc"
left_shift_bits = bit_offset;
#else
left_shift_bits = 64 - bits_to_copy;
$ make -C tools/bpf/bpftool/ CC=gcc-8
make: Entering directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
CC btf_dumper.o
btf_dumper.c: In function ‘btf_dumper_int_bits’:
btf_dumper.c:95:2: error: #error "abc"
#error "abc"
^~~~~
Makefile:96: recipe for target 'btf_dumper.o' failed
make: *** [btf_dumper.o] Error 1
make: Leaving directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
On 07/11/2018 09:10 PM, Jakub Kicinski wrote:
> Thank you for all the changes made so far.
>
> On Tue, 10 Jul 2018 20:21:10 -0700, Okash Khawaja wrote:
>> --- /dev/null
>> +++ b/tools/bpf/bpftool/btf_dumper.c
>> @@ -0,0 +1,248 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Copyright (c) 2018 Facebook */
>> +
>> +#include <linux/btf.h>
>> +#include <linux/err.h>
>> +#include <stdio.h> /* for (FILE *) used by json_writer */
>> +#include <linux/bitops.h>
>> +#include <string.h>
>> +#include <ctype.h>
>
> Again, please sort the headers the way I suggested. Otherwise as the
> list of includes grows it's hard to know what's already there.
>
>> +#include "btf.h"
>> +#include "json_writer.h"
>> +#include "main.h"
>> +
>> +#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
>> +#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
>> +#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
>> +#define BITS_ROUNDUP_BYTES(bits) \
>> + (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
>> +
>> +static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
>> + __u8 bit_offset, const void *data);
>> +
>> +static void btf_dumper_ptr(const void *data, json_writer_t *jw,
>> + bool is_plain_text)
>> +{
>> + if (is_plain_text)
>> + jsonw_printf(jw, "%p", *((unsigned long *)data));
>> + else
>> + jsonw_printf(jw, "%u", *((unsigned long *)data));
>
> Again, please drop the extraneous parens.
>
>> +}
>> +
>
>> +static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
>> + const void *data, json_writer_t *jw,
>> + bool is_plain_text)
>> +{
>> + int left_shift_bits, right_shift_bits;
>> + int nr_bits = BTF_INT_BITS(int_type);
>> + int total_bits_offset;
>> + int bytes_to_copy;
>> + int bits_to_copy;
>> + __u64 print_num;
>> +
>> + total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
>> + data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
>> + bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
>> + bits_to_copy = bit_offset + nr_bits;
>> + bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
>> +
>> + print_num = 0;
>> + memcpy(&print_num, data, bytes_to_copy);
>> +#ifdef __BIG_ENDIAN_BITFIELD
>> + left_shift_bits = bit_offset;
>> +#else
>> + left_shift_bits = 64 - bits_to_copy;
>> +#endif
>> + right_shift_bits = 64 - nr_bits;
>
> Please include <asm/byteorder.h> as I suggested to you previously.
> This is dead code right now, look:
>
> $ git diff
> diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
> index c64465094b92..045add07b721 100644
> --- a/tools/bpf/bpftool/btf_dumper.c
> +++ b/tools/bpf/bpftool/btf_dumper.c
> @@ -91,7 +91,8 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
>
> print_num = 0;
> memcpy(&print_num, data, bytes_to_copy);
> -#ifdef __BIG_ENDIAN_BITFIELD
> +#ifndef __LITTLE_ENDIAN_BITFIELD
> +#error "abc"
> left_shift_bits = bit_offset;
> #else
> left_shift_bits = 64 - bits_to_copy;
>
> $ make -C tools/bpf/bpftool/ CC=gcc-8
> make: Entering directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
> CC btf_dumper.o
> btf_dumper.c: In function ‘btf_dumper_int_bits’:
> btf_dumper.c:95:2: error: #error "abc"
> #error "abc"
> ^~~~~
> Makefile:96: recipe for target 'btf_dumper.o' failed
> make: *** [btf_dumper.o] Error 1
> make: Leaving directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
You could also easily test this on s390x (big endian) through a LinuxONE
test instance, this is how I usually test changes related to their JIT.
