forked from Minki/linux
f3515b5d0b
To overcome bugs as described and fixed in 89087c456f ("bpf: Fix
values type used in test_maps"), provide a generic BPF_DECLARE_PERCPU()
and bpf_percpu() accessor macro for all percpu map values used in
tests.
Declaring variables works as follows (also works for structs):
BPF_DECLARE_PERCPU(uint32_t, my_value);
They can then be accessed normally as uint32_t type through:
bpf_percpu(my_value, <cpu_nr>)
For example:
bpf_percpu(my_value, 0)++;
Implicitly, we make sure that the passed type is allocated and aligned
by gcc at least on a 8-byte boundary, so that it works together with
the map lookup/update syscall for percpu maps. We use it as a usage
example in test_maps, so that others are free to adapt this into their
code when necessary.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
#ifndef __BPF_UTIL__
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#define __BPF_UTIL__
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <asm/byteorder.h>
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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# define __bpf_ntohs(x) __builtin_bswap16(x)
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# define __bpf_htons(x) __builtin_bswap16(x)
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#elif __BYTE_ORDER == __BIG_ENDIAN
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# define __bpf_ntohs(x) (x)
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# define __bpf_htons(x) (x)
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#else
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# error "Fix your __BYTE_ORDER?!"
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#endif
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#define bpf_htons(x) \
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(__builtin_constant_p(x) ? \
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__constant_htons(x) : __bpf_htons(x))
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#define bpf_ntohs(x) \
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(__builtin_constant_p(x) ? \
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__constant_ntohs(x) : __bpf_ntohs(x))
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static inline unsigned int bpf_num_possible_cpus(void)
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{
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static const char *fcpu = "/sys/devices/system/cpu/possible";
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unsigned int start, end, possible_cpus = 0;
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char buff[128];
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FILE *fp;
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fp = fopen(fcpu, "r");
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if (!fp) {
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printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
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exit(1);
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}
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while (fgets(buff, sizeof(buff), fp)) {
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if (sscanf(buff, "%u-%u", &start, &end) == 2) {
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possible_cpus = start == 0 ? end + 1 : 0;
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break;
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}
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}
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fclose(fp);
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if (!possible_cpus) {
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printf("Failed to retrieve # possible CPUs!\n");
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exit(1);
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}
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return possible_cpus;
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}
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#define __bpf_percpu_val_align __attribute__((__aligned__(8)))
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#define BPF_DECLARE_PERCPU(type, name) \
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struct { type v; /* padding */ } __bpf_percpu_val_align \
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name[bpf_num_possible_cpus()]
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#define bpf_percpu(name, cpu) name[(cpu)].v
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#endif /* __BPF_UTIL__ */
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