Messages in this thread | | | Subject | Re: [PATCH bpf-next v4 2/3] bpf: btf: add btf print functionality | From | Daniel Borkmann <> | Date | Wed, 11 Jul 2018 22:08:35 +0200 |
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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
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