Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags and check them for following APIs: * 'map_lookup_elem()' * 'map_update_elem()' * 'generic_map_lookup_batch()' * 'generic_map_update_batch()' And, get the correct value size for these APIs. Signed-off-by: Leon Hwang --- include/linux/bpf.h | 22 ++++++++++++++++++ include/uapi/linux/bpf.h | 2 ++ kernel/bpf/syscall.c | 42 ++++++++++++++++++++++------------ tools/include/uapi/linux/bpf.h | 2 ++ 4 files changed, 54 insertions(+), 14 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 8f6e87f0f3a89..60c235836987d 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3709,4 +3709,26 @@ int bpf_prog_get_file_line(struct bpf_prog *prog, unsigned long ip, const char * const char **linep, int *nump); struct bpf_prog *bpf_prog_find_from_stack(void); +static inline int bpf_map_check_cpu_flags(u64 flags, bool check_all_cpus_flag) +{ + const u64 cpu_flags = BPF_F_CPU | BPF_F_ALL_CPUS; + u32 cpu; + + if (check_all_cpus_flag) { + if (unlikely((u32)flags > BPF_F_ALL_CPUS)) + return -EINVAL; + if (unlikely((flags & cpu_flags) == cpu_flags)) + return -EINVAL; + } else { + if (unlikely((u32)flags & ~BPF_F_CPU)) + return -EINVAL; + } + + cpu = flags >> 32; + if (unlikely((flags & BPF_F_CPU) && cpu >= num_possible_cpus())) + return -ERANGE; + + return 0; +} + #endif /* _LINUX_BPF_H */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 233de8677382e..be1fdc5042744 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1372,6 +1372,8 @@ enum { BPF_NOEXIST = 1, /* create new element if it didn't exist */ BPF_EXIST = 2, /* update existing element */ BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */ + BPF_F_CPU = 8, /* cpu flag for percpu maps, upper 32-bit of flags is a cpu number */ + BPF_F_ALL_CPUS = 16, /* update value across all CPUs for percpu maps */ }; /* flags for BPF_MAP_CREATE command */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index f5448e00a2e8f..db841b38f0c22 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -131,23 +131,36 @@ bool bpf_map_write_active(const struct bpf_map *map) return atomic64_read(&map->writecnt) != 0; } +static bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type) +{ + return false; +} + static int bpf_map_check_op_flags(struct bpf_map *map, u64 flags, u64 allowed_flags) { - if (flags & ~allowed_flags) + if ((u32)flags & ~allowed_flags) return -EINVAL; if ((flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK)) return -EINVAL; + if (!(flags & BPF_F_CPU) && flags >> 32) + return -EINVAL; + + if ((flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) && !bpf_map_supports_cpu_flags(map->map_type)) + return -EINVAL; + return 0; } -static u32 bpf_map_value_size(const struct bpf_map *map) +static u32 bpf_map_value_size(const struct bpf_map *map, u64 flags) { - if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || - map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) + if (flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) + return round_up(map->value_size, 8); + else if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || + map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) return round_up(map->value_size, 8) * num_possible_cpus(); else if (IS_FD_MAP(map)) return sizeof(u32); @@ -1687,7 +1700,7 @@ static int map_lookup_elem(union bpf_attr *attr) if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) return -EPERM; - err = bpf_map_check_op_flags(map, attr->flags, BPF_F_LOCK); + err = bpf_map_check_op_flags(map, attr->flags, BPF_F_LOCK | BPF_F_CPU); if (err) return err; @@ -1695,7 +1708,7 @@ static int map_lookup_elem(union bpf_attr *attr) if (IS_ERR(key)) return PTR_ERR(key); - value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->flags); err = -ENOMEM; value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); @@ -1762,7 +1775,7 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr) goto err_put; } - value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->flags); value = kvmemdup_bpfptr(uvalue, value_size); if (IS_ERR(value)) { err = PTR_ERR(value); @@ -1958,11 +1971,12 @@ int generic_map_update_batch(struct bpf_map *map, struct file *map_file, void *key, *value; int err = 0; - err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK); + err = bpf_map_check_op_flags(map, attr->batch.elem_flags, + BPF_F_LOCK | BPF_F_CPU | BPF_F_ALL_CPUS); if (err) return err; - value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->batch.elem_flags); max_count = attr->batch.count; if (!max_count) @@ -2017,11 +2031,11 @@ int generic_map_lookup_batch(struct bpf_map *map, u32 value_size, cp, max_count; int err; - err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK); + err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK | BPF_F_CPU); if (err) return err; - value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->batch.elem_flags); max_count = attr->batch.count; if (!max_count) @@ -2143,7 +2157,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) goto err_put; } - value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, 0); err = -ENOMEM; value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 233de8677382e..be1fdc5042744 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1372,6 +1372,8 @@ enum { BPF_NOEXIST = 1, /* create new element if it didn't exist */ BPF_EXIST = 2, /* update existing element */ BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */ + BPF_F_CPU = 8, /* cpu flag for percpu maps, upper 32-bit of flags is a cpu number */ + BPF_F_ALL_CPUS = 16, /* update value across all CPUs for percpu maps */ }; /* flags for BPF_MAP_CREATE command */ -- 2.50.1