Thanks,
Daniel
On Wed, Jul 11, 2018 at 12:10:15PM -0700, Jakub Kicinski wrote:
> Thank you for all the changes made so far.
>
> On Tue, 10 Jul 2018 20:21:10 -0700, Okash Khawaja wrote:
> > --- /dev/null
> > +++ b/tools/bpf/bpftool/btf_dumper.c
> > @@ -0,0 +1,248 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright (c) 2018 Facebook */
> > +
> > +#include <linux/btf.h>
> > +#include <linux/err.h>
> > +#include <stdio.h> /* for (FILE *) used by json_writer */
> > +#include <linux/bitops.h>
> > +#include <string.h>
> > +#include <ctype.h>
>
> Again, please sort the headers the way I suggested. Otherwise as the
> list of includes grows it's hard to know what's already there.
>
> > +#include "btf.h"
> > +#include "json_writer.h"
> > +#include "main.h"
> > +
> > +#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
> > +#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
> > +#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
> > +#define BITS_ROUNDUP_BYTES(bits) \
> > + (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
> > +
> > +static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
> > + __u8 bit_offset, const void *data);
> > +
> > +static void btf_dumper_ptr(const void *data, json_writer_t *jw,
> > + bool is_plain_text)
> > +{
> > + if (is_plain_text)
> > + jsonw_printf(jw, "%p", *((unsigned long *)data));
> > + else
> > + jsonw_printf(jw, "%u", *((unsigned long *)data));
>
> Again, please drop the extraneous parens.
>
> > +}
> > +
>
> > +static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
> > + const void *data, json_writer_t *jw,
> > + bool is_plain_text)
> > +{
> > + int left_shift_bits, right_shift_bits;
> > + int nr_bits = BTF_INT_BITS(int_type);
> > + int total_bits_offset;
> > + int bytes_to_copy;
> > + int bits_to_copy;
> > + __u64 print_num;
> > +
> > + total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
> > + data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
> > + bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
> > + bits_to_copy = bit_offset + nr_bits;
> > + bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
> > +
> > + print_num = 0;
> > + memcpy(&print_num, data, bytes_to_copy);
> > +#ifdef __BIG_ENDIAN_BITFIELD
> > + left_shift_bits = bit_offset;
> > +#else
> > + left_shift_bits = 64 - bits_to_copy;
> > +#endif
> > + right_shift_bits = 64 - nr_bits;
>
> Please include <asm/byteorder.h> as I suggested to you previously.
> This is dead code right now, look:
Sorry, should have checked ifndef case. Will fix. Thanks.
>
> $ git diff
> diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
> index c64465094b92..045add07b721 100644
> --- a/tools/bpf/bpftool/btf_dumper.c
> +++ b/tools/bpf/bpftool/btf_dumper.c
> @@ -91,7 +91,8 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
>
> print_num = 0;
> memcpy(&print_num, data, bytes_to_copy);
> -#ifdef __BIG_ENDIAN_BITFIELD
> +#ifndef __LITTLE_ENDIAN_BITFIELD
> +#error "abc"
> left_shift_bits = bit_offset;
> #else
> left_shift_bits = 64 - bits_to_copy;
>
> $ make -C tools/bpf/bpftool/ CC=gcc-8
> make: Entering directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
> CC btf_dumper.o
> btf_dumper.c: In function ‘btf_dumper_int_bits’:
> btf_dumper.c:95:2: error: #error "abc"
> #error "abc"
> ^~~~~
> Makefile:96: recipe for target 'btf_dumper.o' failed
> make: *** [btf_dumper.o] Error 1
> make: Leaving directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
On Wed, Jul 11, 2018 at 10:08:35PM +0200, Daniel Borkmann wrote:
> On 07/11/2018 09:10 PM, Jakub Kicinski wrote:
> > Thank you for all the changes made so far.
> >
> > On Tue, 10 Jul 2018 20:21:10 -0700, Okash Khawaja wrote:
> >> --- /dev/null
> >> +++ b/tools/bpf/bpftool/btf_dumper.c
> >> @@ -0,0 +1,248 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/* Copyright (c) 2018 Facebook */
> >> +
> >> +#include <linux/btf.h>
> >> +#include <linux/err.h>
> >> +#include <stdio.h> /* for (FILE *) used by json_writer */
> >> +#include <linux/bitops.h>
> >> +#include <string.h>
> >> +#include <ctype.h>
> >
> > Again, please sort the headers the way I suggested. Otherwise as the
> > list of includes grows it's hard to know what's already there.
> >
> >> +#include "btf.h"
> >> +#include "json_writer.h"
> >> +#include "main.h"
> >> +
> >> +#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
> >> +#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
> >> +#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
> >> +#define BITS_ROUNDUP_BYTES(bits) \
> >> + (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
> >> +
> >> +static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
> >> + __u8 bit_offset, const void *data);
> >> +
> >> +static void btf_dumper_ptr(const void *data, json_writer_t *jw,
> >> + bool is_plain_text)
> >> +{
> >> + if (is_plain_text)
> >> + jsonw_printf(jw, "%p", *((unsigned long *)data));
> >> + else
> >> + jsonw_printf(jw, "%u", *((unsigned long *)data));
> >
> > Again, please drop the extraneous parens.
> >
> >> +}
> >> +
> >
> >> +static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
> >> + const void *data, json_writer_t *jw,
> >> + bool is_plain_text)
> >> +{
> >> + int left_shift_bits, right_shift_bits;
> >> + int nr_bits = BTF_INT_BITS(int_type);
> >> + int total_bits_offset;
> >> + int bytes_to_copy;
> >> + int bits_to_copy;
> >> + __u64 print_num;
> >> +
> >> + total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
> >> + data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
> >> + bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
> >> + bits_to_copy = bit_offset + nr_bits;
> >> + bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
> >> +
> >> + print_num = 0;
> >> + memcpy(&print_num, data, bytes_to_copy);
> >> +#ifdef __BIG_ENDIAN_BITFIELD
> >> + left_shift_bits = bit_offset;
> >> +#else
> >> + left_shift_bits = 64 - bits_to_copy;
> >> +#endif
> >> + right_shift_bits = 64 - nr_bits;
> >
> > Please include <asm/byteorder.h> as I suggested to you previously.
> > This is dead code right now, look:
> >
> > $ git diff
> > diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
> > index c64465094b92..045add07b721 100644
> > --- a/tools/bpf/bpftool/btf_dumper.c
> > +++ b/tools/bpf/bpftool/btf_dumper.c
> > @@ -91,7 +91,8 @@ static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
> >
> > print_num = 0;
> > memcpy(&print_num, data, bytes_to_copy);
> > -#ifdef __BIG_ENDIAN_BITFIELD
> > +#ifndef __LITTLE_ENDIAN_BITFIELD
> > +#error "abc"
> > left_shift_bits = bit_offset;
> > #else
> > left_shift_bits = 64 - bits_to_copy;
> >
> > $ make -C tools/bpf/bpftool/ CC=gcc-8
> > make: Entering directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
> > CC btf_dumper.o
> > btf_dumper.c: In function ‘btf_dumper_int_bits’:
> > btf_dumper.c:95:2: error: #error "abc"
> > #error "abc"
> > ^~~~~
> > Makefile:96: recipe for target 'btf_dumper.o' failed
> > make: *** [btf_dumper.o] Error 1
> > make: Leaving directory '/home/jkicinski/devel/linux/tools/bpf/bpftool'
>
> You could also easily test this on s390x (big endian) through a LinuxONE
> test instance, this is how I usually test changes related to their JIT.
Thanks. I've been using MIPS qemu set up. This will definitely help.
>
> Thanks,
> Daniel